We Keep Coding

Android update listview after changing data using sharedpreferences

I'm trying to implement PreferenceFragmentCompat and SharedPreferences.OnSharedPreferenceChangeListener.
My app consists of main activity and fragments. The home fragment has a list of URLs with a title, and I would like to add a setting to add a URL to this list. This is what I've tried so far:
Here's the SettingsFragment.java:
#Override
public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
Preference preference = findPreference(key);
if (preference instanceof EditTextPreference) {
EditTextPreference editTextPreference = (EditTextPreference) preference;
String value = editTextPreference.getText();
new HomeFragment().addLink(value);
} else {
assert preference != null;
preference.setSummary(sharedPreferences.getString(key, ""));
}
}
And the HomeFragment.java:
private ArrayList<LinkItem> urls = new ArrayList<>(Arrays.asList(
new LinkItem("LifeHacker RSS Feed", "https://lifehacker.com/rss"),
new LinkItem("Google News Feed", "https://news.google.com/news/rss");
private LinkItemAdapter itemAdapter;
private ListView listView;
#Override
public View onCreateView(#NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_home, container, false);
listView = view.findViewById(R.id.postListView);
itemAdapter = new LinkItemAdapter(getActivity(), R.layout.link_item, urls);
listView.setAdapter(itemAdapter);
listView.setOnItemClickListener(onItemClickListener);
itemAdapter.notifyDataSetChanged();
return view;
}
void addLink(String title) {
urls.add(new LinkItem(title, "https://google.com"));
itemAdapter.notifyDataSetChanged();
}
private AdapterView.OnItemClickListener onItemClickListener = new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
HomeFragmentDirections.ActionHomeFragmentToRssFragment action =
HomeFragmentDirections.actionHomeFragmentToRssFragment(urls.get(position).Link, urls.get(position).Title);
NavHostFragment.findNavController(HomeFragment.this).navigate(action);
}
};
If I try doing it like this, the itemAdapter will be null, crashing the app, so I am unsure of how to implement this. If I try recreating it in addLink like in the onCreate method of HomeFragment, the activity ends up being null. If I try passing the activity or the context from settings fragment, the same result occurs.
LinkItemAdapter adapts the following object:
public class LinkItem {
public String Title;
public String Link;
}
My results so far have always been the same: crash as soon as I click "OK" on the edit text field after changing it, due to a null pointer. Could anyone help me out with this, please? I am new to android.
Stack trace:
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.myfragmentapp, PID: 5185
java.lang.NullPointerException: Attempt to invoke virtual method 'void com.example.myfragmentapp.adapters.LinkItemAdapter.notifyDataSetChanged()' on a null object reference
at com.example.myfragmentapp.screens.HomeFragment.addLink(HomeFragment.java:86)
at com.example.myfragmentapp.screens.SettingsFragment.onSharedPreferenceChanged(SettingsFragment.java:42)
at android.app.SharedPreferencesImpl$EditorImpl.notifyListeners(SharedPreferencesImpl.java:560)
at android.app.SharedPreferencesImpl$EditorImpl.apply(SharedPreferencesImpl.java:443)
at androidx.preference.Preference.tryCommit(Preference.java:1632)
at androidx.preference.Preference.persistString(Preference.java:1663)
at androidx.preference.EditTextPreference.setText(EditTextPreference.java:80)
at androidx.preference.EditTextPreferenceDialogFragmentCompat.onDialogClosed(EditTextPreferenceDialogFragmentCompat.java:99)
at androidx.preference.PreferenceDialogFragmentCompat.onDismiss(PreferenceDialogFragmentCompat.java:267)
at android.app.Dialog$ListenersHandler.handleMessage(Dialog.java:1377)
at android.os.Handler.dispatchMessage(Handler.java:105)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6709)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:769)

