Implementing RecyclerView with parseObject but getting a blank screen

Implementing RecyclerView with parseObject but getting a blank screen - java

I am trying to implement RecyclerView using ParseObject but on my screen nothing is showing up!
Following is the code for the activity where recycler view is to implemented.
AdminShowStudentId.java
package com.example.Aphexams;
import android.content.Intent;
import android.os.Bundle;
import android.app.Activity;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.View;
import android.widget.Adapter;
import android.widget.Spinner;
import android.widget.SpinnerAdapter;
import android.widget.Toast;
import com.parse.FindCallback;
import com.parse.GetCallback;
import com.parse.ParseException;
import com.parse.ParseObject;
import com.parse.ParseQuery;
import com.parse.ParseQueryAdapter;
import java.util.ArrayList;
import java.util.List;
//import app.android.project.com.olexam.R;
public class AdminShowStudentId extends Activity {
private RecyclerView recycleerviewDetails;
private RecyclerView.LayoutManager layoutManager;
private StudentIdAdapter studentidAdapter;
private ArrayList<StudentId> studentidarraylist;
private boolean notComplete = true;
private String studId;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_admin_show_student_id);
final StudentId studentId=new StudentId();
studentidarraylist=new ArrayList<StudentId>();
if(notComplete) {
ParseQuery<ParseObject> query = ParseQuery.getQuery("studAuth");
query.findInBackground(new FindCallback<ParseObject>() {
#Override
public void done(List<ParseObject> objects, ParseException e) {
if (e == null) {
for (ParseObject object : objects) {
String studentid = (String) object.get("StudUserName");
studentId.setStudentId(studentid);
studentidarraylist.add(studentId);
}
//is it fetching or not
} else {
Toast.makeText(getApplicationContext(), e.getMessage(), Toast.LENGTH_SHORT).show();
}
}
});
notComplete=false;
}
recycleerviewDetails=(RecyclerView)findViewById(R.id.studentidrecyclerview);
if (recycleerviewDetails != null)
{
recycleerviewDetails.setHasFixedSize(true);
}
/*fetching data from the database*/
studentidAdapter=new StudentIdAdapter(studentidarraylist);
recycleerviewDetails.setAdapter(studentidAdapter);
studentidAdapter.notifyDataSetChanged();
layoutManager=new GridLayoutManager(this,1);
recycleerviewDetails.setLayoutManager(layoutManager);
recycleerviewDetails.addOnItemTouchListener(new RecyclerViewListener(AdminShowStudentId.this,new RecyclerViewListener.OnItemClickListener() {
#Override
public void onItemClick(View view, int position) {
studId=studentidarraylist.get(position).getStudentId();
Intent i=new Intent(AdminShowStudentId.this,ViewStudent.class);
i.putExtra("studId",studId);
}
}));
}
}
following is the code for StudentIdAdapter.java
package com.example.Aphexams;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import java.util.ArrayList;
import java.util.List;
/**
* Created by HP on 24-05-2018.
*/
public class StudentIdAdapter extends RecyclerView.Adapter<StudentIdAdapter.StudentIdViewHolder>
{
private List<StudentId> studentIdList;
public StudentIdAdapter(ArrayList<StudentId> studentidarraylist) {
this.studentIdList=studentidarraylist;
}
#Override
public StudentIdViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view= LayoutInflater.from(parent.getContext()).inflate(R.layout.studentid_row,parent,false);
StudentIdViewHolder studentIdViewHolder=new StudentIdViewHolder(view);
return studentIdViewHolder;
}
#Override
public void onBindViewHolder(StudentIdViewHolder holder, int position) {
StudentId studentid= studentIdList.get(position);
holder.tvStudentId.setText(studentid.getStudentId());
// holder.tvanswerdate.setText(answer.getAnswerdate());
}
#Override
public int getItemCount() {
return 0;
}
public class StudentIdViewHolder extends RecyclerView.ViewHolder
{
private TextView tvStudentId;
public StudentIdViewHolder(View itemView)
{
super(itemView);
tvStudentId=(TextView)itemView.findViewById(R.id.studentidtv);
}
}
}
following is the code for RecyclerViewListener.java
package com.example.Aphexams;
import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.View;
import android.widget.AdapterView;
/**
* Created by HP on 24-05-2018.
*/
public class RecyclerViewListener implements RecyclerView.OnItemTouchListener {
private OnItemClickListener mListener;
GestureDetector mGestureDetector;
public interface OnItemClickListener
{
public void onItemClick(View view, int position);
}
public RecyclerViewListener(Context context, OnItemClickListener listener)
{
mListener = listener;
mGestureDetector = new GestureDetector(context, new GestureDetector.SimpleOnGestureListener()
{
#Override public boolean onSingleTapUp(MotionEvent e)
{
return true;
}
});
}
#Override
public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {
View childView = rv.findChildViewUnder(e.getX(),e.getY());
if(childView != null && mListener != null && mGestureDetector.onTouchEvent(e))
{
mListener.onItemClick(childView, rv.getChildAdapterPosition(childView));
return true;
}
return false;
}
#Override
public void onTouchEvent(RecyclerView rv, MotionEvent e) {
}
#Override
public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {
}
}
Following is the code for StudentId.java
package com.example.Aphexams;
/**
* Created by HP on 24-05-2018.
*/
public class StudentId {
private String StudentId;
public String getStudentId() {
return StudentId;
}
public void setStudentId(String studentId) {
StudentId = studentId;
}
}
following is my code for layout of activity_admin_show_student_id.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.NestedScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.Aphexams.AdminShowStudentId">
<android.support.v7.widget.RecyclerView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/studentidrecyclerview">
</android.support.v7.widget.RecyclerView>
</android.support.v4.widget.NestedScrollView>
following is the code for studentid
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="match_parent"
android:layout_height="20dp"
android:id="#+id/studentidtv"
android:textSize="16dp"
android:text="now you see me!"/>
</LinearLayout>
I have tried to take some help from How to use ParseObjects with a RecyclerView?.

Taking a look at you code, I guess the error is that you set you adapter with a empty list at first, then you add items to your list in your FindCallback but you never tell the list to re-render the items.
Have you checked when you set you adapter if the list is actually populated? Because since your query is running in background, there is a chance the below lines will be execute before your query finishes.
studentidAdapter=new StudentIdAdapter(studentidarraylist);
recycleerviewDetails.setAdapter(studentidAdapter);
To achieve what you are trying to do, I guess you should call
studentidAdapter=new StudentIdAdapter(studentidarraylist);
recycleerviewDetails.setAdapter(studentidAdapter);
studentidAdapter.notifyDataSetChanged();
inside your FindCallback, when you are sure your list is populated.

So, I made the following changes in my code.
AdminShowStudentId.java
As suggested by Thiago Loddi
public class AdminShowStudentId extends Activity {
private RecyclerView recycleerviewDetails;
private RecyclerView.LayoutManager layoutManager;
private StudentIdAdapter studentidAdapter;
private ArrayList<StudentId> studentidarraylist;
private boolean notComplete = true;
private String studId;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_admin_show_student_id);
recycleerviewDetails=(RecyclerView)findViewById(R.id.studentidrecyclerview);
if (recycleerviewDetails != null)
{
recycleerviewDetails.setHasFixedSize(true);
}
layoutManager=new GridLayoutManager(this,1);
recycleerviewDetails.setLayoutManager(layoutManager);
studentidarraylist=new ArrayList<StudentId>();
if(notComplete) {
ParseQuery<ParseObject> query = ParseQuery.getQuery("studAuth");
query.findInBackground(new FindCallback<ParseObject>() {
#Override
public void done(List<ParseObject> objects, ParseException e) {
if (e == null) {
for(int i=0;i<objects.size();i++)
{
String studentidstring = (String) objects.get(i).get("StudUserName");
StudentId studentId=new StudentId();
studentId.setStudentId(studentidstring);
studentidarraylist.add(studentId);
}
//Now the arraylist is populated!
for(int i=0;i<studentidarraylist.size();i++)
{
Toast.makeText(AdminShowStudentId.this,studentidarraylist.get(i).getStudentId() + " "+i, Toast.LENGTH_SHORT).show();
}
studentidAdapter=new StudentIdAdapter(studentidarraylist);
recycleerviewDetails.setAdapter(studentidAdapter);
studentidAdapter.notifyDataSetChanged();
recycleerviewDetails.addOnItemTouchListener(new RecyclerViewListener(AdminShowStudentId.this,new RecyclerViewListener.OnItemClickListener() {
#Override
public void onItemClick(View view, int position) {
studId=studentidarraylist.get(position).getStudentId();
Intent i=new Intent(AdminShowStudentId.this,ViewStudent.class);
i.putExtra("studId",studId);
startActivity(i);
}
}));
} else {
Toast.makeText(getApplicationContext(), e.getMessage(), Toast.LENGTH_SHORT).show();
}
}
});
notComplete=false;
}
}
}
And It worked!!!

