Develop Reference

Listener from DialogFragment to Fragment

I'm a beginner in Java and I'm trying to create a listener in my DialogFragment to notice my fragment that some book was removed. When the user removes a book, I want to call the removeBook method in BookFragment and update the recyclerview.
Here is my BookDialogFragment.java:
package com.compose.dietapp.ui.books;
import android.app.Dialog;
import android.content.DialogInterface;
import android.graphics.Color;
import android.os.Bundle;
import android.util.Log;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AlertDialog;
import androidx.fragment.app.DialogFragment;
import java.util.Objects;
public class BookDialogFragment extends DialogFragment {
private final String nameToDelete;
private final int position;
private static String MESSAGE_TO_DIALOG_FRAGMENT;
public BookDialogFragment(String nameToDelete, int position) {
this.nameToDelete = nameToDelete;
this.position = position;
}
public static BookDialogFragment newInstance(String title, String nameToDelete, int position) {
BookDialogFragment frag = new BookDialogFragment(nameToDelete, position);
if (Objects.equals(nameToDelete, "none")) {
MESSAGE_TO_DIALOG_FRAGMENT = "Book removed!";
} else {
MESSAGE_TO_DIALOG_FRAGMENT = "Are you sure you want to remove the book '"
+ nameToDelete
+ "'?";
}
Bundle args = new Bundle();
args.putString("title", title);
frag.setArguments(args);
return frag;
}
#NonNull
#Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
assert getArguments() != null;
String title = getArguments().getString("title");
AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(getActivity());
alertDialogBuilder.setTitle(title);
alertDialogBuilder.setMessage(MESSAGE_TO_DIALOG_FRAGMENT);
if (Objects.equals(MESSAGE_TO_DIALOG_FRAGMENT, "Book removed!")) {
alertDialogBuilder.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
if (dialog != null) {
dialog.dismiss();
}
}
});
} else {
alertDialogBuilder.setPositiveButton("Remove", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
// here I want to callback my fragment
BookFragment deleteBook = new BookFragment();
deleteBook.removeBook(nameToDelete, position);
Bundle result = new Bundle();
result.putBoolean("value", true);
getParentFragmentManager().setFragmentResult("removed", result);
}
});
alertDialogBuilder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
if (dialog != null) {
dialog.dismiss();
}
}
});
}
return alertDialogBuilder.create();
}
#Override
public void onStart() {
super.onStart();
((AlertDialog) Objects.requireNonNull(getDialog())).getButton(AlertDialog.BUTTON_NEGATIVE)
.setTextColor(Color.rgb(128, 128, 128));
}
}
And here is my BookFragment.java:
package com.compose.dietapp.ui.books;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import com.compose.dietapp.R;
import com.compose.dietapp.database.DatabaseAccess;
import com.compose.dietapp.databinding.FragmentBookBinding;
import java.util.ArrayList;
public class BookFragment extends Fragment{
#SuppressLint("StaticFieldLeak")
private static Activity activity;
private RecyclerView recyclerView;
private final ArrayList<Book> itensBook = new ArrayList<Book>();
private BookAdapter bookAdapter;
public View onCreateView(#NonNull LayoutInflater inflater,
ViewGroup container, Bundle savedInstanceState) {
activity = this.getActivity();
View v = inflater.inflate(R.layout.fragment_book, container, false);
recyclerView = (RecyclerView) v.findViewById(R.id.book_recycler);
instanciateBooks();
return v;
}
private void instanciateBooks() {
ArrayList<ArrayList<String>> bookDatabaseValues = getDatabaseData();
if (recyclerView != null && bookDatabaseValues != null) {
createItemBook(bookDatabaseValues);
createRecyclerViewBook();
}
}
public void removeBook(String nameToDelete, int position) {
getChildFragmentManager().setFragmentResultListener("removed",
this, new FragmentResultListener() {
#Override
public void onFragmentResult(#NonNull String requestKey, #NonNull Bundle bundle) {
String result = bundle.getString("value");
Log.i("result", result);
}
});
}
private void createRecyclerViewBook() {
recyclerView.setHasFixedSize(true);
bookAdapter = new BookAdapter(activity, itensBook);
RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(activity,
LinearLayoutManager.VERTICAL, false);
recyclerView.setLayoutManager(layoutManager);
recyclerView.setAdapter(bookAdapter);
}
private void createItemBook(ArrayList<ArrayList<String>> bookDatabaseValues) {
for (int i = 0; i < bookDatabaseValues.size(); i++) {
itensBook.add(new Book(
String.valueOf(bookDatabaseValues.get(i).get(0)),
String.valueOf(bookDatabaseValues.get(i).get(1)),
String.valueOf(bookDatabaseValues.get(i).get(2)),
String.valueOf(bookDatabaseValues.get(i).get(3)),
String.valueOf(bookDatabaseValues.get(i).get(4))
));
}
}
public static ArrayList<ArrayList<String>> getDatabaseData() {
if (activity != null) {
return getArrayListsFromDatabase();
}
return null;
}
private static ArrayList<ArrayList<String>> getArrayListsFromDatabase() {
DatabaseAccess databaseAccess = openDatabase();
ArrayList<ArrayList<String>> books = databaseAccess.getBook();
