Develop Reference

Notify adapter on item inserted in RoomDatabase and update the recyclerView

I am creating a notes app with java, i added room database to my app and when user saves a notes it adds it to database but doesn't shows in recyclerView immediately, when i reloads the app then it shows up, how and where should i insert notifyiteminserted so that recyclerView changes immediately
I have tried onResume Method but that results in app crash.
This is my MainActivity.
import android.annotation.SuppressLint;
import android.content.Intent;
import android.os.Bundle;
import android.widget.Button;
import android.widget.Toast;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import androidx.lifecycle.Observer;
import androidx.lifecycle.ViewModelProvider;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import androidx.recyclerview.widget.StaggeredGridLayoutManager;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity {
static ArrayList<Notes> arrNotes;
#SuppressLint("StaticFieldLeak")
RecyclerViewAdapter adapter;
RecyclerView.LayoutManager layoutManager;
notesModelView modelView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
DatabaseHelper dbHelper = DatabaseHelper.getDatabase(this);
arrNotes = (ArrayList<Notes>) dbHelper.notesDao().getAllNotes();
RecyclerView recyclerView = findViewById(R.id.recycler_view);
adapter = new RecyclerViewAdapter(this, arrNotes);
recyclerView.setAdapter(adapter);
//setting up recycler view
layoutManager = new StaggeredGridLayoutManager(2, LinearLayoutManager.VERTICAL);
recyclerView.setLayoutManager(layoutManager);
//Setting custom Toolbar
Toolbar toolbar1 = findViewById(R.id.toolbar);
setSupportActionBar(toolbar1);
//Moving from MainActivity to add_Notes Activity
Button button = findViewById(R.id.floatingActionButton);
button.setOnClickListener(view -> {
Intent intent = new Intent(MainActivity.this, addActivity.class);
startActivity(intent);
});
}
}
This is my add_Activity.
package com.example.keepnotes;
import android.os.Bundle;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import java.util.Objects;
public class addActivity extends AppCompatActivity {
MainActivity mainActivity;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add);
Toolbar toolbar_add = findViewById(R.id.toolbar_add_activity);
setSupportActionBar(toolbar_add);
Objects.requireNonNull(getSupportActionBar()).setDisplayHomeAsUpEnabled(true);
toolbar_add.setNavigationIcon(R.drawable.back_button);
toolbar_add.setNavigationOnClickListener(view -> onBackPressed());
EditText titleText = findViewById(R.id.add_activity_title);
EditText bodyText = findViewById(R.id.add_activity_text);
Button saveBtn = findViewById(R.id.button);
DatabaseHelper database = DatabaseHelper.getDatabase(this);
saveBtn.setOnClickListener(view -> {
String titleBody = titleText.getText().toString();
String textBody = bodyText.getText().toString();
if (titleBody.equals("") && textBody.equals("")) {
Toast.makeText(addActivity.this, "Fields can't be empty",
Toast.LENGTH_LONG).show();
} else {
database.notesDao().addNotes(new Notes(titleBody, textBody));
finish();
}
});
}
}
How can i notify adapter the changes on each item add in database.
Here is my MainActivity after update to liveData.
import android.annotation.SuppressLint;
import android.content.Intent;
import android.os.Bundle;
import android.widget.Button;
import android.widget.Toast;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import androidx.lifecycle.Observer;
import androidx.lifecycle.ViewModelProvider;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import androidx.recyclerview.widget.StaggeredGridLayoutManager;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity {
static ArrayList<Notes> arrNotes;
#SuppressLint("StaticFieldLeak")
RecyclerViewAdapter adapter;
RecyclerView.LayoutManager layoutManager;
notesModelView modelView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
DatabaseHelper dbHelper = DatabaseHelper.getDatabase(this);
modelView = new ViewModelProvider(this).get(notesModelView.class);
modelView.getAllNotes().observe(this, new Observer<List<Notes>>() {
#Override
public void onChanged(List<Notes> notes) {
arrNotes = (ArrayList<Notes>) notes;
}
});
arrNotes = (ArrayList<Notes>) dbHelper.notesDao().getAllNotes();
RecyclerView recyclerView = findViewById(R.id.recycler_view);
adapter = new RecyclerViewAdapter(this, arrNotes);
recyclerView.setAdapter(adapter);