Related

Getting wrong position on RecyclerView

I am trying to get the position of the item in a recycler view in order to pass it down to other activities, but after actually managing to get the item id, I found out that I'm getting a -1, therefore not getting a correct id there. What could be causing this?
The activity:
package com.gmproxy.pastilarma;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;
import androidx.lifecycle.ViewModelProvider;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.widget.SearchView;
import android.widget.Toast;
import androidx.recyclerview.*;
import com.gmproxy.Adapters.PathologyListAdapter;
import com.gmproxy.Adapters.PathologyViewHolder;
import com.gmproxy.DAO.PathologyDAO;
import com.gmproxy.Entities.Pathology;
import com.gmproxy.Util.PathologyViewModel;
public class PathologiesSearchScreen extends AppCompatActivity {
private PathologyViewModel viewModel;
SearchView searchView;
RecyclerView recyclerView;
private PathologyDAO pathDao;
private Pathology pathology;
private PathologyViewHolder holder;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_pathology_search_list);
searchView = findViewById(R.id.SearchView);
recyclerView = findViewById(R.id.recyclerview);
final PathologyListAdapter adapter = new PathologyListAdapter(new PathologyListAdapter.UserDiff());
recyclerView.setAdapter(adapter);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
viewModel = new ViewModelProvider(this).get(PathologyViewModel.class);
viewModel.pathologies.observe(this, adapter::submitList);
searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
#Override
public boolean onQueryTextSubmit(String query) {
viewModel.setFilter(searchView.getQuery().toString());
return false;
}
#Override
public boolean onQueryTextChange(String newText) {
long start;
start = System.currentTimeMillis();
if ((newText.length() > 3) && (System.currentTimeMillis() - start > 500)) {
viewModel.setFilter(searchView.getQuery().toString());
}
return false;
}
});
recyclerView.addOnItemTouchListener(new RecyclerView.OnItemTouchListener() {
#Override
public boolean onInterceptTouchEvent(#NonNull #org.jetbrains.annotations.NotNull RecyclerView rv, #NonNull #org.jetbrains.annotations.NotNull MotionEvent e) {
pathology = getSelectedPathology(findViewById(R.id.recyclerview));
Log.println(Log.INFO, "PathologyTest", pathology.toString());
final CharSequence[] options = {"Si", "No"};
AlertDialog.Builder builder = new AlertDialog.Builder(PathologiesSearchScreen.this);
builder.setTitle("¿Añadir la patología " + pathology.getPathologyName() + "?");
builder.setItems(options, new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int item) {
if (options[item].equals("Si")) {
Toast.makeText(PathologiesSearchScreen.this, "Has añadido la patología " + pathology.getPathologyName() + ".", Toast.LENGTH_SHORT).show();
Intent mainAct = new Intent(PathologiesSearchScreen.this, UserAddScreen.class);
mainAct.putExtra("path", pathology);
} else if (options[item].equals("No")) {
dialog.dismiss();
}
}
});
builder.show();
return true;
}
#Override
public void onTouchEvent(#NonNull #org.jetbrains.annotations.NotNull RecyclerView rv, #NonNull #org.jetbrains.annotations.NotNull MotionEvent e) {
}
#Override
public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {
}
});
}
public Pathology getSelectedPathology(View v){
holder = new PathologyViewHolder(v);
long idlongo = recyclerView.getAdapter().getItemId(holder.getAdapterPosition());
Log.println(Log.INFO, "PathologyTest", String.valueOf(idlongo));
int id = (int) idlongo;
Pathology path = pathDao.findObjectbyId(id);
return path;
}
}
The view holder:
package com.gmproxy.Adapters;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Filter;
import android.widget.Filterable;
import android.widget.TextView;
import android.widget.Toast;
import androidx.recyclerview.widget.RecyclerView;
import com.gmproxy.DAO.PathologyDAO;
import com.gmproxy.Entities.Pathology;
import com.gmproxy.pastilarma.PathologiesSearchScreen;
import com.gmproxy.pastilarma.R;
import java.nio.file.Path;
public class PathologyViewHolder extends RecyclerView.ViewHolder {
public final TextView objItemView;
public PathologyViewHolder(View itemView) {
super(itemView);
objItemView = itemView.findViewById(R.id.textView);
}
public void bind(String text) {
objItemView.setText(text);
}
static PathologyViewHolder create(ViewGroup parent) {
View view = LayoutInflater.from(parent.getContext())
.inflate(R.layout.pathologies_item, parent, false);
return new PathologyViewHolder(view);
}
}
The list adapter:
package com.gmproxy.Adapters;
import android.content.DialogInterface;
import android.content.Intent;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AlertDialog;
import androidx.recyclerview.widget.DiffUtil;
import androidx.recyclerview.widget.ListAdapter;
import com.gmproxy.Entities.Pathology;
import com.gmproxy.pastilarma.PathologiesSearchScreen;
import com.gmproxy.pastilarma.UserAddScreen;
public class PathologyListAdapter extends ListAdapter<Pathology, PathologyViewHolder> {
public PathologyListAdapter(#NonNull DiffUtil.ItemCallback<Pathology> diffCallback) {
super(diffCallback);
}
#Override
public PathologyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
return PathologyViewHolder.create(parent);
}
#Override
public void onBindViewHolder(PathologyViewHolder holder, int position) {
Pathology current = getItem(position);
holder.bind(current.getPathologyName());
}
public static class UserDiff extends DiffUtil.ItemCallback<Pathology> {
#Override
public boolean areItemsTheSame(#NonNull Pathology oldItem, #NonNull Pathology newItem) {
return oldItem == newItem;
}
#Override
public boolean areContentsTheSame(#NonNull Pathology oldItem, #NonNull Pathology newItem) {
return oldItem.getPathologyName().equals(newItem.getPathologyName());
}
}
}
The entity DAO:
package com.gmproxy.DAO;
import androidx.lifecycle.LiveData;
import androidx.room.*;
import com.gmproxy.Entities.Pathology;
import com.gmproxy.Entities.User;
import java.util.List;
#Dao
public interface PathologyDAO {
#Query("SELECT * FROM condiciones")
LiveData<List<Pathology>> getAllObjects();
//This will come in handy for getting all those pathologies, will need to get them on a for loop since I'm not completely sure
//that the query will handle int[]
#Query("SELECT id_condiciones FROM condiciones WHERE id_condiciones LIKE :id_condiciones")
int getPathologiesForUser(int id_condiciones);
#Query("SELECT nombreCondicion FROM condiciones WHERE nombreCondicion LIKE :pathologyName")
String getPathologiesForName(String pathologyName);
#Query("SELECT * FROM condiciones WHERE nombreCondicion LIKE :pathologyName")
Pathology getPathologiesCompleteForName(String pathologyName);
#Query("SELECT * FROM condiciones WHERE id_condiciones = :id")
Pathology findObjectbyId(int id);
#Query("SELECT * FROM condiciones WHERE nombreCondicion LIKE '%' || :filter || '%'")
LiveData<List<Pathology>> filterText(String filter);
#Insert(onConflict = OnConflictStrategy.REPLACE)
void insertAllObjects(List<Pathology> listObjects);
#Insert(onConflict = OnConflictStrategy.REPLACE)
void insertObject(Pathology object);
#Update
void updateObject(Pathology object);
#Delete
void delete(Pathology obj);
}
The entity repository:
package com.gmproxy.DAO;
import android.app.Application;
import android.os.AsyncTask;
import androidx.lifecycle.LiveData;
import com.gmproxy.Entities.Pathology;
import com.gmproxy.Entities.User;
import java.util.List;
import java.util.concurrent.ExecutionException;
public class PathologyRepository {
private PathologyDAO concerningDao;
private LiveData<List<Pathology>> pathologyList;
public PathologyRepository(Application application) {
DatabaseHelper db = DatabaseHelper.getDatabase(application);
concerningDao = db.pathologyDao();
pathologyList = concerningDao.getAllObjects();
}
public LiveData<List<Pathology>> getAllObjects() {
return concerningDao.getAllObjects();
}
void insertAllObjects(List<Pathology> objectsList) {
DatabaseHelper.databaseWriteExecutor.execute(() ->{
concerningDao.insertAllObjects(objectsList);
});
}
public void insertObject(Pathology obj){
DatabaseHelper.databaseWriteExecutor.execute(() ->{
concerningDao.insertObject(obj);
});
}
public void deleteObject(Pathology obj) {
concerningDao.delete(obj);
}
public LiveData<List<Pathology>> filter(String input){
try{
return new FilterNoteAsyncTask(concerningDao).execute(input).get();
} catch (ExecutionException | InterruptedException e) {
e.printStackTrace();
}
return null;
}
private static class FilterNoteAsyncTask extends AsyncTask<String, Void, LiveData<List<Pathology>>> {
private PathologyDAO pathologyDAO;
private FilterNoteAsyncTask(PathologyDAO pathologyDAO) {
this.pathologyDAO = pathologyDAO;
}
#Override
protected LiveData<List<Pathology>> doInBackground(String... strings) {
return pathologyDAO.filterText(strings[0]);
}
}
}