You should call addLink() after you've created the adapter:
public View onCreateView(#NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_home, container, false);
listView = view.findViewById(R.id.postListView);
itemAdapter = new LinkItemAdapter(getActivity(), R.layout.link_item, urls);
listView.setAdapter(itemAdapter);
listView.setOnItemClickListener(onItemClickListener);
addLnk();
return view;
}
If you're trying to set a value from one fragment to another you should either use callbacks or a ViewModel, the simpler of those being a callback:
Define a callback inteface:
interface OnSetPreferenceItem{
void setPrefItemInList(String item);
}
Inside SettingsFragment, define a variable:
private OnSetPreferenceItem callback;
In the same fragment, fill in the variable in onAttach:
public void onAttach(Context context) {
super.onAttach(context);
callback = (OnSetPreferenceItem )context;
}
Now instead of calling new HomeFragment().addLink(value);, call
callback.setPrefItemInList(value);
Let your parent activity implement that interface and implement the method suggested:
public void setPrefItemInList(String item){
homeFragment.addLink(item);
}
Modify your addLink method to protect it:
void addLink(String title) {
urls.add(new LinkItem(title, "https://google.com"));
if(itemAdapter!=null){
itemAdapter.notifyDataSetChanged();
}
}

I would suggest you using the lifecycle functions of the Fragment correctly. When you are modifying some data (i.e. adding a new URL in the list) from another fragment (i.e. SettingsFragment), you do not have to call the HomeFragment.addLink right away actually. Instead, you might consider having the onResume method implemented in your HomeFragment so that when you go back to your HomeFragment, the onResume function is called automatically and there you should update your list and consider calling notifyDataSetChanged on your adapter.
Hence I am trying to provide some pseudo code here. In your SettingsFragment do something like the following.
#Override
public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
Preference preference = findPreference(key);
if (preference instanceof EditTextPreference) {
EditTextPreference editTextPreference = (EditTextPreference) preference;
String value = editTextPreference.getText();
// new HomeFragment().addLink(value); // You do not call this here
saveTheNewURLInPrefrence(); // Just save the new value in your preference
} else {
assert preference != null;
preference.setSummary(sharedPreferences.getString(key, ""));
}
}
Now in your HomeFragment, implement the onResume function like the following.
#Override
protected void onResume() {
super.onResume();
urls = getAllItemsFromPreference();
if(itemAdapter != null) itemAdapter.notifyDataSetChanged();
else {
itemAdapter = new LinkItemAdapter(getActivity(), R.layout.link_item, urls);
listView.setAdapter(itemAdapter);
listView.setOnItemClickListener(onItemClickListener);
}
}
To understand more about fragment lifecycle, please check the documentation here. I hope you get the idea.

java.lang.IllegalStateException: Fragment not attached to a context

I have a tablayout with a viewpager in my MainActivity.
My PagerAdapter looks like this:
public class MainActivityPagerAdapter extends PagerAdapter {
public MainActivityPagerAdapter(FragmentManager fm, int numOfTabs) {
super(fm, numOfTabs);
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
return new StoresFragment();
case 1:
return new OrdersFragment();
default:
return null;
}
}
}
I am coming back from another activity like this:
Intent intent = new Intent(context, MainActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
finish(); //finishAffinity();
But then I get an java.lang.IllegalStateException in one of my Fragments in the viewpager of the MainActivity.
I read many related questions and tried to solve this. It is said, that this happens when one keeps references to Fragments outside of the PagerAdapter. But I am not doing this, as you can see in my code.
Does anyone know what I am doing wrong?
Edit - Stacktrace
FATAL EXCEPTION: main
Process: com.lifo.skipandgo, PID: 23665
java.lang.IllegalStateException: Fragment OrdersFragment{42c2a740} not attached to a context.
at android.support.v4.app.Fragment.requireContext(Fragment.java:614)
at android.support.v4.app.Fragment.getResources(Fragment.java:678)
at com.lifo.skipandgo.activities.fragments.OrdersFragment$1.results(OrdersFragment.java:111)
at com.lifo.skipandgo.connectors.firestore.QueryResult.receivedResult(QueryResult.java:37)
at com.lifo.skipandgo.controllers.UserController$2.onUpdate(UserController.java:88)
at com.lifo.skipandgo.connectors.firestore.QuerySubscription.onEvent(QuerySubscription.java:59)
at com.lifo.skipandgo.connectors.firestore.QuerySubscription.onEvent(QuerySubscription.java:18)
at com.google.firebase.firestore.zzg.onEvent(Unknown Source)
at com.google.firebase.firestore.g.zzh.zza(SourceFile:28)
at com.google.firebase.firestore.g.zzi.run(Unknown Source)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:146)
at android.app.ActivityThread.main(ActivityThread.java:5653)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1291)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1107)
at dalvik.system.NativeStart.main(Native Method)
Edit:
Interesting is, that the view has defenitely loaded when the error occurs. Because the error occurs about 10-15 seconds later after the fragment is shown again. I this in my orderFragment, where the error occurs:
orders = new QueryResult<UserOrder>(UserOrder.class) {
#Override
public void results(List<UserOrder> results) {
orderLoadingMessage.setBackgroundColor(getResources().getColor(R.color.green));
}
}
I do this in onCreateView and this result comes about 10-15 seconds after the view loaded.