closeDatabase(databaseAccess);
return books;
}
private static void closeDatabase(DatabaseAccess databaseAccess) {
databaseAccess.close();
}
#NonNull
private static DatabaseAccess openDatabase() {
DatabaseAccess databaseAccess = DatabaseAccess.getInstance(activity);
databaseAccess.open();
return databaseAccess;
}
}
Here is my BookAdapter.java:
package com.compose.dietapp.ui.books;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.FragmentManager;
import androidx.recyclerview.widget.RecyclerView;
import com.compose.dietapp.R;
import java.io.InputStream;
import java.util.ArrayList;
public class BookAdapter extends RecyclerView.Adapter<BookViewHolder> {
public static FragmentManager supportFragment;
private final Context context;
private final ArrayList<Book> itens;
public BookAdapter(Context context, ArrayList<Book> itens) {
this.context = context;
this.itens = itens;
}
#NonNull
#Override
public BookViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(context).inflate(R.layout.item_recycler_book, parent, false);
BookViewHolder viewHolder = new BookViewHolder(view);
supportFragment = ((AppCompatActivity)context).getSupportFragmentManager();
return viewHolder;
}
#Override
public void onBindViewHolder(#NonNull BookViewHolder bookViewHolder, int position) {
Book book = itens.get(position);
bookViewHolder.nome.setText(book.getName());
bookViewHolder.bookType.setText(book.getBookType());
imageInstanciate(bookViewHolder);
}
private void imageInstanciate(#NonNull BookViewHolder bookViewHolder) {
new DownloadImageFromInternet((ImageView) bookViewHolder.bookImage)
.execute("https://pbs.twimg.com/profile_images/630285593268752384/iD1MkFQ0.png");
}
private class DownloadImageFromInternet extends AsyncTask<String, Void, Bitmap> {
ImageView imageView;
public DownloadImageFromInternet(ImageView imageView) {
this.imageView = imageView;
}
protected Bitmap doInBackground(String... urls) {
String imageURL = urls[0];
Bitmap bimage = null;
try {
InputStream in = new java.net.URL(imageURL).openStream();
bimage = BitmapFactory.decodeStream(in);
} catch (Exception e) {
Log.e("Error Message", e.getMessage());
e.printStackTrace();
}
return bimage;
}
protected void onPostExecute(Bitmap result) {
imageView.setImageBitmap(result);
}
}
#Override
public int getItemCount() {
return itens.size();
}
}
Here is my BookViewHolder.java:
package com.compose.dietapp.ui.books;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.fragment.app.FragmentManager;
import androidx.recyclerview.widget.RecyclerView;
import com.compose.dietapp.R;
public class BookViewHolder extends RecyclerView.ViewHolder {
TextView nome;
TextView bookType;
ImageView bookImage;
public BookViewHolder(#NonNull View itemView) {
super(itemView);
nome = itemView.findViewById(R.id.nome);
bookType = itemView.findViewById(R.id.email);
bookImage = itemView.findViewById(R.id.book_image);
itemView.setOnLongClickListener(new View.OnLongClickListener() {
#Override
public boolean onLongClick(View view) {
int position = getLayoutPosition();
return true;
}
});
itemView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
String nomeDelete = nome.getText().toString();
int position = getLayoutPosition();
FragmentManager fm = BookAdapter.supportFragment;
BookDialogFragment bookDialogFragment =
BookDialogFragment.newInstance("Atenção:", nomeDelete, position);
bookDialogFragment.show(fm, "fragment_alert");
}
});
}
}
I've seen other similar solutions, but I didn't get to implement them in my code. Can anyone help me?

Going through your code, it doesn't seem like you're using Navigation Component. So let's do it this way.
Your BookDialogFragment is a child fragment to BookFragment. So basically, you should set a result in your dialog when remove button is clicked. Then set up a result listener code in you parent fragment (BookFragment), so as to get immediate result to act upon.
First part, set a result when remove is clicked
NonNull
#Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
...
if (Objects.equals(MESSAGE_TO_DIALOG_FRAGMENT, "Book removed!")) {
...
} else {
alertDialogBuilder.setPositiveButton("Remove", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
// here I want to callback my fragment
BookFragment deleteBook = new BookFragment();
deleteBook.removeBook(nameToDelete, position);
Bundle result = new Bundle();
result.putBoolean("value", true);
getParentFragmentManager().setFragmentResult("removed", result);
}
});
alertDialogBuilder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
...
}
}
}
Then, listen for and act on the result in you BookFragment, wherever you want to, with these lines.
getChildFragmentManager().setFragmentResultListener("removed", this, new FragmentResultListener() {
#Override
public void onFragmentResult(#NonNull String requestKey, #NonNull Bundle bundle) {
// We use a Boolean here, but any type that can be put in a Bundle is supported
Boolean result = bundle.getString("value");
// Do something with the result
}
});
PS: You can use constant variables where you have "removed" and "value" for accuracy.
