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IllegalStateException: Fragment FiltroOpcao not attached to a context.- Android Error

I'm trying get item selected from user to fragment formulary on my Android app, following the google documentation this is possible using this methods from the library, i tried implement this methods and your Interface in my DialogFragment and get it on my fragment formulary, but, the error is returned when i click on the button necessary to open Dialog Fragment.
This is my Dialog Fragment class:
public class FiltroOpcao extends DialogFragment {
OnFiltroEscolhido listener;
private final String[] filtroAnuncio = getResources().getStringArray(R.array.filtro_array);
#Override
public void onAttach(#NonNull Context context) {
super.onAttach(context);
try {
listener = (OnFiltroEscolhido) getTargetFragment();
}catch(ClassCastException e){
throw new ClassCastException(context.toString()+"Deve ser implementado");
}
}
#NonNull
#Override
public Dialog onCreateDialog(#Nullable Bundle savedInstanceState) {
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
builder.setTitle("Filtrar por:")
.setItems(R.array.filtro_array, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
listener.pegarFiltro(filtroAnuncio[which]);
}
});
return builder.create();
}
public interface OnFiltroEscolhido{
void pegarFiltro (String escolha);
}
}
And it is where i called the DialogFragment and the crash happens on my VendaFragment fragment class
public void onClick(View v) {
FiltroOpcao filtroOpcao = new FiltroOpcao();
filtroOpcao.setTargetFragment(VendaFragment.this, 1);
filtroOpcao.show(VendaFragment.this.getChildFragmentManager(), "FiltroOpcao");
}

private final String[] filtroAnuncio = getResources().getStringArray(R.array.filtro_array);
Probably, getResources() is the problem because you are using it before the fragment was attached.
Try to move the initialization of filtroAnuncio to onCreateDialog()
private String[] filtroAnuncio;
#NonNull
#Override
public Dialog onCreateDialog(#Nullable Bundle savedInstanceState) {
filtroAnuncio = getResources().getStringArray(R.array.filtro_array);
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
builder.setTitle("Filtrar por:")
.setItems(R.array.filtro_array, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
listener.pegarFiltro(filtroAnuncio[which]);
}
});
return builder.create();
}

Custom listener with interface

I am trying to understand better how to create a custom listener with a simple example but I don't know how to start the interface so that it is not null:
public class MainActivity extends AppCompatActivity implements ListenerButton{
TextView helloToOther;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
helloToOther = findViewById(R.id.helloWorldToOtherActivity);
helloToOther.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
startActivity(new Intent(MainActivity.this, ButtonActivity.class));
}
});
}
#Override
public void onClickButton(View view) {
Toast.makeText(this, "Estoy en la primera activity", Toast.LENGTH_SHORT).show();
}
}
This is the second activity:
public class ButtonActivity extends AppCompatActivity {
Button btnInterface;
ListenerButton listenerButton;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_button);
btnInterface = findViewById(R.id.button_activity__btn__button_interface);
setUpButtonInterface();
}
private void setUpButtonInterface() {
btnInterface.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
listenerButton.onClickButton(v);
}
});
}
}
And there's the interface:
public interface ListenerButton {
void onClickButton(View view);
}
Basically I get a null pointer exception on the second activity because the interface is null, but I don't fall right now as I can start it. Thank you very much.

the reason you are getting a null pointer exception is because you haven't assigned anything to variable listenerButton and therefor it is in fact null!!
you don't need a new interface for that you just need to do this:
public class ButtonActivity extends AppCompatActivity {
Button btnInterface;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_button);
btnInterface = findViewById(R.id.button_activity__btn__button_interface);
setUpButtonInterface();
}
private void setUpButtonInterface() {
btnInterface.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
//do whatever you want to do when button is clicked!
}
});
}
}
if you want to define whatever you want to do when button is clicked you need a class and not an interface:
public class ButtonListener implements View.OnClickListener{
#Override
public void onClick(View v) {
//do whatever you want to do when button is clicked!
}
}
and then in your activity do this:
public class ButtonActivity extends AppCompatActivity {
Button btnInterface;
ListenerButton listenerButton;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_button);
listenerButton = new ButtonListener();
btnInterface = findViewById(R.id.button_activity__btn__button_interface);
setUpButtonInterface();
}
private void setUpButtonInterface() {
btnInterface.setOnClickListener(listenerButton);
}
}