The problem seems to be, that your fragment is listening to some events (via UserController and QueryResult) and these are fired before the fragment is attached to context.
Try to unregister the fragment when it becomes detached and to them again after attaching (LiveData can also help with this). Another way could be to receive and store the event while detached and only process it after attaching.

Use this before update your Activity UI :
if(isAdded())// This {#link androidx.fragment.app.Fragment} class method is responsible to check if the your view is attached to the Activity or not
{
// TODO Update your UI here
}

viewPager.offscreenPageLimit = (total number of fragments - 1)
viewPager.adapter = Adapter
Use this if your are using viewpager
And if you are using bottom navigation just simply check if(context != null)
But i suggest to use max 3 fragments in offscreenPageLimit

Some of your callbacks are being fired after your fragment is detached from activity. To resolve this issue you need to check whether your fragment is added before acting upon any callbacks. For example, change your orders object's initialization to this:
orders = new QueryResult<UserOrder>(UserOrder.class) {
#Override
public void results(List<UserOrder> results) {
if(isAdded()) {
orderLoadingMessage.setBackgroundColor(
getResources().getColor(R.color.green));
}
}
}

In my case this exception happened when I showed a DialogFragment and called it's methods. Because the fragment hasn't attached to a FragmentManager (this operation completes asynchronously) before calling methods, an application crashed.
val fragment = YourDialogFragment.newInstance()
fragment.show(fragmentManager, YourDialogFragment.TAG)
// This will throw an exception.
fragment.setCaptions("Yes", "No")
If you add the fragment with FragmentManager, you will get another exception: java.lang.IllegalArgumentException: No view found for id 0x1020002 (android:id/content) for fragment (or similar, if you use another id).
You can call fragment methods via post (or postDelayed), but it is a bad solution:
view?.post {
fragment.setCaptions("Yes", "No")
}
Currently I use childFragmentManager instead of fragmentManager:
val fragment = YourDialogFragment.newInstance()
fragment.show(childFragmentManager, YourDialogFragment.TAG)
fragment.setCaptions("Yes", "No")
I don't remember what I did, but now it works.

I had similar problem. I have solved it by following ferini's recommendation. I was using a live data which was firing before the context was attached.
Here is my full implementation
public class PurchaseOrderFragment extends Fragment {
FragmentPurchaseOrderBinding binding;
CurrentDenominationViewModel currentDenominationViewModel;
#Inject
ViewModelFactory viewModelFactory;
CurrentVoucherChangedObserver observer;
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
currentDenominationViewModel = new ViewModelProvider(requireActivity(),viewModelFactory).get(CurrentDenominationViewModel.class);
observer = new CurrentVoucherChangedObserver();
}
#Override
public View onCreateView(#NonNull LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
binding = DataBindingUtil.inflate(inflater,R.layout.fragment_purchase_order, container, false);
return binding.getRoot();
}
#Override
public void onViewCreated(#NonNull View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
currentDenominationViewModel.getCurrentVoucherStatisticsLiveData().observe(requireActivity(), observer);
}
#Override
public void onAttach(#NonNull Context context) {
AndroidSupportInjection.inject(this);
super.onAttach(context);
}
#Override
public void onDetach() {
super.onDetach();
currentDenominationViewModel.getCurrentVoucherStatisticsLiveData().removeObserver(observer);
}
final class CurrentVoucherChangedObserver implements Observer<VoucherStatistics> {
#Override
public void onChanged(VoucherStatistics x) {
String denomination = x.getDenomination()+"";
binding.tvDenomination.setText(denomination);
String stockAmount = requireContext().getResources().getString(R.string.StockAmount);
String text= "("+String.format(stockAmount,x.getQuantity()+"")+")";
binding.tvInStock.setText(text);
}
}
}

Your Solution
change your getItem() method to
switch (position) {
case 0:
return new StoresFragment();
case 1:
return new OrdersFragment();
default:
return null;
}

How to update custom RecyclerView from FragmentDialog?