Move your PathologyListAdapter to global, and get adapter position using adapter object instead of getting adapter from recyclerview.
public Pathology getSelectedPathology(){
long idlongo = adapter.getAdapterPosition();
Log.println(Log.INFO, "PathologyTest", String.valueOf(idlongo));
int id = (int) idlongo;
Pathology path = pathDao.findObjectbyId(id);
return path;
}

Index out of Bound on Item deletion in a Recycler View's adapter

I am trying to create a note-taking app focusing on color-changing.
In one of the activity, I am trying to implement item addition and deletion to the note
picture_of_the_activity.
Item addition obviously works as intended.
The problem is with the deletion, it is very inconsistent: when I delete all the item starting from the last one upward, everything work fine; if I delete items in another order the adapter mess up, do not always delete the correct one and crashes when removing the last item.
I looked it up and found some possible solution (here or in other websites) but couldn't find a solution, or, so I thought.
I created methods inside the adapter addItem() and removeItem() so any changes is done within the class.
Maybe I am misunderstanding a concept or missing something?
Thank you in advance!
some interfaces or protion of the code are missing because I didn't implement some features yet
Activity Code
package com.example.colornoteplus;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.util.Log;
import android.view.Menu;
import android.view.MenuInflater;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.TextView;
import android.widget.Toast;
import com.google.android.material.floatingactionbutton.FloatingActionButton;
import java.text.DateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.Objects;
public class CheckListNoteActivity extends AppCompatActivity{
// note editable views
private EditText titleView;
private TextView titleCharacterCount;
private ImageButton colorView;
private RecyclerView contentView;
private FloatingActionButton fab;
CheckListAdapter adapter;
// toolbar
private Toolbar toolbar;
// Current note
private CheckListNote note;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getNoteFromIntent();
note.getContent().add(new CheckListItem("ONE"));
note.getContent().add(new CheckListItem("TWO"));
note.getContent().add(new CheckListItem("THREE"));
note.getContent().add(new CheckListItem("FOUR"));
note.getContent().add(new CheckListItem("FIVE"));
changeViewsColor(0);
}
// Method used to add menus and configure button action
// like OnClickListeners ...
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Create a submenu for sorting purpose
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.menu_check_list_activity,menu);
return super.onCreateOptionsMenu(menu);
}
// get note from the intent
private void getNoteFromIntent(){
if (!getIntent().getStringExtra(Statics.KEY_NOTE_ACTIVITY).equals(Statics.NOTE_DEFAULT_UID)){
note = MySharedPreferences.LoadCheckListNoteFromSharedPreferences(getIntent().getStringExtra(Statics.KEY_NOTE_ACTIVITY),getApplicationContext());
} else {
note = new CheckListNote();
}
}
private void changeViewsColor(int color){
// set the global theme
setTheme(StyleManager.getTheme(color));
// set the appropriate layout
setContentView(R.layout.activity_check_list_note);
// change status bar color
getWindow().setStatusBarColor(getResources().getColor(StyleManager.getThemeColor(color)));
// set up FAB action
fab = findViewById(R.id.fab_add_item);
fab.setOnClickListener(view -> onFabClickListener());
// setting the toolbar
toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
toolbar.setBackgroundColor(getResources().getColor(StyleManager.getThemeColor(color)));
Objects.requireNonNull(getSupportActionBar()).setDisplayHomeAsUpEnabled(true);
// setting the note title
titleView = findViewById(R.id.note_title_view);
titleView.setText("");
titleView.setTextColor(getResources().getColor(StyleManager.getThemeColorDark(color)));
titleView.setHintTextColor(getResources().getColor(StyleManager.getThemeColorLight(color)));
// setting the character counter for the note title
titleCharacterCount = findViewById(R.id.note_title_characters);
String m = titleView.getText().toString().trim().length()+ getString(R.string.text_divider)+ getResources().getInteger(R.integer.title_max_length);
titleCharacterCount.setText(m);
titleCharacterCount.setTextColor(getResources().getColor(StyleManager.getThemeColor(color)));
titleView.addTextChangedListener(new TextWatcher()
{
#Override
public void onTextChanged(CharSequence s, int start, int before, int count)
{
}
#Override
public void beforeTextChanged(CharSequence s, int start, int count, int aft)
{
}
#Override
public void afterTextChanged(Editable s)
{
// this will show characters remaining
String msg = titleView.getText().toString().length()+ getString(R.string.text_divider)+ getResources().getInteger(R.integer.title_max_length);
titleCharacterCount.setText(msg);
}
});
// setting the color view
colorView = findViewById(R.id.note_color_view);
colorView.setOnClickListener(view -> buildColorPickDialog());
colorView.setBackgroundResource(StyleManager.getBackground(color));
adapter = new CheckListAdapter(getApplicationContext(),note.getContent(),color);
adapter.setOnItemClickListener(new CheckListAdapter.OnItemClickListener() {
#Override
public void onChecked(int position) {
Toast.makeText(CheckListNoteActivity.this, "Checked item: " +position, Toast.LENGTH_SHORT).show();
}
#Override
public void onUnchecked(int position) {
Toast.makeText(CheckListNoteActivity.this, "Unchecked item: " +position, Toast.LENGTH_SHORT).show();
}
#Override
public void onSetPriority(int position) {
}
#Override
public void onSetReminder(int position) {
}
#Override
public void onDelete(int position) {
adapter.removeItem(position);
Toast.makeText(CheckListNoteActivity.this, "List has "+note.getContent().size()+" elements", Toast.LENGTH_SHORT).show();
}
});
contentView = findViewById(R.id.note_content_view);
contentView.setLayoutManager(new LinearLayoutManager(getApplicationContext()));
contentView.setAdapter(adapter);
}
private void switchColor(int color){
String tempTitle = titleView.getText().toString().trim();
changeViewsColor(color);
titleView.setText(tempTitle);
}
// build the color picker dialog
private void buildColorPickDialog(){
FragmentPickColor fragment = new FragmentPickColor(new ColorAdapter(),5,note.getColor());
fragment.show(getSupportFragmentManager(),Statics.TAG_FRAGMENT_COLOR_PICK);
fragment.setOnItemClickListener(new ColorAdapter.OnItemClickListener() {
#Override
public void OnClickListener(int position) {
note.setColor(position);
switchColor(position);
fragment.dismiss();
}
#Override
public void OnLongClickListener(int position) {
}
});
}
private void onFabClickListener(){
FragmentAddCheckListItem fragment = new FragmentAddCheckListItem(note.getColor());
fragment.show(getSupportFragmentManager(),Statics.TAG_FRAGMENT_ADD_CHECK_LIST_ITEM);
fragment.setOnClickListener(new FragmentAddCheckListItem.OnClickListener() {
#Override
public void onConfirmClickListener() {
fragment.getItem().setDescription(fragment.getInputText());
adapter.addItem(fragment.getItem(),0);
fragment.dismiss();
}
#Override
public void onSetPriorityClickListener() {
}
#Override
public void onSetDueTimeClickListener() {
FragmentDatePicker datePicker = new FragmentDatePicker();
datePicker.show(getSupportFragmentManager(),Statics.TAG_FRAGMENT_DATE_PICKER);
datePicker.setOnDateSet((year, month, day) -> {
Calendar c = Calendar.getInstance();
c.set(Calendar.YEAR,year);
c.set(Calendar.MONTH,month);
c.set(Calendar.DAY_OF_MONTH,day);
fragment.getItem().setDueDate(c.getTime().getTime());
fragment.setDueTimeText(DateFormat.getDateInstance().format(new Date(fragment.getItem().getDueDate())));
});
}
});
}
}
Adapter
package com.example.colornoteplus;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.constraintlayout.widget.ConstraintLayout;
import androidx.recyclerview.widget.RecyclerView;
import java.text.DateFormat;
import java.util.ArrayList;
import java.util.Date;
public class CheckListAdapter extends RecyclerView.Adapter<CheckListAdapter.MyViewHolder> {
public CheckListAdapter(Context context,ArrayList<CheckListItem> list, int color) {
this.list = list;
this.color = color;
this.context = context;
}
final private ArrayList<CheckListItem> list;
final private int color;
final private Context context;
private OnItemClickListener listener;
#NonNull
#Override
public CheckListAdapter.MyViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
return new CheckListAdapter.MyViewHolder(LayoutInflater.
from(parent.getContext()).
inflate(R.layout.item_check_list,parent,false));
}
#Override
public void onBindViewHolder(#NonNull CheckListAdapter.MyViewHolder holder, int position) {
CheckListItem currentItem = list.get(position);
holder.background.setBackgroundResource(StyleManager.getBackgroundLight(color));
holder.checkBox.setOnCheckedChangeListener((compoundButton, b) -> {
if (b) listener.onChecked(position);
else listener.onUnchecked(position);
});
holder.title.setTextColor(context.getResources().getColor(StyleManager.getThemeColorDark(color)));
holder.title.setHintTextColor(context.getResources().getColor(StyleManager.getThemeColor(color)));
assert currentItem != null;
holder.title.setText(currentItem.getDescription().trim());
holder.dueTimeText.setTextColor(context.getResources().getColor(StyleManager.getThemeColor(color)));
holder.dueTimeText.setText(currentItem.getDoneDate() != -1 ? DateFormat.getDateInstance().format(new Date(currentItem.getDueDate())) : context.getString(R.string.set_reminder));
holder.dueTimeText.setOnClickListener(view -> listener.onSetReminder(position));
holder.priorityText.setTextColor(context.getResources().getColor(StyleManager.getThemeColor(color)));
holder.priorityText.setText(currentItem.priorityToString(context));
holder.priorityText.setOnClickListener(view -> listener.onSetPriority(position));
holder.delete.setBackgroundResource(StyleManager.getBackground(color));
holder.delete.setOnClickListener(view -> {
// listener.onDelete(position);
removeItem(position);
});
}
#Override
public int getItemCount() {
return list.size();
}
public static class MyViewHolder extends RecyclerView.ViewHolder{
CheckBox checkBox;
ConstraintLayout background;
EditText title;
ImageButton delete;
TextView priorityText,dueTimeText;
public MyViewHolder(#NonNull View itemView) {
super(itemView);
checkBox = itemView.findViewById(R.id.item_check_box);
title = itemView.findViewById(R.id.item_title);
dueTimeText = itemView.findViewById(R.id.item_due_time_text);
priorityText = itemView.findViewById(R.id.item_priority_text);
delete = itemView.findViewById(R.id.item_delete);
background = itemView.findViewById(R.id.item_background);
}
}
public void addItem(CheckListItem item,int position){
if (position < 0){
list.add(item);
notifyItemInserted(list.size()-1);
}
else {
list.add(position,item);
notifyItemInserted(position);
}
}
public void removeItem(int position){
list.remove(position);
notifyItemRemoved(position);
}
public void setOnItemClickListener(OnItemClickListener listener){
this.listener = listener;
}
public interface OnItemClickListener{
void onChecked(int position);
void onUnchecked(int position);
void onSetPriority(int position);
void onSetReminder(int position);
void onDelete(int position);
}
}