Hope this helps :)

CustomAdapter.MyHeadingViewHolder' is not within its bound; should extend 'android.support.v7.widget.RecyclerView.ViewHolder' Error

I have a android studio project and use 'com.timehop.stickyheadersrecyclerview:library:0.4.3#aar'
library it works fine but when I create a new project using same code It show me the following error in line 26 StickyRecyclerHeadersAdapter<CustomAdapter.MyHeadingViewHolder> { of CustomAdapter class:
Type parameter 'com.vatexpress.service.CustomAdapter.MyHeadingViewHolder' is not within its bound; should extend 'android.support.v7.widget.RecyclerView.ViewHolder'
and also show me following error in line 75 recyclerView.addItemDecoration(new StickyRecyclerHeadersDecoration(customAdapter));of ManinActivity class:
Type parameter 'com.vatexpress.service.CustomAdapter.MyHeadingViewHolder' is not within its bound; should extend 'android.support.v7.widget.RecyclerView.ViewHolder'
Here is my CustomAdapter class:
package com.vatexpress.service;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.Filter;
import android.widget.Filterable;
import android.widget.LinearLayout;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;
import com.timehop.stickyheadersrecyclerview.StickyRecyclerHeadersAdapter;
import java.util.ArrayList;
public class CustomAdapter extends RecyclerView.Adapter<CustomAdapter.MyChildViewHolder>
implements Filterable,
StickyRecyclerHeadersAdapter<CustomAdapter.MyHeadingViewHolder> {
private Context context;
private Activity activity;
private ArrayList<Model> dataholder;
ArrayList<Model> backup;
MyDatabaseHelper obj = null;
String code, nature, name, sd, vat, vds, vat_ref, vds_ref, about;
public static final int CHILD_LIST = 1;
public static final int HEADER = 2;
CustomAdapter(Activity activity, Context context, ArrayList<Model> dataholder){
this.activity = activity;
this.context = context;
this.dataholder = dataholder;
backup=new ArrayList<>(dataholder);
}
#NonNull
#Override
public MyChildViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
LayoutInflater inflater = LayoutInflater.from(context);
View view = inflater.inflate(R.layout.my_row, parent, false);
return new MyChildViewHolder(view);
}
#Override
public void onBindViewHolder(#NonNull final MyChildViewHolder holder, final int position) {
// if (holder instanceof MyChildViewHolder) {
final Model temp=dataholder.get(position);
holder.service_code.setText(dataholder.get(position).getService_code());
holder.service_name.setText(dataholder.get(position).getService_name());
//Recyclerview onClickListener
holder.mainLayout.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent = new Intent(context, DetailActivity.class);
obj = new MyDatabaseHelper(context);
Cursor cursor = obj.getData(temp.id);
if (cursor != null) {
if (cursor.moveToFirst()) {
do {
code = cursor.getString(0);
nature = cursor.getString(2);
name = cursor.getString(1);
sd = cursor.getString(3);
vat = cursor.getString(4);
vds = cursor.getString(5);
vat_ref = cursor.getString(6);
vds_ref = cursor.getString(7);
about = cursor.getString(8);
} while (cursor.moveToNext());
}
}
intent.putExtra("code", code);
intent.putExtra("nature", nature);
intent.putExtra("servicename", name);
intent.putExtra("sd", sd);
intent.putExtra("vat", vat);
intent.putExtra("vds", vds);
intent.putExtra("vat_ref", vat_ref);
intent.putExtra("vds_ref", vds_ref);
intent.putExtra("about", about);
activity.startActivityForResult(intent, 1);
}
});
// }
// else if(holder instanceof MyHeadingViewHolder) {
// MyHeadingViewHolder myHeadingViewHolder = (MyHeadingViewHolder) holder;
// myHeadingViewHolder.heading.setText(dataholder.get(position).service_heading);
// }
}
#Override
public long getHeaderId(int position) {
return dataholder.get(position).getSection();
}
#Override
public MyHeadingViewHolder onCreateHeaderViewHolder(ViewGroup parent) {
LayoutInflater inflater = LayoutInflater.from(context);
View view = inflater.inflate(R.layout.heading_layout, parent, false);
return new MyHeadingViewHolder(view);
}
#Override
public void onBindHeaderViewHolder(MyHeadingViewHolder myHeadingViewHolder, int i) {
myHeadingViewHolder.heading.setText(dataholder.get(i).getService_heading());
}
#Override
public int getItemCount() {
return dataholder.size();
}
#Override
public Filter getFilter() {
return filter;
}
Filter filter=new Filter() {
#Override
// background thread
protected FilterResults performFiltering(CharSequence keyword)
{
ArrayList<Model> filtereddata=new ArrayList<>();
if(keyword.toString().isEmpty())
filtereddata.addAll(backup);
else
{
for(Model obj : backup)
{
if(obj.getService_name().toString().toLowerCase().contains(keyword.toString().toLowerCase()))
filtereddata.add(obj);
}
}
FilterResults results=new FilterResults();
results.values=filtereddata;
return results;
}
#Override // main UI thread
protected void publishResults(CharSequence constraint, FilterResults results)
{
dataholder.clear();
dataholder.addAll((ArrayList<Model>)results.values);
notifyDataSetChanged();
}
};
// #Override
// public int getItemViewType(int position) {
// if (dataholder.get(position).typeHeading)
// {
// return HEADER;
// }
// else {
// return CHILD_LIST;
// }
// }
class MyChildViewHolder extends RecyclerView.ViewHolder {
TextView service_code, service_name;
LinearLayout mainLayout;
MyChildViewHolder(#NonNull View itemView) {
super(itemView);
service_code = itemView.findViewById(R.id.service_code);
service_name = itemView.findViewById(R.id.service_name);
mainLayout = itemView.findViewById(R.id.mainLayout);
//Animate Recyclerview
Animation translate_anim = AnimationUtils.loadAnimation(context, R.anim.translate_anim);
mainLayout.setAnimation(translate_anim);
}
}
class MyHeadingViewHolder extends RecyclerView.ViewHolder {
TextView heading;
public MyHeadingViewHolder(#NonNull View itemView) {
super(itemView);
heading = itemView.findViewById(R.id.heading_name);
}
}
}
Here is my MainActivity class:
package com.vatexpress.service;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import android.content.DialogInterface;
import android.content.Intent;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.speech.RecognizerIntent;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.ContextMenu;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.SearchView;