//setting up recycler view
layoutManager = new StaggeredGridLayoutManager(2, LinearLayoutManager.VERTICAL);
recyclerView.setLayoutManager(layoutManager);
//Setting custom Toolbar
Toolbar toolbar1 = findViewById(R.id.toolbar);
setSupportActionBar(toolbar1);
//Moving from MainActivity to add_Notes Activity
Button button = findViewById(R.id.floatingActionButton);
button.setOnClickListener(view -> {
Intent intent = new Intent(MainActivity.this, addActivity.class);
startActivity(intent);
});
}
}
this is Dao.
import androidx.lifecycle.LiveData;
import androidx.room.Dao;
import androidx.room.Delete;
import androidx.room.Insert;
import androidx.room.Query;
import androidx.room.Update;
import java.util.List;
#Dao
public interface NotesDao {
#Query("SELECT * FROM notesTable")
List<Notes> getAllNotes();
#Query("SELECT * FROM notesTable")
LiveData<List<Notes>> findAllNotes();
#Insert
void addNotes(Notes note);
#Update
void updateNotes(Notes note);
#Delete
void deleteNotes(Notes note);
}
And here is my ViewModel
package com.example.keepnotes;
import android.app.Application;
import androidx.annotation.NonNull;
import androidx.lifecycle.AndroidViewModel;
import androidx.lifecycle.LiveData;
import java.util.List;
public class notesModelView extends AndroidViewModel {
DatabaseHelper databaseHelper;
public notesModelView(#NonNull Application application) {
super(application);
databaseHelper = DatabaseHelper.getDatabase(application.getApplicationContext());
}
public LiveData<List<Notes>> getAllNotes() {
return databaseHelper.notesDao().findAllNotes();
}
}
Here is my RecyclerView adapter
package com.example.keepnotes;
import android.annotation.SuppressLint;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.cardview.widget.CardView;
import androidx.recyclerview.widget.RecyclerView;
import java.util.ArrayList;
import java.util.List;
public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.ViewHolder> {
Context context;
ArrayList<Notes> arrNotes;
DatabaseHelper databaseHelper;
RecyclerViewAdapter(Context context, ArrayList<Notes> arrNotes, DatabaseHelper databaseHelper) {
this.context = context;
this.arrNotes = arrNotes;
this.databaseHelper = databaseHelper;
}
#NonNull
#Override
public ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(context).inflate(R.layout.single_view, parent, false);
return new ViewHolder(view);
}
#Override
public void onBindViewHolder(#NonNull ViewHolder holder, #SuppressLint("RecyclerView") int position) {
holder.title.setText(arrNotes.get(position).title);
holder.body.setText(arrNotes.get(position).text);
holder.index.setText(String.valueOf(position + 1));
holder.llView.setOnLongClickListener(new View.OnLongClickListener() {
#Override
public boolean onLongClick(View view) {
AlertDialog.Builder alert = new AlertDialog.Builder(context)
.setTitle("Delete view")
.setMessage("Are you sure to delete")
.setIcon(R.drawable.ic_baseline_delete_24)
.setPositiveButton("yes", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
databaseHelper.notesDao().deleteNotes(new Notes(arrNotes.get(position).id,arrNotes.get(position).title,arrNotes.get(position).text));
notifyItemRemoved(position);
notifyItemRangeChanged(position, arrNotes.size());
}
})
.setNegativeButton("No", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
}
});
alert.show();
return true;
}
});
}
#Override
public int getItemCount() {
return arrNotes.size();
}
public class ViewHolder extends RecyclerView.ViewHolder {
TextView title, body, index;
CardView llView;
public ViewHolder(View itemView) {
super(itemView);
title = itemView.findViewById(R.id.text_title_view);
body = itemView.findViewById(R.id.text_text_view);
index = itemView.findViewById(R.id.index);
llView = itemView.findViewById(R.id.card_View);
databaseHelper = DatabaseHelper.getDatabase(context);
}
}
}
It deletes the selected notes but also crashes immediately after confirming delete.
and it throws following error
java.lang.IndexOutOfBoundsException: Inconsistency detected. Invalid view holder adapter positionViewHolder{535e3b3 position=5 id=-1, oldPos=4, pLpos:4 scrap [attachedScrap] tmpDetached not recyclable(1) no parent} androidx.recyclerview.widget.RecyclerView{11f4816 VFED..... ......ID 31,171-689,1048 #7f090165 app:id/recycler_view}, adapter:com.example.keepnotes.RecyclerViewAdapter#fd652a0, layout:androidx.recyclerview.widget.StaggeredGridLayoutManager#32e1e59, context:com.example.keepnotes.MainActivity#286bccd