public void addItem(CheckListItem item, int position) {
if (position >= 0) {
list.add(position, item);
notifyItemInserted(position);
}
}
public void removeItem(int position) {
if (position >= 0) {
list.remove(position);
notifyItemRemoved(position);
}
}
And in onBindViewHolder use holder.getAdapterPosition() instead of position in your listeners like this:
holder.delete.setOnClickListener(view -> {
// listener.onDelete(position);
removeItem(holder.getAdapterPosition());
});

Everytime I have to change something to reflect [closed]

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In my chat App FriendsFragment is shwoing blank. If I want to reflect that then, I have run the app, open the Friends tab in my app and after Instant run in Android studio and it will reflect. If it will not, then I have to add Log statement anywhere in my FriendsFragment, and run Instant run with exctly the open tab of friendsfragmet.
Why I'm telling you to add Log statement is necessary because I found this bug that whenever I change something on my Friends Fragment and then run Instant run, then only it will show the Fragment part. And I have to do this every time, otherwise it won't show. Add Log statement and remove second time, or change tag or change message, do something that makes the changes, and must run Instant run (that Yellow symbol like booster).
NOTE: I'm still doing this thing, I observe this problem by myself and I also don't know why I have to change something every time to show this Fragment? I also built the similar fragment in this same app, but for that there is no problem!
FriendFragment
package com.jimmytrivedi.lapitchat;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.v4.app.Fragment;
import android.support.v7.app.AlertDialog;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import com.firebase.ui.database.FirebaseRecyclerAdapter;
import com.firebase.ui.database.FirebaseRecyclerOptions;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.Query;
import com.google.firebase.database.ValueEventListener;
import com.squareup.picasso.Picasso;
import de.hdodenhof.circleimageview.CircleImageView;
public class FriendsFragment extends Fragment {
private RecyclerView FriendRecyclerView;
private DatabaseReference databaseReference, UsersDatabaseReference;
private FirebaseAuth mAuth;
private String currentUID;
private View MainView;
public FriendsFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
MainView = inflater.inflate(R.layout.fragment_friend, container, false);
FriendRecyclerView = MainView.findViewById(R.id.FriendRecyclerView);
mAuth = FirebaseAuth.getInstance();
if (mAuth.getCurrentUser() != null) {
currentUID = mAuth.getCurrentUser().getUid();
databaseReference = FirebaseDatabase.getInstance().getReference().child("Friends").child(currentUID);
databaseReference.keepSynced(true);
UsersDatabaseReference = FirebaseDatabase.getInstance().getReference().child("Users");
UsersDatabaseReference.keepSynced(true);
}
FriendRecyclerView.setHasFixedSize(true);
FriendRecyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
Log.d("wihddiewd", "Is it going?");
return MainView;
}
#Override
public void onStart() {
super.onStart();
Query query = FirebaseDatabase. getInstance()
.getReference()
.child("Friends")
.limitToLast(50);
FirebaseRecyclerOptions<Friends> options = new FirebaseRecyclerOptions.Builder<Friends>()
.setQuery(query, Friends.class)
.build();
final FirebaseRecyclerAdapter<Friends, FriendsViewHolder> FriendsRecyclerViewAdapter = new
FirebaseRecyclerAdapter<Friends, FriendsViewHolder>(options) {
#Override
protected void onBindViewHolder(#NonNull final FriendsViewHolder holder, int position, #NonNull Friends model) {
holder.setDate(model.getDate());
final String listUID = getRef(position).getKey();
UsersDatabaseReference.child(listUID).addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
final String userName = dataSnapshot.child("Name").getValue().toString();
String thumbImage = dataSnapshot.child("thumbImage").getValue().toString();
String userOnline = dataSnapshot.child("Online").getValue().toString();
holder.setName(userName);
holder.setThumbImage(thumbImage, getContext());
holder.setUserOnline(userOnline);
holder.mView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
CharSequence options[] = new CharSequence[]{"Open profile", "Send message"};
AlertDialog.Builder builder = new AlertDialog.Builder(getContext());
builder.setTitle("Select Options");
builder.setItems(options, new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
if (which == 0) {
Intent intent = new Intent(getContext(), ProfileActivity.class);
intent.putExtra("userID", listUID);
startActivity(intent);
}
if (which == 1) {
Intent intent = new Intent(getContext(), ChatActivity.class);
intent.putExtra("userID", listUID);
intent.putExtra("userName", userName);
startActivity(intent);
}
}
});
builder.show();
}
});
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
}
});
}
#NonNull
#Override
public FriendsViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.users_single_layout, parent, false);
return new FriendsViewHolder(view);
}
};
FriendRecyclerView.setAdapter(FriendsRecyclerViewAdapter);
FriendsRecyclerViewAdapter.startListening();
}
public static class FriendsViewHolder extends RecyclerView.ViewHolder {
View mView;
public FriendsViewHolder(View itemView) {
super(itemView);
mView = itemView;
}
public void setDate(String date) {
TextView userStatusView = mView.findViewById(R.id.userStatus);
userStatusView.setText(date);
}
public void setName(String name) {
TextView userNameView = mView.findViewById(R.id.userName);
userNameView.setText(name);
}
public void setThumbImage(String thumbImage, Context context) {
CircleImageView circleImageView = mView.findViewById(R.id.userImage);
Picasso.get().load(thumbImage).placeholder(R.drawable.defaultimage)
.into(circleImageView);
}
public void setUserOnline(String online) {
ImageView userOnline = mView.findViewById(R.id.online);
if (online.equals("true")) {
userOnline.setVisibility(View.VISIBLE);
} else {
userOnline.setVisibility(View.INVISIBLE);
}
}
}
}
Update
I know this is weird bug. But basically when I open my app and in app firends tab (which is FriendsFragment.java), it is showing blank. So I tried to debug that is there any mistake on my code or not? But I didn't find. But while debugging time, when I go to my firends tab in my mobile app, and put any log statement in Android Studio (because when I add/remove something so Android Studio will understand that some changes made happen, and then I run Instant run(not normal run) then FriendFragment will reflect and it shows the user list.
And I have to do this every time, (means I have to add something/remove something, that consider changes for Android Studio) then only FriendsFragment will show the users list. And even if I not open my Friends tab, but open something else in app and than run (instant run) that is also not work! Only when I just go to friends tab (that time it is showing blank, but that is okay) and run Instant run, then only it will reflect.
fragment_friends.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".FriendsFragment">
<android.support.v7.widget.RecyclerView
android:id="#+id/FriendRecyclerView"
android:layout_width="match_parent"
android:layout_height="wrap_content">
</android.support.v7.widget.RecyclerView>
</RelativeLayout>
users_single_layout.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<de.hdodenhof.circleimageview.CircleImageView
android:id="#+id/userImage"
android:layout_width="64dp"
android:layout_height="64dp"
android:layout_marginBottom="15dp"
android:layout_marginLeft="15dp"
android:layout_marginTop="15dp"
android:src="#drawable/defaultimage" />
<TextView
android:id="#+id/userName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentStart="true"
android:layout_alignTop="#+id/userImage"
android:layout_marginStart="99dp"
android:text="Display Name"
android:textColor="#000000"
android:textSize="18dp" />
<TextView
android:id="#+id/userStatus"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignStart="#+id/userName"
android:layout_below="#+id/userName"
android:text="User default Status"
android:textSize="15dp" />
<ImageView
android:id="#+id/online"
android:layout_width="8dp"
android:layout_height="wrap_content"
android:layout_alignTop="#+id/userName"
android:layout_marginLeft="10dp"
android:layout_toEndOf="#+id/userName"