Create a new file:
MyListener.java:
public interface MyListener {
// you can define any parameter as per your requirement
public void callback(View view, String result);
}
In your activity, implement the interface:
MyActivity.java:
public class MyActivity extends Activity implements MyListener {
#override
public void onCreate(){
MyButton m = new MyButton(this);
}
// method is invoked when MyButton is clicked
#override
public void callback(View view, String result) {
// do your stuff here
}
}
In your custom class, invoke the interface when needed:
MyButton.java:
public class MyButton {
MyListener ml;
// constructor
MyButton(MyListener ml) {
//Setting the listener
this.ml = ml;
}
public void MyLogicToIntimateOthers() {
//Invoke the interface
ml.callback(this, "success");
}
}

Android how to Check if language has changed

I create an application with MVVM concept, there is fragment for viewpager in my Activity. some data changed when I change my language in my application, but the data that showed by webservices is not change. so I try to add android:configChanges="locale" in my every Activity and I already add this code on my Activity class :
#Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
recreate();
}
}
But its make my UI recreate every configuration change, including Screen Rotation while I just want to recreate if Language is changed.
this is my fragment code :
public class CatalogueFragment extends BaseFragment<FragmentCatalogueBinding, CatalogueViewModel>
implements CatalogueNavigator, CatalogueAdapter.CatalogueAdapterListener {
#Inject
CatalogueAdapter adapter;
#Inject
LinearLayoutManager mLayoutManager;
#Inject
ViewModelProvider.Factory factory;
FragmentCatalogueBinding fragmentCatalogueBinding;
private CatalogueViewModel catalogueViewModel;
public static CatalogueFragment newInstance(int Pos) {
Bundle args = new Bundle();
CatalogueFragment fragment = new CatalogueFragment();
fragment.setArguments(args);
return fragment;
}
#Override
public int getBindingVariable() {
return BR.viewModel;
}
#Override
public int getLayoutId() {
return R.layout.fragment_catalogue;
}
#Override
public CatalogueViewModel getViewModel() {
catalogueViewModel = ViewModelProviders.of(this, factory).get(CatalogueViewModel.class);
return catalogueViewModel;
}
#Override
public void handleError(String error) {
// handle error
}
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
catalogueViewModel.setNavigator(this);
adapter.setListener(this);
}
#Override
public void onRetryClick() {
catalogueViewModel.fetchData();
}
#Override
public void onViewCreated(#NonNull View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
fragmentCatalogueBinding = getViewDataBinding();
setUp();
}
#Override
public void updateData(List<Movie> movieList) {
adapter.addItems(movieList);
}
private void setUp() {
mLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
fragmentCatalogueBinding.recyclerCatalogue.setLayoutManager(mLayoutManager);
fragmentCatalogueBinding.recyclerCatalogue.setItemAnimator(new DefaultItemAnimator());
fragmentCatalogueBinding.recyclerCatalogue.setAdapter(adapter);
}
}
and this is my ViewModel class
public class CatalogueViewModel extends BaseViewModel {
private final MutableLiveData<List<Movie>> movieListLiveData;
public CatalogueViewModel(DataManager dataManager, SchedulerProvider schedulerProvider) {
super(dataManager, schedulerProvider);
movieListLiveData = new MutableLiveData<>();
fetchData();
}
public void fetchData() {
setIsLoading(true);
getCompositeDisposable().add(getDataManager()
.getApiHelper().doMovieCall(URLConfig.API_KEY, getDataManager().getLanguage())
.subscribeOn(getSchedulerProvider().io())
.observeOn(getSchedulerProvider().ui())
.subscribe(movieResponse -> {
if (movieResponse != null && movieResponse.getResults() != null) {
movieListLiveData.setValue(movieResponse.getResults());
}
setIsLoading(false);
}, throwable -> {
setIsLoading(false);
// getNavigator().handleError(throwable);
}));
}
public LiveData<List<Movie>> getMovieListLiveData() {
return movieListLiveData;
}
}
Can anybody show me where is my wrong? Thank you very much