import android.widget.TextView;
import android.widget.Toast;
import com.timehop.stickyheadersrecyclerview.StickyRecyclerHeadersDecoration;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Locale;
public final class MainActivity extends AppCompatActivity {
private static final int REQUEST_CODE_SPEECH_INPUT =1000 ;
RecyclerView recyclerView;
TextView noSearchResultsFoundText;
EditText editText;
ImageView clearQueryImageView ;
ImageView voiceSearchImageView;
MyDatabaseHelper myDB;
ArrayList<Model> dataholder;
CustomAdapter customAdapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
recyclerView = findViewById(R.id.search_list);
noSearchResultsFoundText = findViewById(R.id.no_search_results_found_text);
myDB = new MyDatabaseHelper(MainActivity.this);
try {
myDB.createDataBase();
} catch (IOException ioe) {
throw new Error("Unable to create database");
}
try {
myDB.openDataBase();
} catch (SQLException sqle) {
throw sqle;
}
storeDataInArrays();
recyclerView.setLayoutManager(new LinearLayoutManager(this));
customAdapter = new CustomAdapter(MainActivity.this,this, dataholder);
recyclerView.setAdapter(customAdapter);
recyclerView.addItemDecoration(new StickyRecyclerHeadersDecoration(customAdapter));
editText = (EditText) findViewById(R.id.search_edit_text);
editText.addTextChangedListener(new TextWatcher() {
public void afterTextChanged(Editable s) {
}
public void beforeTextChanged(CharSequence s, int start, int count, int after) {}
public void onTextChanged(CharSequence s, int start, int before, int count) {
customAdapter.getFilter().filter(s.toString());
if (editText.getText().toString().isEmpty()){
clearQueryImageView.setVisibility(View.GONE);
voiceSearchImageView.setVisibility(View.VISIBLE);
}else{
clearQueryImageView.setVisibility(View.VISIBLE);
voiceSearchImageView.setVisibility(View.GONE);
}
}
});
voiceSearchImageView = findViewById(R.id.voice_search_query);
//button clic to show speech to text dilog
voiceSearchImageView.setOnClickListener( new View.OnClickListener() {
#Override
public void onClick(View v) {
speak();
}
} );
clearQueryImageView = findViewById(R.id.clear_search_query);
clearQueryImageView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
editText.setText("");
}
});
}
private void speak() {
//intent is show speech to text dialog
Intent intent= new Intent( RecognizerIntent.ACTION_RECOGNIZE_SPEECH );
intent.putExtra( RecognizerIntent.EXTRA_LANGUAGE_MODEL,
RecognizerIntent.LANGUAGE_MODEL_FREE_FORM);
intent.putExtra( RecognizerIntent.EXTRA_LANGUAGE, Locale.getDefault() );
intent.putExtra( RecognizerIntent.EXTRA_PROMPT, "HI speak something" );
// Start intent
try {
//in there was no errror
//show dilog
startActivityForResult( intent, REQUEST_CODE_SPEECH_INPUT);
}
catch(Exception e){
//show messageof error and show
Toast.makeText( this,""+e.getMessage(), Toast.LENGTH_SHORT ).show();
}
}
//recive voice input and handle it
#Override
protected void onActivityResult(int requestCode, int resultCode, #Nullable Intent data) {
super.onActivityResult( requestCode, resultCode, data );
switch (requestCode){
case REQUEST_CODE_SPEECH_INPUT:{
if(resultCode==RESULT_OK && null!=data){
//get text arry form voice intent
ArrayList<String> result=data.getStringArrayListExtra( RecognizerIntent.EXTRA_RESULTS );
//set to text view
editText.setText( result.get( 0 ) );
}
break;
}
}
}
public void storeDataInArrays(){
dataholder = new ArrayList<>();
String code = "";
boolean firstTime = true;
int section = 0, count = 0;
Cursor cursor = myDB.readAllData();
if(cursor.getCount() == 0){
noSearchResultsFoundText.setVisibility(View.VISIBLE);
}else{
while (cursor.moveToNext()){
if (firstTime) {
code = cursor.getString(1);
Model obj=new Model(cursor.getString(0),cursor.getString(1), cursor.getString(2), cursor.getString(3), true, section);
firstTime = false;
dataholder.add(obj);
}
else
{
if (!code.equals(cursor.getString(1))) {
section = count;
Model obj=new Model(cursor.getString(0),cursor.getString(1), cursor.getString(2), cursor.getString(3), true, section);
dataholder.add(obj);
code = cursor.getString(1);
}
else
{
Model obj=new Model(cursor.getString(0),cursor.getString(1), cursor.getString(2), cursor.getString(3), false, section);
dataholder.add(obj);
}
}
count++;
}
noSearchResultsFoundText.setVisibility(View.GONE);
}
}
}
Please gives me solution how can I solve this!

IndexOutOfBoundsException when making one Arraylist equal to another

I am trying to filter my RecyclerView using SearchView by following this guide: https://www.geeksforgeeks.org/searchview-in-android-with-recyclerview/
However, I am getting an IndexOutOfBoundsException when making one Arraylist equal to another, which I believe is happening at this portion of the code here:
public void filterList(ArrayList filteredlist) {
// below line is to add our filtered
// list in our course array list.
book_title = filteredlist;
// below line is to notify our adapter
// as change in recycler view data.
notifyDataSetChanged();
}
Here is the full code for my adapter class:
package com.benjamin.kwok.recipertracker;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.os.Build;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.LinearLayout;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.annotation.RequiresApi;
import androidx.recyclerview.widget.RecyclerView;
import java.util.ArrayList;
public class CustomAdapter extends RecyclerView.Adapter<CustomAdapter.MyViewHolder> {
private Context context;
private Activity activity;
private ArrayList book_id, book_title, book_author, book_pages;
CustomAdapter(Activity activity, Context context, ArrayList book_id, ArrayList book_title, ArrayList book_author,
ArrayList book_pages){
this.activity = activity;
this.context = context;
this.book_id = book_id;
this.book_title = book_title;
this.book_author = book_author;
this.book_pages = book_pages;
}
public void filterList(ArrayList filteredlist) {
// below line is to add our filtered
// list in our course array list.
book_title = filteredlist;
// below line is to notify our adapter
// as change in recycler view data.