I have an Activity A with a fragment frag2. Inside the fragment I have a RecyclerView and Adapter to show a list of custom class objects. Adding objects to the adapter is handled programmatically. I have a button inside TwoFragment that opens a FragmentDialog. I'd like to add an object to my Adapter by confirming this dialog, but it seems that the adapter is null when called from the FragmentDialog.
The same adapter is not null, and works if I call it from the fragment OnClick.
Moreover the adapter is null only after screen rotation, it works fine before rotating.
To communicate between the two Fragments I implement a communicator class in activity A.
Activity A
public void respond(String type) {
frag2.addSupport(type);
}
frag2
public RecyclerView rv;
public ArrayList<support> supports;
public myAdapter adapter;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
supports = new ArrayList<>();
adapter = new myAdapter(supports);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View layout = inflater.inflate( R.layout.fragment_two, container, false);
layout.setId(R.id.frag2);
if (savedInstanceState!=null)
{
supports = savedInstanceState.getParcelableArrayList("supports");
}
rv = (RecyclerView) layout.findViewById(R.id.rv);
adapter = new myAdapter(supports);
rv.setAdapter(myAdapter);
rv.setLayoutManager(new LinearLayoutManager(getActivity()));
rv.setItemAnimator(new DefaultItemAnimator());
#Override
public void onClick(View v) {
int id = v.getId();
switch (id){
case R.id.button1:
addSupport(type); // THIS WORKS ALWAYS, even after screen rotate
break;
case R.id.button2:
showDialog();
break;
}
}
public void showDialog(){
FragmentManager manager = getFragmentManager();
myDialog dialog = new myDialog();
dialog.show(manager, "dialog");
}
public void addSupport(String type){
adapter.addItem(new support(type)); // this line gives null pointer on adapter, but only if called after screen rotate and only if called from the dialog
}
dialog
communicator comm;
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.dialog, null);
comm = (myCommunicator) getActivity();
create = (Button) view.findViewById(R.id.button_ok);
create.setOnClickListener(this);
return view;
}
#Override
public void onClick(View v) {
if(v.getId()==R.id.button_ok)
{
// some controls to set type
comm.respond(type)
dismiss();
}
else {
dismiss();
}
myAdapter
public class myAdapter extends RecyclerView.Adapter<myAdapter.VH> {
private LayoutInflater inflater;
private ArrayList<support> data = new ArrayList<>();
// settings for viewholder
public myAdapter (ArrayList<support> data)
{
this.data=data;
}
public void addItem(support dataObj) {
data.add(dataObj);
notifyItemInserted(data.size());
}
}
logcat
FATAL EXCEPTION: main
java.lang.NullPointerException: Attempt to invoke virtual method 'myAdapter.addItem(myObject)' on a null object reference
I hope there are no mistakes, I shortened the code for better understanding. Keep in mind that everything works if I never rotate the screen.
I'm a beginner with android and I'm stuck with this for several days now. Please, help.

To understand the problem, it's as you say:
.. everything works if I never rotate the screen
So firstly to understand what happens on rotation, this is a quote from the Android Developer website:
Caution: Your activity will be destroyed and recreated each time the user rotates the screen. When the screen changes orientation, the system destroys and recreates the foreground activity because the screen configuration has changed and your activity might need to load alternative resources (such as the layout).
Ok, now to understand the error:
FATAL EXCEPTION: main
java.lang.NullPointerException: Attempt to invoke virtual method 'myAdapter.addItem(myObject)' on a null object reference
Essentially, in your dialog class, you have created a strong dependency by declaring :
comm = (myCommunicator) getActivity();
because comm references objects which would have been destroyed on rotation, hence the NullPointerException.
To further understand runtime changes, such as orientation changes, I'd recommend going through Handling Runtime Changes.
Update
Thank you for your answer, what would you recommend instead of comm = (myCommunicator) getActivity(); ?
The solution comes in 3 parts:
Make sure the onCreate of Activity A has the following:
#Override
public void onCreate(Bundle savedInstanceState) {
......
// find the retained fragment on activity restarts
FragmentManager fm = getFragmentManager();
frag2 = (Frag2) fm.findFragmentByTag(“frag2”);
// create frag2 only for the first time
if (frag2 == null) {
// add the fragment
frag2 = new Frag2();
fm.beginTransaction().add(frag2 , “frag2”).commit();
}
......
}
Add setRetainInstance(true) to the onCreate of frag2.
Remove the implicit referencing i.e. comm = (myCommunicator) getActivity();, and implement something more loosely coupled for dialog.
dialog
public interface Communicator {
void respond(String type);
}
Communicator comm;
....
public void addCommunicator(Communicator communicator) {
comm = communicator;
}
public void removeCommunicator() {
comm = null;
}
#Override
public void onClick(View v) {
if((v.getId()==R.id.button_ok) && (comm!=null))
{
// some controls to set type
comm.respond(type);
}
// Regardless of what button is pressed, the dialog will dismiss
dismiss();
}
This allows you do the following in frag2 (or any other class for that matter):
frag2
<pre><code>
public class Frag2 extends Fragment implements dialog.Communicator {
........
public void showDialog() {
FragmentManager manager = getFragmentManager();
myDialog dialog = new myDialog();
dialog.addCommunicator(this);
dialog.show(manager, "dialog");
}
#Override
public void respond(String type){
adapter.addItem(new support(type));
}
}