Remove this two line
notifyItemRemoved(position);
notifyItemRangeChanged(position, arrNotes.size());
OLD ANSWER
First, if you use liveData you don't need to call the method
arrNotes = (ArrayList<Notes>) dbHelper.notesDao().getAllNotes();
just keep a reference to the adapter instance and whenever there is a change from liveData call the notifyDataSetChanged method.
adapter = new RecyclerViewAdapter(this,new List<Notes>());
RecyclerView recyclerView = findViewById(R.id.recycler_view);
recyclerView.setAdapter(adapter);
modelView.getAllNotes().observe(this, new Observer<List<Notes>>() {
#Override
public void onChanged(List<Notes> notes) {
arrNotes.clear();
arrNotes.addAll(notes);
adapter.notifyDataSetChanged()
}
});

observe a LiveData object as it is not a LifecycleOwner
Use observeForever() on the LiveData, manually unregistering via removeObserver() when appropriate (onDestroy() of the service, if not sooner).
Bear in mind that standard service limitations apply here (e.g., services run for ~1 minute on Android 8.0+ unless they are foreground services), so it may be that you need to consider other approaches anyway. 🤞
Also you can read more in original post in here -> Link

Problem with fragment communication(Attempt to invoke virtual method)

I have a tabbed activity with 2 fragments. I'm trying to transmit a string from the first fragment to the second fragment but I'm getting NULL POINTER EXCEPTION.
Here is the MainActivity.java:
package com.example.myapplication;
import android.os.Bundle;
import com.google.android.material.tabs.TabLayout;
import androidx.fragment.app.FragmentTransaction;
import androidx.viewpager.widget.ViewPager;
import androidx.appcompat.app.AppCompatActivity;
import com.example.myapplication.ui.main.SectionsPagerAdapter;
public class MainActivity extends AppCompatActivity implements Frag1.Exchange {
private static final String TAG = "MainActivity";
private SectionsPagerAdapter sectionsPagerAdapter;
private ViewPager viewPager;
private TabLayout tabLayout;
private void setupViewPager(ViewPager viewPager){
SectionsPagerAdapter sectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
sectionsPagerAdapter.addFragment(new Frag1(), "FirstTab");
sectionsPagerAdapter.addFragment(new Frag2(), "SecondTab");
viewPager.setAdapter(sectionsPagerAdapter);
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
sectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
viewPager = (ViewPager) findViewById(R.id.view_pager);
setupViewPager(viewPager);
tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
}
#Override
public void stringExchange(String s) {
Frag2 frag2 = (Frag2) getSupportFragmentManager().findFragmentByTag("SecondTab");
frag2.displayExchange(s);
}
}
Here is SectionsPagerAdapter.java
package com.example.myapplication.ui.main;
import android.content.Context;
import androidx.annotation.Nullable;
import androidx.annotation.StringRes;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentPagerAdapter;
import com.example.myapplication.R;
import java.util.ArrayList;
import java.util.List;
/**
* A [FragmentPagerAdapter] that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class SectionsPagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> fragmentList = new ArrayList<>();
private final List<String> stringList = new ArrayList<>();
public void addFragment(Fragment fragment, String title){
fragmentList.add(fragment);
stringList.add(title);
}
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
// getItem is called to instantiate the fragment for the given page.
// Return a (defined as a static inner class below).
return fragmentList.get(position);
}
#Nullable
#Override
public CharSequence getPageTitle(int position) {
return stringList.get(position);
}
#Override
public int getCount() {
// Show 2 total pages.
return fragmentList.size();
}
}
Here is Frag1.java:
package com.example.myapplication;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.os.Build;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.webkit.WebView;
import android.widget.Button;
import android.widget.SeekBar;
import android.widget.TextView;
import android.widget.Toast;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentTransaction;
public class Frag1 extends Fragment{
private static final String TAG = "FirstTab";
private Button transfer;
private Exchange ex;
public interface Exchange{
public void stringExchange(String s);
}
#Nullable
#Override
public View onCreateView(#NonNull final LayoutInflater inflater, #Nullable final ViewGroup container, #Nullable Bundle savedInstanceState) {
final View view = inflater.inflate(R.layout.tab1_fragment, container, false);
transfer = (Button) view.findViewById(R.id.button2);
ex = (Exchange) getActivity();
transfer.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String s = "Test";
ex.stringExchange(s);
}
});
return view;
}
}
With its xlm tab1_fragment.xlm:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="16dp"
android:id="#+id/tab1"
>
<Button
android:id="#+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/transfer"
android:layout_centerInParent="true"/>
</RelativeLayout>
And finally here is the Frag2.java:
package com.example.myapplication;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import java.util.ArrayList;
public class Frag2 extends Fragment {
private static final String TAG = "SecondTab";
private ListView listView;
private ArrayList<String> arrayList = new ArrayList<>();
#Nullable
#Override
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.tab2_fragment, container, false);
listView = (ListView) view.findViewById(R.id.list_view);
ArrayAdapter arrayAdapter = new ArrayAdapter(getContext(),android.R.layout.simple_list_item_1,arrayList);
listView.setAdapter(arrayAdapter);
return view;
}
public void displayExchange(String s){
arrayList.add(s);
}
}
I think the problem is in MainActivity when I call findFragmentByTag("SecondTab") because it's tag is not set to SecondTab but i don't know how to set it.
Any help will be apreciated!