android:visibility="invisible"
android:src="#drawable/online" />
</RelativeLayout>
Another Fragment ChatFragment, which is similar to this and working pretty fine).
ChatFragment.java
package com.jimmytrivedi.lapitchat;
import android.content.Context;
import android.content.Intent;
import android.graphics.Typeface;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import com.firebase.ui.database.FirebaseRecyclerAdapter;
import com.firebase.ui.database.FirebaseRecyclerOptions;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.database.ChildEventListener;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.Query;
import com.google.firebase.database.ValueEventListener;
import com.squareup.picasso.Picasso;
import de.hdodenhof.circleimageview.CircleImageView;
public class ChatFragment extends Fragment {
private RecyclerView ConversationList;
private DatabaseReference ConversationRef, MessageRef, UserRef;
private FirebaseAuth mAuth;
private String currentUID;
private View MainView;
public ChatFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
MainView = inflater.inflate(R.layout.fragment_chat, container, false);
ConversationList = MainView.findViewById(R.id.ConversationList);
mAuth = FirebaseAuth.getInstance();
currentUID = mAuth.getCurrentUser().getUid();
ConversationRef = FirebaseDatabase.getInstance().getReference().child("Chat").child(currentUID);
ConversationRef.keepSynced(true);
UserRef = FirebaseDatabase.getInstance().getReference().child("Users");
UserRef.keepSynced(true);
MessageRef = FirebaseDatabase.getInstance().getReference().child("Messages").child(currentUID);
LinearLayoutManager layoutManager = new LinearLayoutManager(getContext());
layoutManager.setReverseLayout(true);
layoutManager.setStackFromEnd(true);
ConversationList.setHasFixedSize(true);
ConversationList.setLayoutManager(layoutManager);
return MainView;
}
#Override
public void onStart() {
super.onStart();
Query conversationQuery = ConversationRef.orderByChild("timestamp");
Query query = FirebaseDatabase.getInstance()
.getReference()
.child("Chat")
.limitToLast(50);
FirebaseRecyclerOptions<Conversation> options = new FirebaseRecyclerOptions.Builder<Conversation>()
.setQuery(query, Conversation.class)
.build();
FirebaseRecyclerAdapter<Conversation, ConversationViewHolder> ConversationRecyclerViewAdapter = new
FirebaseRecyclerAdapter<Conversation, ConversationViewHolder>(options) {
#Override
protected void onBindViewHolder(#NonNull final ConversationViewHolder holder, int position, #NonNull final Conversation model) {
final String listUID = getRef(position).getKey();
Query lastMessageQuery = MessageRef.child(listUID).limitToLast(1);
lastMessageQuery.addChildEventListener(new ChildEventListener() {
#Override
public void onChildAdded(#NonNull DataSnapshot dataSnapshot, #Nullable String s) {
String data = dataSnapshot.child("message").getValue().toString();
holder.setMassage(data, model.isSeen());
}
#Override
public void onChildChanged(#NonNull DataSnapshot dataSnapshot, #Nullable String s) {
}
#Override
public void onChildRemoved(#NonNull DataSnapshot dataSnapshot) {
}
#Override
public void onChildMoved(#NonNull DataSnapshot dataSnapshot, #Nullable String s) {
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
}
});
UserRef.child(listUID).addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
final String userName = dataSnapshot.child("Name").getValue().toString();
String userThumb = dataSnapshot.child("thumbImage").getValue().toString();
if (dataSnapshot.hasChild("Online")) {
String userOnline = dataSnapshot.child("Online").getValue().toString();
holder.setUserOnline(userOnline);
}
holder.setName(userName);
holder.setUserImage(userThumb, getContext());
holder.mView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(getContext(), ChatActivity.class);
intent.putExtra("userID", listUID);
intent.putExtra("userName", userName);
startActivity(intent);
}
});
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
}
});
}
#NonNull
#Override
public ConversationViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.users_single_layout, parent, false);
return new ConversationViewHolder(view);
}
};
ConversationList.setAdapter(ConversationRecyclerViewAdapter);
ConversationRecyclerViewAdapter.startListening();
}
public static class ConversationViewHolder extends RecyclerView.ViewHolder {
View mView;
public ConversationViewHolder(View itemView) {
super(itemView);
mView = itemView;
}
public void setMassage(String message, boolean isSeen) {
TextView userStatusView = mView.findViewById(R.id.userStatus);
userStatusView.setText(message);
if (!isSeen) {
userStatusView.setTypeface(userStatusView.getTypeface(), Typeface.BOLD);
} else {
userStatusView.setTypeface(userStatusView.getTypeface(), Typeface.NORMAL);
}
}
public void setUserOnline(String online) {
ImageView userOnlineView = mView.findViewById(R.id.online);
if (online.equals("true")) {
userOnlineView.setVisibility(View.VISIBLE);
} else {
userOnlineView.setVisibility(View.INVISIBLE);
}
}
public void setName(String userName) {
TextView userNameView = mView.findViewById(R.id.userName);
userNameView.setText(userName);
}
public void setUserImage(String userThumb, Context context) {
CircleImageView userImageView = mView.findViewById(R.id.userImage);
Picasso.get().load(userThumb).placeholder(R.drawable.defaultimage).into(userImageView);
}
}
}
Friends.java
package com.jimmytrivedi.lapitchat;
public class Friends {
public String date;
public Friends() {
}
public Friends(String date) {
this.date = date;
}
public String getDate() {
return date;
}
public void setDate(String date) {
this.date = date;
}
}
SectionPagerAdapter.java
package com.jimmytrivedi.lapitchat;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
RequestFragment requestFragment = new RequestFragment();
return requestFragment;
case 1:
ChatFragment chatFragment = new ChatFragment();
return chatFragment;
case 2:
FriendsFragment friendFragment = new FriendsFragment();
return friendFragment;
default:
return null;
}
}
#Override
public int getCount() {
return 3;
}
#Nullable
#Override
public CharSequence getPageTitle(int position) {
switch (position) {
case 0:
return "Requests";
case 1:
return "Chats";
case 2:
return "Friends";
default:
return null;
}
}
}
MainActivity.java
package com.jimmytrivedi.lapitchat;
import android.content.Intent;
import android.os.Bundle;
import android.support.design.widget.TabLayout;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import com.facebook.login.LoginManager;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ServerValue;
public class MainActivity extends AppCompatActivity {
private FirebaseAuth mAuth;
private FirebaseUser currentUser;
private Toolbar toolbar;
private ViewPager viewPager;
private SectionsPagerAdapter sectionsPagerAdapter;
private TabLayout tabLayout;
private DatabaseReference UserDatabaseReference;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mAuth = FirebaseAuth.getInstance();
currentUser = mAuth.getCurrentUser();
if (currentUser == null) {
sendTostart();
} else {
UserDatabaseReference = FirebaseDatabase.getInstance().getReference().child("Users").child(mAuth.getCurrentUser().getUid());
UserDatabaseReference.child("Online").setValue("true");
}
viewPager = findViewById(R.id.viewPager);
sectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
viewPager.setAdapter(sectionsPagerAdapter);
toolbar = findViewById(R.id.mainToolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setTitle("Home");
tabLayout = findViewById(R.id.tabLayout);
tabLayout.setupWithViewPager(viewPager);
}
#Override
protected void onPause() {
super.onPause();
if (currentUser != null) {
UserDatabaseReference.child("Online").setValue(ServerValue.TIMESTAMP);
}
}
private void sendTostart() {
startActivity(new Intent(MainActivity.this, StartActivity.class));
finish();
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
super.onCreateOptionsMenu(menu);
getMenuInflater().inflate(R.menu.main_menu, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
super.onOptionsItemSelected(item);
if (item.getItemId() == R.id.logout) {
FirebaseAuth.getInstance().signOut();
LoginManager.getInstance().logOut();
sendTostart();
}
if (item.getItemId() == R.id.settings) {
startActivity(new Intent(MainActivity.this, SettingsActivity.class));
}
if (item.getItemId() == R.id.allUsers) {
startActivity(new Intent(MainActivity.this, UsersActivity.class));
}
return true;
}
}