Sending string to Activity and then to a Fragment of Activity

I am having some trouble with my simple app. The app starts in the MainActivity where you can press a camera icon. This opens an implicit intent for taking a photo. When the photo is taken, another activity DisplayImageActivity is opened. This activity consists of two fragments: one that holds an ImageView for displaying the photo and another one that holds some TextViews that displays some information about the photo (filename, size, location etc.). I use a ViewPager for having horizontal swipe capabilities.
Now to the problem. I should note that this is not a consistent problem. Sometimes the app crashes, sometimes it works just fine. The problem lies in getting the image path from the onActivityResult in MainActivity to the two fragments so I can get the image and info. Here is my onActivityResult method:
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == 42 && resultCode == RESULT_OK) {
Log.d(TAG, "MainActivity onActivityResult method called.");
Intent intentShowPicture = new Intent(this, DisplayImageActivity.class);
intentShowPicture.putExtra(PICTURE_KEY, imgPath);
startActivity(intentShowPicture);
}
}
So I just put the image path I get from taking the picture in the bundle and start the DisplayImageActivity. Then in my DisplayImageActivity, I do this:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_display_image);
Log.d(MainActivity.TAG, "DisplayImageActivity onCreate called.");
imgPath = getIntent().getExtras().getString(MainActivity.PICTURE_KEY);
mAdapter = new FragmentAdapter(getSupportFragmentManager());
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mAdapter);
Then I have a method that just return the straing imgPath:
public String getImgPath() {
return imgPath;
}
Then inside the fragment (PictureFragment) I try to retrieve the imgPath like this:
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
DisplayImageActivity activity = (DisplayImageActivity) getActivity();
imgPath = activity.getImgPath();
But as I mentioned earlier, sometimes the getImgPath method just returns null and the app crashes when I try to retrieve the photo. But sometimes it works fine. I am kinda lost as to why this is. Is it because the fragment is sometimes constructed before the imgPath variable is assigned in the DisplayImageActivity, so the variable is just null?
I am kinda new to android, so this might not be the best approach. I just did it from the top of my head. Any ideas why this is happening?

If you want to pass data from an Activity to a Fragment, you could use this approach:
In the Activity:
Bundle bundle = new Bundle();
String imgPath = "path/to/my/image";
bundle.putString("imgPath", imgPath );
PictureFragment frag = new PictureFragment();
frag.setArguments(bundle);
transaction.replace(R.id.fragment_single, frag);
transaction.commit();
Fragment:
Reading the value in fragment
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
String myValue = this.getArguments().getString("imgPath");
...
...
...
}
For more information, take a look at this question How to pass a variable from Activity to Fragment, and pass it back?