notifyDataSetChanged();
}
#NonNull
#Override
public MyViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
LayoutInflater inflater = LayoutInflater.from(context);
View view = inflater.inflate(R.layout.my_row, parent, false);
return new MyViewHolder(view);
}
#RequiresApi(api = Build.VERSION_CODES.M)
#Override
public void onBindViewHolder(#NonNull final MyViewHolder holder, final int position) {
holder.book_title_txt.setText(String.valueOf(book_title.get(position)));
holder.book_author_txt.setText(String.valueOf(book_author.get(position)));
holder.book_pages_txt.setText(String.valueOf(book_pages.get(position)));
//Recyclerview onClickListener
holder.mainLayout.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent = new Intent(context, UpdateActivity.class);
intent.putExtra("id", String.valueOf(book_id.get(position)));
intent.putExtra("title", String.valueOf(book_title.get(position)));
intent.putExtra("author", String.valueOf(book_author.get(position)));
intent.putExtra("pages", String.valueOf(book_pages.get(position)));
activity.startActivityForResult(intent, 1);
}
});
}
#Override
public int getItemCount() {
return book_id.size();
}
class MyViewHolder extends RecyclerView.ViewHolder {
TextView book_id_txt, book_title_txt, book_author_txt, book_pages_txt;
LinearLayout mainLayout;
MyViewHolder(#NonNull View itemView) {
super(itemView);
book_title_txt = itemView.findViewById(R.id.recipe_title_txt);
book_author_txt = itemView.findViewById(R.id.book_description_txt);
book_pages_txt = itemView.findViewById(R.id.recipe_pages_txt);
mainLayout = itemView.findViewById(R.id.mainLayout);
//Animate Recyclerview
Animation translate_anim = AnimationUtils.loadAnimation(context, R.anim.translate_anim);
mainLayout.setAnimation(translate_anim);
}
}
}
And the full code for my MainActivity:
package com.benjamin.kwok.recipertracker;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.SearchView;
import androidx.core.app.ActivityCompat;
import androidx.core.content.FileProvider;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import android.Manifest;
import android.app.Activity;
import android.content.ContentValues;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.pm.PackageManager;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.drawable.BitmapDrawable;
import android.media.MediaScannerConnection;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.preference.PreferenceManager;
import android.provider.MediaStore;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import com.google.android.material.floatingactionbutton.FloatingActionButton;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
public class MainActivity extends AppCompatActivity {
RecyclerView recyclerView;
FloatingActionButton add_button;
FloatingActionButton camera_button;
ImageView empty_imageview;
ImageView imageView;
TextView no_data;
MyDatabaseHelper myDB;
ArrayList<String> recipe_id, recipe_title, recipe_description, recipe_minutes;
CustomAdapter customAdapter;
final static private int NEW_PICTURE = 1;
private String mCameraFileName;
private static final String TAG = "CapturePicture";
static final int REQUEST_PICTURE_CAPTURE = 1;
private String pictureFilePath;
private String deviceIdentifier;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},1);
ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE},1);
// SharedPreferences mSharedPreference= PreferenceManager.getDefaultSharedPreferences(this);
// SharedPreferences.Editor editor = mSharedPreference.edit();
// String text= mSharedPreference.getString(getString(R.string.name), "");
//// name_output.setText(text);
recyclerView = findViewById(R.id.recyclerView);
add_button = findViewById(R.id.add_button);
camera_button = findViewById(R.id.camera_button);
empty_imageview = findViewById(R.id.empty_imageview);
imageView = findViewById(R.id.imageView);
no_data = findViewById(R.id.no_data);
add_button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent = new Intent(MainActivity.this, AddActivity.class);
startActivity(intent);
}
});
camera_button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
startActivityForResult(intent, 100);
}
});
myDB = new MyDatabaseHelper(MainActivity.this);
recipe_id = new ArrayList<>();
recipe_title = new ArrayList<>(10);
recipe_description = new ArrayList<>();
recipe_minutes = new ArrayList<>();
storeDataInArrays();
customAdapter = new CustomAdapter(MainActivity.this,this, recipe_id, recipe_title, recipe_description,
recipe_minutes);
recyclerView.setAdapter(customAdapter);
recyclerView.setLayoutManager(new LinearLayoutManager(MainActivity.this));
loadData();
}
protected void onActivityResult(int requestCode, int resultCode, #Nullable Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == 100) {
Bundle bundle = data.getExtras();
Bitmap captureImage = (Bitmap) bundle.get("data");
imageView.setImageBitmap(captureImage);
saveToGallery();
}
if(resultCode == RESULT_OK){
Toast.makeText(this, "Image added to Gallery", Toast.LENGTH_LONG);
}
}
private void saveToGallery(){
BitmapDrawable draw = (BitmapDrawable) imageView.getDrawable();
Bitmap bitmap = draw.getBitmap();
FileOutputStream outStream = null;
File sdCard = Environment.getExternalStorageDirectory();
File dir = new File(sdCard.getAbsolutePath() + "/RecipeImages");
dir.mkdirs();
String fileName = String.format("%d.jpg", System.currentTimeMillis());
File outFile = new File(dir, fileName);
MediaScannerConnection.scanFile(this, new String[] { outFile.getPath() }, new String[] { "image/jpeg" }, null);
try {
outStream = new FileOutputStream(outFile);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, outStream);
try {
outStream.flush();
} catch (IOException e) {
e.printStackTrace();
}
try {
outStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
void storeDataInArrays(){
Cursor cursor = myDB.readAllData();
if(cursor.getCount() == 0){
empty_imageview.setVisibility(View.VISIBLE);
no_data.setVisibility(View.VISIBLE);
}else{
while (cursor.moveToNext()){
recipe_id.add(cursor.getString(0));
recipe_title.add(cursor.getString(1));
recipe_description.add(cursor.getString(2));
recipe_minutes.add(cursor.getString(3));
}
empty_imageview.setVisibility(View.GONE);
no_data.setVisibility(View.GONE);
}
}
public void loadData() {
SharedPreferences mPreferences = PreferenceManager.getDefaultSharedPreferences(this);
String name = mPreferences.getString("name","");
setTitle(name+"'s" + " Recipe Tracker");
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.my_menu, menu);
// return super.onCreateOptionsMenu(menu);
MenuItem searchItem = menu.findItem(R.id.actionSearch);
// getting search view of our item.