Use
`viewPager.setOffscreenPageLimit(3);`
after
viewPager.setAdapter(sectionsPagerAdapter);
inside MainActivity.

Use notifyDataSetChanged() after setting adapter to recyclerview.
FriendRecyclerView.setAdapter(FriendsRecyclerViewAdapter);
FriendsRecyclerViewAdapter.notifyDataSetChanged();

Can't Update Recyclerview adapter with new list,new list showing blank

I want to get new updated list in Favourite activity,but instead i'm getting no items in favourite list.List getting values from sharedpreference but not updating to recycler view.
DiseaseAdapter
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.os.Build;
import android.support.annotation.RequiresApi;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.List;
/**
* Created by admin on 12/4/2017.
*/
public class DiseaseAdapter extends RecyclerView.Adapter<DiseaseAdapter.DiseaseAdapterViewHolder> {
List <String> data;
Context ctx;
SharedPreference sharedPreference;
DiseaseAdapter(List <String> data, Context ctx){
this.data=data;
notifyDataSetChanged();
this.ctx=ctx;
sharedPreference = new SharedPreference();
}
#Override
public DiseaseAdapterViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
LayoutInflater inflater=LayoutInflater.from(parent.getContext());
View view= inflater.inflate(R.layout.activity_listview,parent,false);
return new DiseaseAdapterViewHolder(view);
}
#Override
public void onBindViewHolder(DiseaseAdapterViewHolder holder, int position) {
final String title=data.get(position);
holder.textView1.setText(title);
if (checkFavoriteItem(title)) {
holder.imageButton.setImageResource(R.drawable.star_colour);
holder.imageButton.setTag("red");
} else {
holder.imageButton.setImageResource(R.drawable.ic_action_name);
holder.imageButton.setTag("grey");
}
}
#Override
public int getItemCount() {
return data.size();
}
class DiseaseAdapterViewHolder extends RecyclerView.ViewHolder {
TextView textView1;
ImageView imageButton;
public DiseaseAdapterViewHolder(View itemView) {
super(itemView);
textView1=(TextView) itemView.findViewById(R.id.textView);
imageButton=(ImageView)itemView.findViewById(R.id.imgbtn_favorite);
}
}
/*Checks whether a particular product exists in SharedPreferences*/
public boolean checkFavoriteItem(String checkProduct) {
boolean check = false;
List<String> favorites = sharedPreference.getFavorites(ctx);
if (favorites != null) {
for (String product : favorites) {
if (product.equals(checkProduct)) {
check = true;
break;
}
}
}
return check;
}
}
MainActivity
import android.content.Context;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ImageView;
import android.widget.Toast;
import java.util.Arrays;
import java.util.List;
public class MainActivity extends AppCompatActivity{
RecyclerView simpleListView;
static Context ctx;
String diseaseList[];
SharedPreference sharedPreference;
DiseaseAdapter da;
List<String> newDiseaseList;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ctx=this;
sharedPreference = new SharedPreference();
diseaseList= new String[]{"Abscess",
"Allergies",
"Amnesia",
"Anemia",
"Andropause",
"Angina",
"Weight Loss"};
Arrays.sort(diseaseList);
newDiseaseList = Arrays.asList(diseaseList);
simpleListView= (RecyclerView)findViewById(R.id.simpleListView);
LinearLayoutManager lm=new LinearLayoutManager(MainActivity.this);
simpleListView.setLayoutManager(lm);
/* DividerItemDecoration di=new DividerItemDecoration(MainActivity.this,lm.getOrientation());
simpleListView.addItemDecoration(di);*/
da=new DiseaseAdapter(newDiseaseList,ctx);
simpleListView.setAdapter(da);
simpleListView.setHasFixedSize(true);
simpleListView.addOnItemTouchListener(
new RecyclerItemClickListener(ctx, simpleListView ,new RecyclerItemClickListener.OnItemClickListener() {
#Override public void onItemClick(View view, int position) {
ImageView button = (ImageView) view.findViewById(R.id.imgbtn_favorite);
String tag = button.getTag().toString();
if (tag.equalsIgnoreCase("grey")) {
sharedPreference.addFavorite(ctx, newDiseaseList.get(position));
Toast.makeText(ctx,
"add to favourites",
Toast.LENGTH_SHORT).show();
button.setTag("red");
button.setImageResource(R.drawable.star_colour);
} else {
sharedPreference.removeFavorite(ctx, newDiseaseList.get(position));
button.setTag("grey");
button.setImageResource(R.drawable.ic_action_name);
Toast.makeText(ctx,
"removed from favourites",
Toast.LENGTH_SHORT).show();
}
}
#Override public void onLongItemClick(View view, int position) {
}
})
);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.menu_favorites:
Intent i=new Intent(this,Favourite.class);
this.startActivity(i);
return true;
}
return super.onOptionsItemSelected(item);
}
}
SharedPreference.java
import android.content.Context;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import com.google.gson.Gson;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
public class SharedPreference {
public static final String PREFS_NAME = "PRODUCT_APP";
public static final String FAVORITES = "Product_Favorite";
public SharedPreference() {
super();
}
// This four methods are used for maintaining favorites.
public void saveFavorites(Context context, List<String> favorites) {
SharedPreferences settings;
Editor editor;
settings = context.getSharedPreferences(PREFS_NAME,
Context.MODE_PRIVATE);
editor = settings.edit();
Gson gson = new Gson();
String jsonFavorites = gson.toJson(favorites);
editor.putString(FAVORITES, jsonFavorites);
editor.commit();
}
public void addFavorite(Context context, String product) {
List<String> favorites = getFavorites(context);
if (favorites == null)
favorites = new ArrayList<String>();
favorites.add(product);
saveFavorites(context, favorites);
}
public void removeFavorite(Context context, String product) {
List<String> favorites = getFavorites(context);
if (favorites != null) {
favorites.remove(product);
saveFavorites(context, favorites);
}
}
public ArrayList<String> getFavorites(Context context) {
SharedPreferences settings;
List<String> favorites ;
settings = context.getSharedPreferences(PREFS_NAME,
Context.MODE_PRIVATE);
if (settings.contains(FAVORITES)) {
String jsonFavorites = settings.getString(FAVORITES, null);
Gson gson = new Gson();
String [] favoriteItems = (gson.fromJson(jsonFavorites,String [].class));
favorites = Arrays.asList(favoriteItems);
favorites = new ArrayList<String>(favorites);
} else
return null;
return (ArrayList<String>) favorites;
}
}
Favourite.java
import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.Toast;
import java.util.List;
public class Favourite extends AppCompatActivity {
RecyclerView favoriteList;
SharedPreference sharedPreference;
List<String> favorites;
DiseaseAdapter diseaseAdapter;
Context ctx;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_favourite);
ctx=this;
sharedPreference = new SharedPreference();
favorites = sharedPreference.getFavorites(ctx);
favoriteList = (RecyclerView)findViewById(R.id.favListView);
if (favorites == null) {
showAlert(getResources().getString(R.string.no_favorites_items),
getResources().getString(R.string.no_favorites_msg));
} else {
if (favorites.size() == 0) {
showAlert(
getResources().getString(R.string.no_favorites_items),
getResources().getString(R.string.no_favorites_msg));
}
if (favorites != null) {
diseaseAdapter = new DiseaseAdapter(favorites,ctx);
diseaseAdapter.notifyDataSetChanged();
favoriteList.setAdapter(diseaseAdapter);
favoriteList.invalidate();
favoriteList.addOnItemTouchListener(
new RecyclerItemClickListener(ctx, favoriteList ,new RecyclerItemClickListener.OnItemClickListener() {
#Override public void onItemClick(View view, int position) {
ImageView button = (ImageView) view
.findViewById(R.id.imgbtn_favorite);
String tag = button.getTag().toString();
if (tag.equalsIgnoreCase("grey")) {
sharedPreference.addFavorite(ctx,
favorites.get(position));
Toast.makeText(
ctx,
ctx.getResources().getString(
R.string.add_favr),
Toast.LENGTH_SHORT).show();
button.setTag("red");
button.setImageResource(R.drawable.star_colour);
} else {
sharedPreference.removeFavorite(ctx,
favorites.get(position));
button.setTag("grey");
button.setImageResource(R.drawable.ic_action_name);
/* diseaseAdapter.remove(favorites
.get(position));*/
diseaseAdapter.notifyItemRemoved(position);
Toast.makeText(
ctx,
ctx.getResources().getString(
R.string.remove_favr),
Toast.LENGTH_SHORT).show();
}
}
#Override public void onLongItemClick(View view, int position) {
}
})
);
}
}
}
public void showAlert(String title, String message) {
if (ctx != null) {
AlertDialog alertDialog = new AlertDialog.Builder(ctx)
.create();
alertDialog.setTitle(title);
alertDialog.setMessage(message);
alertDialog.setCancelable(false);
// setting OK Button
alertDialog.setButton(AlertDialog.BUTTON_POSITIVE, "OK",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
// activity.finish();
getFragmentManager().popBackStackImmediate();
}
});
alertDialog.show();
}
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.admin.fav.MainActivity">
<android.support.v7.widget.RecyclerView
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/simpleListView"
>
</android.support.v7.widget.RecyclerView>
</RelativeLayout>
activity_listview.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<TextView
android:id="#+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:textSize="20dp"
android:paddingTop="10dp"
android:paddingBottom="10dp"
android:paddingLeft="10dp"
android:textColor="#434b3e"
android:text=""/>
<ImageView
android:id="#+id/imgbtn_favorite"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_marginRight="3dp"
android:background="#null"
/>
</RelativeLayout>
activity_favourite.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.admin.fav.Favourite">
<android.support.v7.widget.RecyclerView
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/favListView"
>
</android.support.v7.widget.RecyclerView>
</RelativeLayout>

You are missing setLayoutManager() in Favourite.java.

Try calling NotifyDataSetChanged() instead of NotifyItemRemoved() or NotifyItemAdded(). These methods did not work for me either. You just won't get the animations of items being added and removed but you can add your own animations to do the trick!
You should use Room Database to store lists and handle them as it is much easier and makes a lot of sense. SharedPreferences is recommended for storing values such as integers and booleans, not whole lists.