Use ViewModel to share data between fragments. Refer: https://developer.android.com/topic/libraries/architecture/viewmodel.html#sharing

store multiple views in recylerview using sharedpreferences on runtime

Hi am using a "Add" button in ActionBar of my app on clicking it a ListView gets open and the user can tap on any list item to add that item to the RecyclerView which is the parent activity(MainActivity holding the Recyclerview) but on exiting the app the last added item stays on MainActivity's view. I guess SharedPreferences' Editor is getting overwritten everytime. Can you please help in providing some snippet as i can't call editor.put() method multiple times as the click happens on listView. My RecyclerView contains an image and a text.
Here is my MainActivity's Code
package com.example.mohitmehndiratta.customlistadap;
import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageManager;
import android.graphics.drawable.Icon;
import android.support.v7.app.ActionBar;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.List;
import static android.support.v7.widget.LinearLayoutManager.*;
public class MainActivity extends AppCompatActivity {
public static ArrayList<DataSet> alist;
int i;
RecyclerView rv;
static RecycledAdap adap;
static String args;
static int rid;
static SharedPreferences sharedPreferences;
public static void addnow(String arg)
{
args=arg;
rid=R.drawable.i;
alist.add(new DataSet(args,rid));
adap.notifyDataSetChanged();
SharedPreferences.Editor editor=sharedPreferences.edit();
editor.putInt("Iconid",rid);
editor.putString("AppName",args);
editor.apply();
if (sharedPreferences!=null)
{
int x=sharedPreferences.getInt("Iconid",rid);
String y=sharedPreferences.getString("AppName",args);
addnow(y);
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater=getMenuInflater();
inflater.inflate(R.menu.new_menu,menu);
return super.onCreateOptionsMenu(menu);
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
if(item.getItemId()==R.id.addbtn)
{
Intent intent=new Intent(this,AppList.class);
startActivity(intent);
}
return super.onOptionsItemSelected(item);
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
sharedPreferences = getSharedPreferences("MyPrefs",getApplicationContext().MODE_PRIVATE);
rv=(RecyclerView)findViewById(R.id.rv);
RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(getApplicationContext());
rv.setLayoutManager(mLayoutManager);
rv.setItemAnimator(new DefaultItemAnimator());
rv.addItemDecoration(new ItemDecoration(this, LinearLayoutManager.VERTICAL));
for(i=0;i<DataModel.name.length;i++) {
alist = new ArrayList<DataSet>();
alist.add(new DataSet("Paytm",R.drawable.i));
alist.add(new DataSet("Facebook",R.drawable.i1));
alist.add(new DataSet("ShareIt",R.drawable.i2));
alist.add(new DataSet("Instagram",R.drawable.i3));
alist.add(new DataSet("BookMyShow",R.drawable.i4));
}
adap=new RecycledAdap(getApplicationContext(),alist);
rv.setAdapter(adap);
MyListener mlistener=new MyListener(getApplicationContext(),rv, new MyListener.ReClickListener() {
#Override
public void onClick(int position) {
Toast.makeText(getApplicationContext(),"Launching item"+position,Toast.LENGTH_SHORT).show();
LauncherHandler lh=new LauncherHandler(position);
String pkname=lh.getpack();
AppDialog adialog=new AppDialog();
adialog.packagenameset(pkname);
adialog.show(getFragmentManager(),"AppDialogFrag");
}
#Override
public void onLongClick(int position) {
LauncherHandler lh=new LauncherHandler(position);
String pkname=lh.getpack();
Toast.makeText(getApplicationContext(),"Launching item"+position,Toast.LENGTH_SHORT).show();
AppDialog adialog=new AppDialog();
adialog.packagenameset(pkname);
adialog.show(getFragmentManager(),"AppDialogFrag");
}
});
rv.addOnItemTouchListener(mlistener);
if (sharedPreferences!=null)
{
int x=sharedPreferences.getInt("Iconid",rid);
String y=sharedPreferences.getString("AppName",args);
addnow(y);
}
else
{
Toast.makeText(getApplication(),"There is nothing in app's cache",Toast.LENGTH_SHORT).show();
}
}
}
ListView code :
package com.example.mohitmehndiratta.customlistadap;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageManager;
import android.graphics.drawable.Drawable;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.List;
public class AppList extends AppCompatActivity {
ListView lv;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_app_list);
PackageManager pm=getPackageManager();
ArrayList<ApplicationInfo> li= (ArrayList<ApplicationInfo>) pm.getInstalledApplications(0);
ArrayList al=new ArrayList<String>();
String str;
String strpk;
ApplicationInfo info;
for(int i=0;i<li.size();i++)
{
info=li.get(i);
str=info.loadLabel(pm).toString();
Drawable appicon=info.loadIcon(pm);
al.add(str);
}
lv=(ListView)findViewById(R.id.listView);
final ArrayAdapter adap=new ArrayAdapter<String>(this,R.layout.support_simple_spinner_dropdown_item,al);
lv.setAdapter(adap);
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
String text=lv.getItemAtPosition(i).toString();
Toast.makeText(getApplicationContext(),text+i,Toast.LENGTH_SHORT).show();
MainActivity.addnow(text);
}
});
}
}