SearchView searchView = (SearchView) searchItem.getActionView();
// below line is to call set on query text listener method.
searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
#Override
public boolean onQueryTextSubmit(String query) {
return false;
}
#Override
public boolean onQueryTextChange(String newText) {
// inside on query text change method we are
// calling a method to filter our recycler view.
filter(newText);
return false;
}
});
return true;
}
private void filter(String text) {
// creating a new array list to filter our data.
ArrayList filteredlist = new ArrayList<>();
// running a for loop to compare elements.
for (String item : recipe_title) {
// checking if the entered string matched with any item of our recycler view.
if (item.toLowerCase().contains(text.toLowerCase())) {
// if the item is matched we are
// adding it to our filtered list.
filteredlist.add(item);
}
}
if (filteredlist.isEmpty()) {
// if no item is added in filtered list we are
// displaying a toast message as no data found.
Toast.makeText(this, "No Data Found..", Toast.LENGTH_SHORT).show();
} else {
// at last we are passing that filtered
// list to our adapter class.
customAdapter.filterList(filteredlist);
}
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
if(item.getItemId() == R.id.delete_all){
confirmDialog();
}
return super.onOptionsItemSelected(item);
}
void confirmDialog(){
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("Delete All?");
builder.setMessage("Are you sure you want to delete all Data?");
builder.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
MyDatabaseHelper myDB = new MyDatabaseHelper(MainActivity.this);
myDB.deleteAllData();
//Refresh Activity
Intent intent = new Intent(MainActivity.this, MainActivity.class);
startActivity(intent);
finish();
}
});
builder.setNegativeButton("No", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
}
});
builder.create().show();
}
}
As soon as I start typing in a new search query, this error seems to get thrown.

How i can download and read "PDF file" with AsyncTask

I am creating an application for School Students so that they do not miss their huge BOOKS. In this project, the student clicks “RecylerView”, immediately downloads the book “Pdf” and saves it to external storage. "like whatsapp" without database
At the moment, I have a problem in that it only sees the file, but does not save!
I am using AsyscTask "My PDF Viewer" activity which bottom
please help!!!
My Main Activity
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.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.RelativeLayout;
import java.util.ArrayList;
import java.util.List;
> public class MainActivity extends AppCompatActivity {
List<Product> productList;
//the recyclerview
RecyclerView recyclerView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Animation animation = AnimationUtils.loadAnimation(this, R.anim.anim_about_card_show);
RelativeLayout relativeLayout = findViewById(R.id.rl);
relativeLayout.startAnimation(animation);
//getting the recyclerview from xml
recyclerView = (RecyclerView) findViewById(R.id.recyclerView);
recyclerView.setHasFixedSize(true);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
//initializing the productlist
productList = new ArrayList<>();
//adding some items to our list
productList.add(
new Product(
1,
"TEst 11111 \n",
60000,
R.drawable.android,
"link1"
));
productList.add(
new Product(
1,
" More types, Methods, Conditionals \n",
60000,
R.drawable.android,
"link2"
));
productList.add(
new Product(
1,
"Loops, Arrays ",
60000,
R.drawable.android,
"lin3"
));
productList.add(
new Product(
1,
"Strings",
60000,
R.drawable.android,
"https://firebasestorage.googleapis.com/v0/b/firepdf-4c1d6.appspot.com/o/2.intro.pdf?alt=media&token=75731b04-c1e7-42c4-b988-e50a8f7e5f6b "
));
//creating recyclerview adapter
ProductAdapter adapter = new ProductAdapter(this, productList);
//setting adapter to recyclerview
recyclerView.setAdapter(adapter);
}
}
Adapter
import android.content.Context;
import android.content.Intent;
import android.net.Uri;
import android.support.v7.widget.CardView;
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 java.util.List;
> public class ProductAdapter extends RecyclerView.Adapter<ProductAdapter.ProductViewHolder> {
//this context we will use to inflate the layout
private Context mCtx;
//we are storing all the products in a list
private List<Product> productList;
//getting the context and product list with constructor
public ProductAdapter(Context mCtx, List<Product> productList) {
this.mCtx = mCtx;
this.productList = productList;
}
#Override
public ProductViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
//inflating and returning our view holder
LayoutInflater inflater = LayoutInflater.from(mCtx);
View view = inflater.inflate(R.layout.layout_products, null);
return new ProductViewHolder(view);
}
#Override
public void onBindViewHolder(ProductViewHolder holder, final int position) {
//getting the product of the specified position
final Product product = productList.get(position);
//binding the data with the viewholder views
holder.textViewTitle.setText(product.getTitle());
holder.imageView.setImageDrawable(mCtx.getResources().getDrawable(product.getImage()));
holder.cardView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent i = new Intent(v.getContext(), pdf.class);
i.putExtra("title",productList.get(position).getTitle());
i.putExtra("product",productList.get(position).getTitle());
i.putExtra("link",productList.get(position).getLink());
mCtx.startActivity(i);
}
});
}
#Override
public int getItemCount() {
return productList.size();
}
class ProductViewHolder extends RecyclerView.ViewHolder {
TextView textViewTitle;
ImageView imageView;
CardView cardView;
public ProductViewHolder(View itemView) {
super(itemView);
cardView = itemView.findViewById(R.id.cardview);// card intial
textViewTitle = itemView.findViewById(R.id.textViewTitle);
imageView = itemView.findViewById(R.id.imageView);
}
}
}
My Pdf Viewer
import android.app.ProgressDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.MenuItem;
import android.widget.Toast;
import com.github.barteksc.pdfviewer.PDFView;
import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
public class pdf extends AppCompatActivity {
String link="",productList="",product="";
PDFView pdfView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_pdf);
product =getIntent().getStringExtra("title");
productList=getIntent().getStringExtra("productList");
link=getIntent().getStringExtra("link");
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setDisplayShowHomeEnabled(true);
getSupportActionBar().setTitle(productList);
pdfView=findViewById(R.id.pdfv);
//pdfView.fromAsset(link).load();
if (isConnected()) {
Toast.makeText(getApplicationContext(), "Internet Connected", Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(getApplicationContext(), "No Internet Connection", Toast.LENGTH_SHORT).show();
AlertDialog.Builder builder = new AlertDialog.Builder(pdf.this);
builder.setTitle("NoInternet Connection Alert")
.setMessage("GO to Setting ?")