Getting error index out of bound exception in my recyclerview

I'm trying to get favourite items in favourite list from main list.When i click on favourite icon in mainlist, favouritelist get updating but when i remove any favourite from favouritelist and trying to add more favourites from mainlist i get error index out of bound exception
MainActivity
import android.content.Context;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ImageView;
import android.widget.Toast;
import java.util.Arrays;
import java.util.List;
public class MainActivity extends AppCompatActivity implements RecyclerViewClickListener{
RecyclerView simpleListView;
static Context ctx;
String diseaseList[];
SharedPreference sharedPreference;
DiseaseAdapter da;
List<String> newDiseaseList;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ctx=this;
sharedPreference = new SharedPreference();
diseaseList= new String[]{"Abscess",
"Allergies",
"Amnesia",
"Anemia",
"Andropause",
"Angina",
"Weight Loss"};
Arrays.sort(diseaseList);
newDiseaseList = Arrays.asList(diseaseList);
simpleListView= (RecyclerView)findViewById(R.id.simpleListView);
LinearLayoutManager lm=new LinearLayoutManager(MainActivity.this);
simpleListView.setLayoutManager(lm);
/* DividerItemDecoration di=new DividerItemDecoration(MainActivity.this,lm.getOrientation());
simpleListView.addItemDecoration(di);*/
da=new DiseaseAdapter(newDiseaseList,ctx,this);
simpleListView.setAdapter(da);
simpleListView.setHasFixedSize(true);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.menu_favorites:
Intent i=new Intent(this,Favourite.class);
this.startActivity(i);
return true;
}
return super.onOptionsItemSelected(item);
}
#Override
protected void onResume() {
super.onResume();
da.notifyDataSetChanged();
}
#Override
public void recyclerViewListClicked(View view, int position) {
ImageView button = (ImageView) view.findViewById(R.id.imgbtn_favorite);
String tag = button.getTag().toString();
if (tag.equalsIgnoreCase("grey")) {
sharedPreference.addFavorite(ctx, newDiseaseList.get(position));
Toast.makeText(ctx,
"add to favourites",
Toast.LENGTH_SHORT).show();
button.setTag("red");
button.setImageResource(R.drawable.star_colour);
} else {
sharedPreference.removeFavorite(ctx, newDiseaseList.get(position));
button.setTag("grey");
button.setImageResource(R.drawable.ic_action_name);
Toast.makeText(ctx,
"removed from favourites",
Toast.LENGTH_SHORT).show();
}
}
}
Favourite.java
import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.Toast;
import java.util.Collections;
import java.util.List;
public class Favourite extends AppCompatActivity implements RecyclerViewClickListener {
RecyclerView favoriteList;
SharedPreference sharedPreference;
List<String> favorites;
DiseaseAdapter diseaseAdapter;
static Context ctx;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_favourite);
ctx=this;
sharedPreference = new SharedPreference();
favorites = sharedPreference.getFavorites(ctx);
Collections.sort(favorites);
favoriteList = (RecyclerView)findViewById(R.id.favListView);
LinearLayoutManager lm=new LinearLayoutManager(ctx);
favoriteList.setLayoutManager(lm);
favoriteList.setHasFixedSize(true);
if (favorites == null) {
showAlert(getResources().getString(R.string.no_favorites_items),
getResources().getString(R.string.no_favorites_msg));
} else {
if (favorites.size() == 0) {
showAlert(
getResources().getString(R.string.no_favorites_items),
getResources().getString(R.string.no_favorites_msg));
}
if (favorites != null) {
diseaseAdapter = new DiseaseAdapter(favorites,ctx,this);
favoriteList.setAdapter(diseaseAdapter);
}
}
}
public void showAlert(String title, String message) {
if (ctx != null) {
AlertDialog alertDialog = new AlertDialog.Builder(ctx)
.create();
alertDialog.setTitle(title);
alertDialog.setMessage(message);
alertDialog.setCancelable(false);
// setting OK Button
alertDialog.setButton(AlertDialog.BUTTON_POSITIVE, "OK",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
// activity.finish();
getFragmentManager().popBackStackImmediate();
}
});
alertDialog.show();
}
}
#Override
public void recyclerViewListClicked(View view, int position) {
ImageView button = (ImageView) view
.findViewById(R.id.imgbtn_favorite);
String tag = button.getTag().toString();
if (tag.equalsIgnoreCase("grey")) {
sharedPreference.addFavorite(ctx,
favorites.get(position));
Toast.makeText(
ctx,
ctx.getResources().getString(
R.string.add_favr),
Toast.LENGTH_SHORT).show();
button.setTag("red");
button.setImageResource(R.drawable.star_colour);
} else {
sharedPreference.removeFavorite(ctx,
favorites.get(position));
button.setTag("grey");
button.setImageResource(R.drawable.ic_action_name);
/* diseaseAdapter.remove(favorites
.get(position));*/
diseaseAdapter.remove(position);
Toast.makeText(
ctx,
ctx.getResources().getString(
R.string.remove_favr),
Toast.LENGTH_SHORT).show();
}
}
}
Adapter
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.os.Build;
import android.support.annotation.RequiresApi;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.List;
/**
* Created by admin on 12/4/2017.
*/
public class DiseaseAdapter extends RecyclerView.Adapter<DiseaseAdapter.DiseaseAdapterViewHolder> {
List <String> data;
Context ctx;
private static RecyclerViewClickListener itemListener;
SharedPreference sharedPreference;
DiseaseAdapter(List <String> data, Context ctx, RecyclerViewClickListener itemListener){
this.data=data;
this.ctx=ctx;
sharedPreference = new SharedPreference();
this.itemListener = itemListener;
notifyDataSetChanged();
}
#Override
public DiseaseAdapterViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
LayoutInflater inflater=LayoutInflater.from(parent.getContext());
View view= inflater.inflate(R.layout.activity_listview,parent,false);
return new DiseaseAdapterViewHolder(view);
}
#Override
public void onBindViewHolder(DiseaseAdapterViewHolder holder, int position) {
final String title=data.get(position);