Data not being displayed when switching between tabs

I am using the https://github.com/astuetz/PagerSlidingTabStrip/ library. My activity consists of 3 "tabs" and each of these tabs has it's own fragment.
The problem is that whenever I load tab 3, all the data in tab 1 is lost and will not be refreshed.
All 3 fragments are filled with a listview and have similar code.
I can't figure out why it keeps happening, but it seems as if whenever I load a tab that is not the direct "neighbour" of the currently selected tab, the currently selected tab gets unloaded.
Basically, I have 3 tabs. If I load tab 3, tab 1 unloads and doesn't reload. Tab 2 always remains filled (I assume because tab 2 is always either a] the neighbour of tab 1 or b] the neighbour of tab 3).
OrdersActivity.java
package nl.*.android.order;
import android.content.Intent;
import android.support.v4.app.Fragment;
import android.support.v4.view.ViewPager;
import com.astuetz.PagerSlidingTabStrip;
import org.androidannotations.annotations.AfterViews;
import org.androidannotations.annotations.EActivity;
import org.androidannotations.annotations.ViewById;
import nl.*.android.DrawerActivity;
import nl.*.android.home.HomeActivity_;
import nl.*.android.R;
import nl.*.android.utility.IFragmentSetter;
import nl.*.android.utility.TabsPagerAdapter;
#EActivity(R.layout.activity_orders)
public class OrdersActivity extends DrawerActivity implements IFragmentSetter {
#ViewById
public ViewPager viewpager;
#ViewById
public PagerSlidingTabStrip strip;
private TabsPagerAdapter adapter;
#AfterViews
public void init() {
buildDrawer();
adapter = new TabsPagerAdapter(getSupportFragmentManager(), this);
addFragments();
viewpager.setAdapter(adapter);
strip.setViewPager(viewpager);
if (getSupportActionBar() != null) {
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setTitle("Bestellingen");
getSupportActionBar().setHomeAsUpIndicator(R.drawable.ic_menu_white);
}
}
private void addFragments() {
adapter.addFragment(new OrdersNewFragment_(), "Nieuw");
adapter.addFragment(new OrdersDeliveryFragment_(), "Afleveren");
adapter.addFragment(new OrdersPickupFragment_(), "Ophalen");
}
#Override
public void setFragment(Fragment fragment) {
//geen implementatie nodig
}
#Override
public void onBackPressed() {
super.onBackPressed();
final Intent i = HomeActivity_.intent(getApplicationContext()).get();
i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(i);
finish();
}
}
OrdersNewFragment.java [Tab 1]
package nl.*.android.order;
import android.support.v4.app.Fragment;
import android.widget.ListView;
import org.androidannotations.annotations.AfterViews;
import org.androidannotations.annotations.Background;
import org.androidannotations.annotations.Bean;
import org.androidannotations.annotations.EFragment;
import org.androidannotations.annotations.UiThread;
import org.androidannotations.annotations.ViewById;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import nl.*.android.R;
import nl.*.android.backend.API;
import nl.*.android.backend.APIFactory;
import nl.*.android.model.MOrderItem;
import nl.*.android.model.MOrders;
#EFragment(R.layout.fragment_orders_overview)
public class OrdersNewFragment extends Fragment {
#Bean
public APIFactory apiFactory;
private API api;
private List<MOrderItem> items = new ArrayList<>();
private OrderListAdapter adapter;
#ViewById
public ListView ordersList;
#AfterViews
public void init() {
api = apiFactory.get();
getNewOrders();
adapter = new OrderListAdapter(getActivity(), R.id.ordersList, items);
ordersList.setAdapter(adapter);
dataChanged();
}
#UiThread
public void dataChanged() {
adapter.notifyDataSetChanged();
}
#Background
public void getNewOrders() {
items.clear();
final MOrders result = api.getOrdersForNew();
if (result != null) {
Collections.addAll(items, result.result.orderList);
}
}
}
OrdersDeliveryFragment.java [Tab 2]
package nl.*.android.order;
