The recyclerview in the fragment doesn't update no matter what I do
It's been a week now and I'm desperate for a solution as I need to present an update to clients within the week. So I have a recyclerview in a fragment that is populated with data fetched from a web service using volley library. If new data is added to the database, I want the recyclerview to reload/update to implement the changes or newly added changes. Now, I've tried many ways but failed to achieve what I need. I have tried the following:
-notifyDataSetChanged() in a handler on my adapter, inside onclick
-adapter.notifyItemRangeChanged（0，adapter.getItemCount（））;
- recyclerView.invalidate() in handler - detach and attach current fragment
- Tried the following code as well. Well, it works because it refreshes the whole activity and goes back to the initial fragment (i.e. the first page)
Intent intent = getActivity().getIntent();
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_NEW_TASK
| Intent.FLAG_ACTIVITY_NO_ANIMATION);
getActivity().overridePendingTransition(0, 0);
getActivity().finish();
getActivity().overridePendingTransition(0, 0);
startActivity(intent);
Fragment class
public class AddPlaylist extends Fragment {
RecyclerView recyclerView;
RecyclerAdapter adapter;
String[] id,title;
ArrayList<String> artist;
TextView text;
CreatePlaylist createPlaylist;
private CoordinatorLayout coordinatorLayout;
private FloatingActionButton fab;
View view;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
view = inflater.inflate(R.layout.addplaylist, container, false);
coordinatorLayout = (CoordinatorLayout) view.findViewById(R.id
.coordinatorLayout);
fab = (FloatingActionButton) view.findViewById(R.id.fab);
text = (TextView) view.findViewById(R.id.text);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
showInputDialog();
}
});
id = getArguments().getStringArray("id");
title = getArguments().getStringArray("title");
artist = new ArrayList<String>(Arrays.asList(title));
recyclerView= (RecyclerView) view.findViewById(R.id.my_recycler_view);
adapter = new RecyclerAdapter("addplaylist", id, artist, getActivity());
recyclerView.setAdapter(adapter);
recyclerView.invalidate();
recyclerView.setHasFixedSize(true);
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
adapter.notifyItemRangeChanged(0, adapter.getItemCount());
final Handler mHandler = new Handler();
mHandler.post(new Runnable() {
@Override
public void run() {
adapter.notifyDataSetChanged();
adapter.notifyItemRangeChanged(0, adapter.getItemCount());
recyclerView.invalidate();
Fragment frg = null;
frg = getFragmentManager().findFragmentByTag("playlist");
Bundle bundle = new Bundle();
AddPlaylist addPlaylist = new AddPlaylist();
bundle.putStringArray("id", JsonArray.ids);
bundle.putStringArray("title", JsonArray.titles);
addPlaylist.setArguments(bundle);
final FragmentTransaction ft = getFragmentManager().beginTransaction();
ft.detach(addPlaylist);
ft.attach(addPlaylist);
ft.commit();
}
});
return view;
}
protected void showInputDialog() {
// get prompts.xml view
LayoutInflater layoutInflater = LayoutInflater.from(getActivity());
View promptView = layoutInflater.inflate(R.layout.input_dialog, null);
AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(getActivity());
alertDialogBuilder.setView(promptView);
final EditText editText = (EditText) promptView.findViewById(R.id.edittext);
// setup a dialog window
alertDialogBuilder.setCancelable(false)
.setPositiveButton("OK", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
//text.setText("Hello, " + editText.getText());
createPlaylist.createPlaylist(editText.getText().toString());
/*Intent intent = getActivity().getIntent();
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_NEW_TASK
| Intent.FLAG_ACTIVITY_NO_ANIMATION);
getActivity().overridePendingTransition(0, 0);
getActivity().finish();
getActivity().overridePendingTransition(0, 0);
startActivity(intent);*/
/*Bundle bundle = new Bundle();
Collections collections = new Collections();
AddPlaylist addPlaylist = new AddPlaylist();
bundle.putStringArray("id", JsonArray.ids);
bundle.putStringArray("title", JsonArray.titles);
bundle.putString("fragment", "addfragment");
addPlaylist.setArguments(bundle);
Fragment frg = null;
frg = getFragmentManager().findFragmentByTag("playlist");
final FragmentTransaction ft = getFragmentManager().beginTransaction();
ft.detach(collections);
ft.attach(frg);
ft.commit();*/
/*getActivity().runOnUiThread(new Runnable() {
@Override
public void run() {
adapter.notifyDataSetChanged();
}
});*/
/*FragmentManager fragmentTransaction = getFragmentManager();
android.app.FragmentTransaction transaction = fragmentTransaction.beginTransaction();
Bundle bundle = new Bundle();
AddPlaylist addPlaylist = new AddPlaylist();
bundle.putStringArray("id", JsonArray.ids);
bundle.putStringArray("title", JsonArray.titles);
addPlaylist.setArguments(bundle);
transaction.addToBackStack("xyz");
transaction.add(R.id.containerView, addPlaylist);
//transaction.setTransition(FragmentTransaction.TRANSIT_ENTER_MASK);
transaction.commit();*/
adapter.notifyItemRangeChanged(0, adapter.getItemCount());
}
})
.setNegativeButton("Cancel",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
dialog.cancel();
}
});
// create an alert dialog
AlertDialog alert = alertDialogBuilder.create();
alert.show();
}
@UiThread
protected void dataSetChanged() {
adapter.notifyDataSetChanged();
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
id = getArguments().getStringArray("id");
title = getArguments().getStringArray("title");
artist = new ArrayList<String>(Arrays.asList(title));
adapter = new RecyclerAdapter("addplaylist", id, artist, getActivity());
adapter.notifyDataSetChanged();
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try{
createPlaylist = (CreatePlaylist) activity;
}catch(Exception e) {
}
}
public interface CreatePlaylist{
void createPlaylist(String name);
}
}
Sorry for the messy code. This is what all of me have tried.
This happens because your adapter is "lost". First, create the adapter. That's fine. Then you will get new data. What you do is create another adapter and change the data in the second adapter which is not attached to the RecyclerView.
It's not the most elegant solution, but it works. Change the following lines onActivityResult:
artist = new ArrayList<String>(Arrays.asList(title));
adapter = new RecyclerAdapter("addplaylist", id, artist, getActivity());
to
List<String> newArtist = new ArrayList<String>(Arrays.asList(title));
artist.clear();
artist.addAll(newArtist);
adapter.notifyDataSetChanged();
Since the list artistis an object, when you pass it to the Recycler adapter, you are updating the same instance, the same list, so there is no need to create a new adapter as the adapter still has access to the same instance. Think of it like a bucket of water. You can empty the bucket or fill it, but the bucket remains the same.