.setCancelable(false)
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
startActivity(new Intent(android.provider.Settings.ACTION_WIRELESS_SETTINGS));
}
})
.setNegativeButton("No", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
Toast.makeText(pdf.this,"Go Back TO HomePage!",Toast.LENGTH_SHORT).show();
}
});
//Creating dialog box
AlertDialog dialog = builder.create();
dialog.show();
}
Bundle bundle = getIntent().getExtras();
if (bundle != null) {
link = getIntent().getStringExtra("link");
}
new pdf.RetrievePDFStream().execute(link);
}
public boolean isConnected() {
boolean connected = false;
try {
ConnectivityManager cm = (ConnectivityManager)getApplicationContext().getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo nInfo = cm.getActiveNetworkInfo();
connected = nInfo != null && nInfo.isAvailable() && nInfo.isConnected();
return connected;
} catch (Exception e) {
Log.e("Connectivity Exception", e.getMessage());
}
return connected;
}
class RetrievePDFStream extends AsyncTask<String, Void, InputStream> {
ProgressDialog progressDialog;
protected void onPreExecute()
{
progressDialog = new ProgressDialog(pdf.this);
progressDialog.setTitle("getting the book content...");
progressDialog.setMessage("Please wait...");
progressDialog.setCanceledOnTouchOutside(false);
progressDialog.show();
}
#Override
protected InputStream doInBackground(String... strings) {
InputStream inputStream = null;
try {
URL urlx = new URL(strings[0]);
HttpURLConnection urlConnection = (HttpURLConnection) urlx.openConnection();
if (urlConnection.getResponseCode() == 200) {
inputStream = new BufferedInputStream(urlConnection.getInputStream());
}
} catch (IOException e) {
return null;
}
return inputStream;
}
#Override
protected void onPostExecute(InputStream inputStream) {
pdfView.fromStream(inputStream).load();
progressDialog.dismiss();
}
}
#Override public boolean onOptionsItemSelected(MenuItem item)
{
if (item.getItemId() == android.R.id.home)//means home default hai kya yesok
{
onBackPressed();
return true;
}
return false;
}
}

How to refresh or update a fragment after deleting from the database

I am new to android development, and i'm trying to build a simple hymn book,
I'm using bottom navigation, i use fragments on each tab to display numbers and titles of each hymn.
In my favourite fragments i have a list of favourite songs displayed using recycler view fetch from the database.
I use on long click listener to delete songs from the favorite table in the database, but any time i delete a
song my favorite fragment doesn't get refreshed or undated with current items. Please, how can I refresh or update
my favourite fragment anytime i delete a song. thank you!
'''Favourite Adapter''
import android.app.FragmentManager;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.database.sqlite.SQLiteDatabase;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.RelativeLayout;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
import static android.content.Context.MODE_PRIVATE;
public class FavouriteAdapter extends RecyclerView.Adapter<FavouriteAdapter.ViewHolder> {
private Context favContext;
private ArrayList<String> favNumbers = new ArrayList<>();
private ArrayList<String> favTitles = new ArrayList<>();
public FavouriteAdapter(Context favContext, ArrayList<String> favNumbers, ArrayList<String> favTitles) {
this.favContext = favContext;
this.favNumbers = favNumbers;
this.favTitles = favTitles;
}
#Override
public FavouriteAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.favourite_list_items, parent, false);
return new ViewHolder(v);
}
#Override
public void onBindViewHolder(final FavouriteAdapter.ViewHolder holder, final int position) {
holder.textViewFavNum.setText(favNumbers.get(position));
holder.textViewFavTitle.setText(favTitles.get(position));
final String hymn_no = favNumbers.get(position);
holder.itemView.setTag(favNumbers.get(position));
holder.favParentLayout.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent i;
i = new Intent(view.getContext(), Songs.class);
i.putExtra("numId", favNumbers.get(position));
i.putExtra("titleName", favTitles.get(position));
favContext.startActivity(i);
}
});
holder.favParentLayout.setOnLongClickListener(new View.OnLongClickListener() {
#Override
public boolean onLongClick(final View view) {
new AlertDialog.Builder(view.getContext())
.setIcon(android.R.drawable.ic_dialog_alert)
.setTitle("Are you sure?")
.setMessage("Do you want to delete from favorites?")