import android.support.v4.app.Fragment;
import android.widget.ListView;
import org.androidannotations.annotations.AfterViews;
import org.androidannotations.annotations.Background;
import org.androidannotations.annotations.Bean;
import org.androidannotations.annotations.EFragment;
import org.androidannotations.annotations.UiThread;
import org.androidannotations.annotations.ViewById;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import nl.*.android.R;
import nl.*.android.backend.API;
import nl.*.android.backend.APIFactory;
import nl.*.android.model.MOrderItem;
import nl.*.android.model.MOrders;
#EFragment(R.layout.fragment_orders_delivery)
public class OrdersDeliveryFragment extends Fragment {
#Bean
public APIFactory apiFactory;
private API api;
private List<MOrderItem> items = new ArrayList<>();
private OrderListAdapter adapter;
#ViewById
public ListView ordersList;
#AfterViews
public void init() {
api = apiFactory.get();
getDeliveryOrders();
adapter = new OrderListAdapter(getActivity(), R.id.ordersList, items);
ordersList.setAdapter(adapter);
dataChanged();
}
#UiThread
public void dataChanged() {
adapter.notifyDataSetChanged();
}
#Background
public void getDeliveryOrders() {
items.clear();
final MOrders result = api.getOrdersForDelivery();
if (result != null) {
Collections.addAll(items, result.result.orderList);
}
}
}
OrdersPickupFragment.java [Tab 3]
package nl.*.android.order;
import android.support.v4.app.Fragment;
import android.widget.ListView;
import org.androidannotations.annotations.AfterViews;
import org.androidannotations.annotations.Background;
import org.androidannotations.annotations.Bean;
import org.androidannotations.annotations.EFragment;
import org.androidannotations.annotations.UiThread;
import org.androidannotations.annotations.ViewById;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import nl.*.android.R;
import nl.*.android.backend.API;
import nl.*.android.backend.APIFactory;
import nl.*.android.model.MOrderItem;
import nl.*.android.model.MOrders;
#EFragment(R.layout.fragment_orders_pickup)
public class OrdersPickupFragment extends Fragment {
#Bean
public APIFactory apiFactory;
private API api;
private List<MOrderItem> items = new ArrayList<>();
private OrderListAdapter adapter;
#ViewById
public ListView ordersList;
#AfterViews
public void init() {
api = apiFactory.get();
getPickupOrders();
adapter = new OrderListAdapter(getActivity(), R.id.ordersList, items);
ordersList.setAdapter(adapter);
dataChanged();
}
#UiThread
public void dataChanged() {
adapter.notifyDataSetChanged();
}
#Background
public void getPickupOrders() {
items.clear();
final MOrders result = api.getOrdersForPickup();
if (result != null) {
Collections.addAll(items, result.result.orderList);
}
}
}
OrderListAdapter.java
package nl.****.android.order;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.List;
import java.util.Locale;
import nl.*.android.R;
import nl.*.android.model.MOrderItem;
/**
* #author Niels
* #version 1.0
* #since 4-9-2015
*/
public class OrderListAdapter extends ArrayAdapter<MOrderItem> {
private List<MOrderItem> itemList = new ArrayList<>();
private Context context;
private OrdersActivity activity;
private static final SimpleDateFormat FORMATTER = new SimpleDateFormat("dd-MM-yyyy HH:mm", Locale.FRENCH);
public OrderListAdapter(Context context, int resource, List<MOrderItem> orderList) {
super(context, resource, orderList);
this.itemList = orderList;
this.context = context;
}
#Override
public View getView(final int position, View view, ViewGroup parent) {
view = LayoutInflater.from(getContext()).inflate(R.layout.list_single, parent, false);
MOrderItem item = itemList.get(position);
TextView label = (TextView) view.findViewById(R.id.txtKlant);
TextView txt = (TextView) view.findViewById(R.id.txtDate);
label.setText(item.name);
txt.setText(FORMATTER.format(item.placeDate));
return view;
}
}
Thanks for any and all help.