holder.textView1.setText(title);
if (checkFavoriteItem(title)) {
holder.imageButton.setImageResource(R.drawable.star_colour);
holder.imageButton.setTag("red");
} else {
holder.imageButton.setImageResource(R.drawable.ic_action_name);
holder.imageButton.setTag("grey");
}
}
#Override
public int getItemCount() {
return data.size();
}
class DiseaseAdapterViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
TextView textView1;
ImageView imageButton;
public DiseaseAdapterViewHolder(View itemView) {
super(itemView);
textView1=(TextView) itemView.findViewById(R.id.textView);
imageButton=(ImageView)itemView.findViewById(R.id.imgbtn_favorite);
imageButton.setOnClickListener(this);
}
#Override
public void onClick(View v) {
notifyDataSetChanged();
itemListener.recyclerViewListClicked(v, this.getLayoutPosition());
}
}
/*Checks whether a particular product exists in SharedPreferences*/
public boolean checkFavoriteItem(String checkProduct) {
boolean check = false;
List<String> favorites = sharedPreference.getFavorites(ctx);
if (favorites != null) {
for (String product : favorites) {
if (product.equals(checkProduct)) {
check = true;
break;
}
}
}
return check;
}
public void add(String product) {
data.add(product);
notifyDataSetChanged();
}
public void remove(int position) {
data.remove(position);
notifyItemRemoved(position);
notifyItemRangeChanged(position, data.size());
notifyDataSetChanged();
}
}
SharedPreference
import android.content.Context;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import com.google.gson.Gson;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
public class SharedPreference {
public static final String PREFS_NAME = "PRODUCT_APP";
public static final String FAVORITES = "Product_Favorite";
public SharedPreference() {
super();
}
// This four methods are used for maintaining favorites.
public void saveFavorites(Context context, List<String> favorites) {
SharedPreferences settings;
Editor editor;
settings = context.getSharedPreferences(PREFS_NAME,
Context.MODE_PRIVATE);
editor = settings.edit();
Gson gson = new Gson();
String jsonFavorites = gson.toJson(favorites);
editor.putString(FAVORITES, jsonFavorites);
editor.commit();
}
public void addFavorite(Context context, String product) {
List<String> favorites = getFavorites(context);
if (favorites == null)
favorites = new ArrayList<String>();
favorites.add(product);
saveFavorites(context, favorites);
}
public void removeFavorite(Context context, String product) {
List<String> favorites = getFavorites(context);
if (favorites != null) {
favorites.remove(product);
saveFavorites(context, favorites);
}
}
public ArrayList<String> getFavorites(Context context) {
SharedPreferences settings;
List<String> favorites ;
settings = context.getSharedPreferences(PREFS_NAME,
Context.MODE_PRIVATE);
if (settings.contains(FAVORITES)) {
String jsonFavorites = settings.getString(FAVORITES, null);
Gson gson = new Gson();
String [] favoriteItems = (gson.fromJson(jsonFavorites,String [].class));
favorites = Arrays.asList(favoriteItems);
favorites = new ArrayList<String>(favorites);
} else
return null;
return (ArrayList<String>) favorites;
}
}
This is an error that i'm getting
FATAL EXCEPTION: main
Process: com.example.admin.fav, PID: 10974
java.lang.IndexOutOfBoundsException: Invalid index 3, size is 3
at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:255)
at java.util.ArrayList.get(ArrayList.java:308)
at com.example.admin.fav.Favourite.recyclerViewListClicked(Favourite.java:145)
at com.example.admin.fav.DiseaseAdapter$DiseaseAdapterViewHolder.onClick(DiseaseAdapter.java:90)
at android.view.View.performClick(View.java:5207)
at android.view.View$PerformClick.run(View.java:21168)
at android.os.Handler.handleCallback(Handler.java:746)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5443)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:728)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)

Problem in your listener. You are using same adapter class for both MainActivity recylerview & Favourite activity recylerview. After you go back from favourite activity to Mainactivity still your listener read from Favourite activity. Thats the issue.
Solution
Create Static field to hold listener value here am created in SharedPreference Class:
public class SharedPreference {
public static final String PREFS_NAME = "PRODUCT_APP";
public static final String FAVORITES = "Product_Favorite";
/*Added*/
private static RecyclerViewClickListener listener;
public RecyclerViewClickListener getListener() {
return listener;
}
public void setListener(RecyclerViewClickListener listener) {
SharedPreference.listener = listener;
}
/*Added*/
...
}
Add this code to MainActivity & Favourite Activity 'OnCreate' method
sharedPreference.setListener(this);
public class MainActivity extends AppCompatActivity implements RecyclerViewClickListener{
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
sharedPreference.setListener(this);
....
}
public class Favourite extends AppCompatActivity implements RecyclerViewClickListener{
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_favourite);
sharedPreference.setListener(this);
....
}
Change Adapter 'OnClick method' to
#Override
public void onClick(View v) {
notifyDataSetChanged();
itemListener = sharedPreference.getListener();
itemListener.recyclerViewListClicked(v, this.getLayoutPosition());
}
And Finally change in MainActivity 'resume' method
#Override
protected void onResume() {
super.onResume();
sharedPreference.setListener(this);
da.notifyDataSetChanged();
}
Hope it helps.!

In your DiseaseAdapterViewHolder change the onclick methode to,
#Override
public void onClick(View v) {
itemListener.recyclerViewListClicked(v, this.getLayoutPosition());
notifyDataSetChanged();
}

Develop Reference

Java is a programming language and computing platform first released by Sun Microsystems in 1995.

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