Fragment Arguments are null

I am trying to send data from one fragment to another, I am using bundle for that. But, whenever, I try to get any information from that bundle in the second fragment, I get an error message saying that I am trying to get a null object. I have set the arguments of the second fragment before I create it, and I have also add information to the bundle before sending it. I could not find out what is the problem. Here is the interface code in the main fragment which should open the details fragment,
public interface ListClickHandler {
public void onlistElementClicked ( Bundle args); //we'll have to override it in the parent activity.
}//end interface.
public void onAttach(Activity activity) {
super.onAttach(activity);
// This makes sure that the container activity has implemented
// the callback interface. If not, it throws an exception
try {
mCallback = (ListClickHandler) activity;
}//end try
catch (ClassCastException e) {
throw new ClassCastException(activity.toString()
+ " must implement ListClickHandler interface");
}//end catch
}
Also, I create the bundle in two places, once in the main fragment, which contains a list, if any item is clicked the bundle is created, info is added to the bundle, and that bundle is passed to the method inside the interface as the following,
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_todo_list, container, false);
mSimpleCursorAdapter=new SimpleCursorAdapter(getActivity(),R.layout.notes_row,null, from, to,0);
getLoaderManager().initLoader(LOADER_ID, null, this); //once this is done onCreateLoader will be called.
ListView listView = (ListView) rootView.findViewById(R.id.notes_list); //findViewById must be called using the rootView because we are inside a fragment.
listView.setAdapter(mSimpleCursorAdapter);
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> adapterView, View view, int position, long l) {
Cursor cursor = mSimpleCursorAdapter.getCursor();
if (cursor != null && cursor.moveToPosition(position)) {
String category= cursor.getString(1);
String summary= cursor.getString(2);
String description=cursor.getString(3);
long id= cursor.getLong(cursor.getColumnIndex(NotesContract.NotesTable._ID));
int locationId= cursor.getInt(cursor.getColumnIndex(NotesContract.NotesTable.COLUMN_LOCATION));
String [] retrievedData= {category, summary, description};
if (getActivity().findViewById (R.id.fragment_container)!=null){
//two pane layout:
Bundle args = new Bundle();
args.putStringArray("data",retrievedData);
/*args.putInt("update", 1);*/
args.putLong("id", id);
args.putInt("locationId", locationId);
mCallback.onlistElementClicked(args );/*this is available in the parent activity*/
}
else {
// one pane layout:
Intent intent = new Intent(getActivity(), NotesDetails.class);
intent.putExtra(Intent.EXTRA_TEXT, retrievedData);
/*intent.putExtra("update", 1); */ //to indicate that the query should be update not insert.
intent.putExtra("id", id);
intent.putExtra("locationId", locationId); //whether it is 0 or 1
startActivity(intent);
}
}//end outer cursor if.
}
});
return rootView;
}
The second place where I create and call the bundle is in the main activity (which contains the main fragment) when some items of the options menu are selected as the following,
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {//open the settings activity to enable the user to change the settings.
//open settings activity via intent here.
startActivity(new Intent (this, Settings.class));
return true;
}
if (id==R.id.text_note){ //open the details activity where the user can enter their notes and save it.
if (twoPane) {
args.putBoolean("location", false);
mCallBack.onlistElementClicked(args);
}
else {
Intent intent = new Intent(this, NotesDetails.class);
startActivity(intent);
return true; //this line is necessary
}
}//end if
if (id==R.id.location_note)
{
if (twoPane) {
args.putBoolean("location", true);
mCallBack.onlistElementClicked(args);
}
else {
//prepare intent here:
Intent intent = new Intent(this, NotesDetails.class);
intent.putExtra("location", true);
startActivity(intent);
}
}
return super.onOptionsItemSelected(item);
}
This is how I override onlistElementClicked in the main activity,
#Override
public void onlistElementClicked(Bundle args) {
DetailsFragment detailsFragment = new DetailsFragment();
detailsFragment.setArguments(args);
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.fragment_container, detailsFragment);
transaction.addToBackStack(null);
// Commit the transaction
transaction.commit();
}//end interface method.
And this is how I get the information inside the arguments of the details fragment (The fragment that should be opened from the main fragment).
Bundle args=this.getArguments();
After that I use args to get any information in the bundle, but I am getting the error which I mentioned previously.
Can any one please help me? I've checked several solutions on the web and nothing worked for me.
Thank you.

You should assign the value of Bundle like this:
public void onCreate(Bundle savedInstance){
super.onCreate(savedInstance);
youtBandGlobalMember = getArguments();
}

Bundle args=this.getArguments();
actually, I didn't call it in any method, it is called in the body of fragment class, and its value is assigned to a global variable. Is that wrong?
It's too early. Member variables are initialized when the object is constructed and that is before you can call setArguments() on the fragment object.
Postpone the getArguments() call to one of the on...() lifecycle callbacks in the fragment.