Turns out I was notifying my listview that it's data set had changed before I actually finished getting the results.
Solution: move the line "dataChanged()" in the #AfterViews annotated method #init() to the #Background annotated method #getOrders().

ActionBarSherlock and FragmentTabsPager

As a lot of people have been doing so far, I'm implementing the FragmentTabsPager into my app, which is using ActionBarSherlock 4.0. However, I'm lost.
Fragments, and all of Google's little ideas, plans and methods surrounding it, are confusing me. If anyone could take a look at my code and walk me through this, providing help in making it work, I would thank them a thousand times :D.
I have another project with a sort-of beginning for a ViewPager, but the Tabs just mix better, especially with them being in the ActionBar on landscape and tablets.
My code is all zipped up and ready to go over here:
http://dl.dropbox.com/u/21807195/Antonius%20College%202.zip
Thanks in advance!

I will show you my code that has a ViewPager, TabListener, and system of Fragments linked to each tab. It implements ABS, but as of yet, still crashes on Gingerbread and lower (works beautifully on ICS, though):
import java.util.ArrayList;
import library.DatabaseHandler;
import org.json.JSONObject;
import com.actionbarsherlock.R;
import com.actionbarsherlock.app.ActionBar;
import com.actionbarsherlock.app.ActionBar.Tab;
import com.actionbarsherlock.app.SherlockFragmentActivity;
import android.app.AlertDialog;
import android.app.Dialog;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.MenuItem.OnMenuItemClickListener;
import android.view.View.OnClickListener;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Switch;
import android.widget.TextView;
import android.widget.Toast;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
public class Polling extends SherlockFragmentActivity {
private ViewPager mViewPager;
private TabsAdapter mTabsAdapter;
private final static String TAG = "21st Polling:";
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mViewPager = new ViewPager(this);
mViewPager.setId(R.id.pager);
setContentView(mViewPager);
ActionBar bar = getSupportActionBar();
bar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
bar.setDisplayShowTitleEnabled(false);
bar.setDisplayShowHomeEnabled(false);
mTabsAdapter = new TabsAdapter(this, mViewPager);
mTabsAdapter.addTab(bar.newTab().setText(R.string.login),
LoginFragment.class, null);
mTabsAdapter.addTab(bar.newTab().setText(R.string.economics),
EconFragment.class, null);
mTabsAdapter.addTab(bar.newTab().setText(R.string.elections),
ElectionsFragment.class, null);
mTabsAdapter.addTab(bar.newTab().setText(R.string.politics),
PoliticsFragment.class, null);
mTabsAdapter.addTab(bar.newTab().setText(R.string.science),
ScienceFragment.class, null);
mTabsAdapter.addTab(bar.newTab().setText(R.string.finance),
FinanceFragment.class, null);
mTabsAdapter.addTab(bar.newTab().setText(R.string.religion),
ReligionFragment.class, null);
mTabsAdapter.addTab(bar.newTab().setText(R.string.military),
MilitaryFragment.class, null);
mTabsAdapter.addTab(bar.newTab().setText(R.string.international),
InternationalFragment.class, null);
Log.v(TAG, (String)bar.getTabAt(0).getText());
}
public static class TabsAdapter extends FragmentPagerAdapter
implements ActionBar.TabListener, ViewPager.OnPageChangeListener {
private final Context mContext;
private final ActionBar mActionBar;
private final ViewPager mViewPager;
private final ArrayList<TabInfo> mTabs = new ArrayList<TabInfo>();
static final class TabInfo {
private final Class<?> clss;
private final Bundle args;
TabInfo(Class<?> _class, Bundle _args) {
clss = _class;
args = _args;
}
}
public TabsAdapter(SherlockFragmentActivity activity, ViewPager pager) {
super(activity.getSupportFragmentManager());
mContext = activity;
mActionBar = activity.getSupportActionBar();
mViewPager = pager;
mViewPager.setAdapter(this);
mViewPager.setOnPageChangeListener(this);
}
public void addTab(ActionBar.Tab tab, Class<?> clss, Bundle args) {
TabInfo info = new TabInfo(clss, args);
tab.setTag(info);
tab.setTabListener(this);
mTabs.add(info);
mActionBar.addTab(tab);
notifyDataSetChanged();
}
public int getCount() {
return mTabs.size();
}
public SherlockFragment getItem(int position) {
TabInfo info = mTabs.get(position);
return (SherlockFragment)Fragment.instantiate(mContext, info.clss.getName(), info.args);
}
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
public void onPageSelected(int position) {
mActionBar.setSelectedNavigationItem(position);
}
public void onPageScrollStateChanged(int state) {
}
public void onTabSelected(Tab tab, FragmentTransaction ft) {
mViewPager.setCurrentItem(tab.getPosition());
//Log.v(TAG, "clicked");
Object tag = tab.getTag();
for (int i=0; i<mTabs.size(); i++) {
if (mTabs.get(i) == tag) {
mViewPager.setCurrentItem(i);
}
}
}
public void onTabUnselected(Tab tab, FragmentTransaction ft) {}
public void onTabReselected(Tab tab, FragmentTransaction ft) {}
public void onTabReselected(Tab tab, android.app.FragmentTransaction ft) {}
public void onTabUnselected(Tab tab, android.app.FragmentTransaction ft) {}
}
And here is what one fragment looks like:
package com.davekelley.polling;
import com.actionbarsherlock.R;