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int which) {
try{
SQLiteDatabase favHymns = favContext.openOrCreateDatabase("Songs", MODE_PRIVATE, null);
favHymns.execSQL("DELETE FROM favorites where hymnNum = '"+hymn_no+"'");
Toast.makeText(favContext.getApplicationContext(), "hymn deleted ", Toast.LENGTH_LONG).show();
}catch(Exception e){
e.printStackTrace();
}
}
})
.setNegativeButton("No", null)
.show();
return true;
}
});
}
#Override
public int getItemCount() {
return favNumbers.size();
}
#Override
public long getItemId(int position){
return position;
}
#Override
public int getItemViewType(int position){
return position;
}
public class ViewHolder extends RecyclerView.ViewHolder {
public TextView textViewFavNum;
public TextView textViewFavTitle;
RelativeLayout favParentLayout;
public ViewHolder(View itemView) {
super(itemView);
textViewFavNum = (TextView) itemView.findViewById(R.id.textViewFavNum);
textViewFavTitle = (TextView) itemView.findViewById(R.id.textViewFavTitle);
favParentLayout = (RelativeLayout) itemView.findViewById(R.id.favParentLayout);
}
}
}
'''favourite fragment'''
import android.app.FragmentManager;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.AppCompatActivity;
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.TextView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.logging.Handler;
import static android.content.Context.MODE_PRIVATE;
/**
* A simple {#link Fragment} subclass.
*/
public class Favourites extends Fragment {
private RecyclerView recyclerView;
private RecyclerView.Adapter adapter;
private ArrayList<String> favSongNumbers = new ArrayList<>();
private ArrayList<String> favSongTitles = new ArrayList<>();
private TextView favMessage;
public Favourites() {
// Required empty public constructor
}
View view;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
if(view == null) {
view = inflater.inflate(R.layout.fragment_favourites, container, false);
favMessage = (TextView) view.findViewById(R.id.favMessage);
recyclerView = (RecyclerView) view.findViewById(R.id.favRecyclerView);
// adapter.setHasStableIds(true);
Toast.makeText(this.getActivity(), "Long press to delete hymns from favorites", Toast.LENGTH_LONG).show();
initFavSongs();
}
return view;
}
private void initFavSongs(){
try{
favMessage.setText("");
SQLiteDatabase favHymns = this.getActivity().openOrCreateDatabase("Songs", MODE_PRIVATE, null);
Cursor c = favHymns.rawQuery("SELECT hymnNum, hymnTitle FROM favorites", null);
int hymnNumIndex = c.getColumnIndex("hymnNum");
int hymnTitleIndex = c.getColumnIndex("hymnTitle");
if(c.moveToFirst()) {
while (c != null) {
favSongNumbers.add(Integer.toString(c.getInt(hymnNumIndex)) + ". ");
favSongTitles.add(" " + c.getString(hymnTitleIndex));
c.moveToNext();
}
}else{
favMessage.setText("Oops!No favorite songs added yet.");
}
}catch (Exception e){
e.printStackTrace();
}
initRecyclerView();
}
private void initRecyclerView(){
adapter = new FavouriteAdapter(this.getActivity(), favSongNumbers, favSongTitles);
recyclerView.setAdapter(adapter);
recyclerView.setLayoutManager(new LinearLayoutManager(this.getActivity()));
}
}

Pass a listener to the adapter and invoke it at the time of item delete from database. Then update your list and as well as your adapter.Like this way:
First create a listener:
public interface UpdateListener {
void onValueChangedListener();
}
Initialize the listener in Adapter class that comes from fragment.
private UpdateListener updateListener;
public FavouriteAdapter(Context favContext, ArrayList<String> favNumbers, ArrayList<String> favTitles,UpdateListener updateListener ) {
this.favContext = favContext;
this.favNumbers = favNumbers;
this.favTitles = favTitles;
this.updateListener=updateListener;
}
holder.favParentLayout.setOnLongClickListener(new View.OnLongClickListener() {
#Override
public boolean onLongClick(final View view) {
new AlertDialog.Builder(view.getContext())
.setIcon(android.R.drawable.ic_dialog_alert)
.setTitle("Are you sure?")
.setMessage("Do you want to delete from favorites?")
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int which) {
try{
SQLiteDatabase favHymns = favContext.openOrCreateDatabase("Songs", MODE_PRIVATE, null);
favHymns.execSQL("DELETE FROM favorites where hymnNum = '"+hymn_no+"'");
Toast.makeText(favContext.getApplicationContext(), "hymn deleted ", Toast.LENGTH_LONG).show();
// when any item delete from database notify the fragment through this
// listener for updating your adapter
updateListener.onValueChangedListener();
}catch(Exception e){
e.printStackTrace();
}
}
})
.setNegativeButton("No", null)
.show();
return true;
}
});
// this method is needed for updating your adapter
public void update(ArrayList<String> favNumbers, ArrayList<String> favTitles){
this.favNumbers = favNumbers;
this.favTitles = favTitles;
}
Implement the listener in your fragment and reinitialize your list.
public class Favourites extends Fragment implements UpdateListener {
private void initRecyclerView(){
// pass listener
adapter = new FavouriteAdapter(this.getActivity(), favSongNumbers, favSongTitles,this);
}
private void updateFavSongs(){
favSongNumbers.clear;
favSongTitles.clear;
try{
favMessage.setText("");
SQLiteDatabase favHymns = this.getActivity().openOrCreateDatabase("Songs", MODE_PRIVATE, null);
Cursor c = favHymns.rawQuery("SELECT hymnNum, hymnTitle FROM favorites", null);
int hymnNumIndex = c.getColumnIndex("hymnNum");
int hymnTitleIndex = c.getColumnIndex("hymnTitle");
if(c.moveToFirst()) {
while (c != null) {
favSongNumbers.add(Integer.toString(c.getInt(hymnNumIndex)) + ". ");
favSongTitles.add(" " + c.getString(hymnTitleIndex));
c.moveToNext();
}
}else{
favMessage.setText("Oops!No favorite songs added yet.");
}
}catch (Exception e){
e.printStackTrace();
}
adapter.update(favSongNumbers,favSongTitles);
adapter.notifyDataSetChanged()
}
#Override
public void onValueChangedListener(){
updateFavSongs();
}
}