import com.actionbarsherlock.app.SherlockFragment;
import android.support.v4.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class MilitaryFragment extends SherlockFragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.militaryfragment, container, false);
}
}
My last note would that my code still has one other issue: individual fragments do not always reload their interface after the user press back (which results in removing the entire app from the screen, regardless which tab/fragment they are on, because I have no backStack). So that's what I'm working through now. I think once I have that sorted, I'll try to figure out why I still don't have Gingerbread execution functioning properly. Either way, I hope looking through this code helps you out.
Here is a fragment with some onClickListeners:
import com.actionbarsherlock.R;
import com.actionbarsherlock.app.SherlockFragment;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Context;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TableLayout;
import android.widget.TableRow;
import android.widget.TextView;
import android.widget.Toast;
public class LoginFragment extends SherlockFragment {
Button loginButton;
Button registerButton;
Polling activity;
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.loginfragment, container, false);
return v;
}
public void onResume() {
super.onResume();
Log.d("Econ", "onresume");
loginButton = (Button) getActivity().findViewById(R.id.loginButton);
loginButton.setOnClickListener(loginListener);
registerButton = (Button) getActivity().findViewById(R.id.registerButton);
registerButton.setOnClickListener(registerListener);
}
public OnClickListener loginListener = new OnClickListener() {
#Override
public void onClick(View v) {
if(loginButton.getText().toString() == "Log Out") {
activity.loginReport(2);
loginButton.setText(R.string.login);
//Remove user from dB sqllite when I know how
}
else {
Log.v("LoginF", "onclick");
ProgressDialog progressDialog = new ProgressDialog(getActivity());
progressDialog.setMessage("Logging in...");
LoginTask loginTask = new LoginTask((Polling) getActivity(), progressDialog);
loginTask.execute();
}
}
};
public OnClickListener registerListener = new OnClickListener() {
#Override
public void onClick(View v) {
Log.v("Register", "onclick");
ProgressDialog progressDialog = new ProgressDialog(getActivity());
progressDialog.setMessage("Registering new user...");
RegisterTask registerTask = new RegisterTask((Polling) getActivity(), progressDialog);
registerTask.execute();
}
};
public void onAttach(Activity activity) {
super.onAttach(activity);
this.activity = (Polling) activity;
}
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
}
public void onStart() {
super.onStart();
Log.d("Econ", "onstart");
}
public void onPause() {
super.onPause();Log.d("Econ", "onpause");
}
public void onStop() {
super.onStop();
Log.d("Econ", "onstop");
}
public void onDestroyView() {
super.onDestroyView();
Log.d("Econ", "ondestroyview");
}
public void onDestroy() {
super.onDestroy();
Log.d("Econ", "ondestroy");
}
public void onDetach() {
super.onDetach();
Log.d("Econ", "ondetach");
}
}
The loginTask objects that you see are actually classes that extend ASyncTask - they handle connecting to my server and registering/logging in.
I thought it would be helpful to add in one bit more of code. This is another one of my fragments, like LoginFragment, but it inflates a UI a little differently. Eventually, what you see in the while loop below, will head into an ASyncTask to acquire each question from the server, rather than the dummy string array you see:
public class EconFragment extends SherlockFragment {
private TableLayout questionContainer;
int pos = 0;
private String[] titles = {"The first title ", "hallo1","hallo2", "hallo3",
"hallo4", "hallo5","hallo6", "hallo7","hallo8", "hallo9"};
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
Log.v("Econ", "onCreateView");
View v = inflater.inflate(R.layout.econfragment, container, false);
questionContainer = (TableLayout) v.findViewById(R.id.questionContainer);
//bs
int leftMargin=5;
int topMargin=5;
int rightMargin=5;
int bottomMargin=5;
while (pos < 10) {
View question = inflater.inflate(R.layout.question, null);
question.setId(pos);
TextView title = (TextView) question.findViewById(R.id.questionTextView);
title.setText(titles[pos]);
Button charts = (Button) question.findViewById(R.id.chartsButton);
charts.setId(pos);
charts.setOnClickListener(chartsListener);
TableRow tr = (TableRow) question;
TableLayout.LayoutParams trParams = new TableLayout.LayoutParams(
TableLayout.LayoutParams.MATCH_PARENT,
TableLayout.LayoutParams.WRAP_CONTENT);
trParams.setMargins(leftMargin, topMargin, rightMargin, bottomMargin);
tr.setLayoutParams(trParams);
Log.v("econ", "while loop");
questionContainer.addView(tr);
pos++;
}
pos = 0;
return v;
}

I have ported the FragmentTabsPager Activity and associated Fragments from "Support4Demos" (Android Support library sample) to use ActionBarSherlock and true ActionBar Tabs. The sample includes an Activity that uses both a ViewPager and Tabs to switch between Fragments. The Fragments contain three kinds of ListViews. I've tested it from ICS down to Eclair (2.1). You can browse or download the code at http://code.google.com/p/sherlock-demo/.