You can use: ACTION_LOCALE_CHANGED
Here an example:
private BroadcastReceiver mLangReceiver = null;
protected BroadcastReceiver setupLangReceiver(){
if(mLangReceiver == null) {
mLangReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
// do what you want
}
};
registerReceiver(mLangReceiver, new IntentFilter(Intent.ACTION_LOCALE_CHANGED));
}
return mLangReceiver;
}

savedInstanceState causing a crash while screen rotation

public class CheatActivity extends AppCompatActivity {
private static final String EXTRA_ANSWER_IS_TRUE="com.example.ferhat.geoquiz.answer_is_true";
public static final String EXTRA_ANSWER_SHOWN="com.example.ferhat.geoquiz.answer_shown";
private static final String CHEATER="com.example.ferhat.geoquiz.cheated";
private Boolean mAnswerIsTrue;
private TextView mAnswerTextView;
private Button mShowAnswer;
private Boolean mIsCheater;
public static Intent newIntent(Context packageContext, boolean answerIsTrue){
Intent i=new Intent(packageContext,CheatActivity.class);
i.putExtra(EXTRA_ANSWER_IS_TRUE,answerIsTrue);
return i;
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_cheat);
mAnswerIsTrue = getIntent().getBooleanExtra(EXTRA_ANSWER_IS_TRUE, false);
mAnswerTextView = (TextView) findViewById(R.id.answerTextView);
mShowAnswer = (Button) findViewById(R.id.showAnswerButton);
mShowAnswer.setOnClickListener(new View.OnClickListener() {
//Cevabı gösteriyor ve Kopya çekildi bilgisi veriliyor
#Override
public void onClick(View v) {
if (mAnswerIsTrue) {
mAnswerTextView.setText(R.string.true_button);
} else {
mAnswerTextView.setText(R.string.false_button);
}
mIsCheater=true;
setAnswerShownResult();
}
});
if(savedInstanceState!=null){
mIsCheater=savedInstanceState.getBoolean(CHEATER,false);
}
}
private void setAnswerShownResult(){
Intent data=new Intent();
data.putExtra(EXTRA_ANSWER_SHOWN,mIsCheater);
setResult(RESULT_OK,data);
}
#Override
public void onSaveInstanceState(Bundle savedInstanceState){
super.onSaveInstanceState(savedInstanceState);
savedInstanceState.putBoolean(CHEATER,mIsCheater);
}
}
I try to solve challenge in Anroid Programming, Big Nerds Ranch Guide (Chap.5)
Challenge asks me to keep Cheat data while rotation of screen and transaction between questions.Main Activity holds questions and CheatActivity has answers from Main activity. And i created BooleanArray to hold cheat data for questions.
Problem is ,i cheated for first question and then when i am in the CheatActivity(CheatPage) of other questions ,program crashes if i rotate the screen.
Error caused by this line savedInstanceState.putBoolean(CHEATER,mIsCheater);
i think i need to clear data from previous Cheat Data(BooleanArray already holding it) but i dont know how to do it.

public class CheatActivity extends AppCompatActivity {
private static final String EXTRA_ANSWER_IS_TRUE = "com.example.ferhat.geoquiz.answer_is_true";
public static final String EXTRA_ANSWER_SHOWN = "com.example.ferhat.geoquiz.answer_shown";
public static final String EXTRA_CHEATED = "com.example.ferhat.geoquiz.cheated";
private static final String CHEATER = "com.example.ferhat.geoquiz.cheated";
private Boolean mAnswerIsTrue;
private TextView mAnswerTextView;
private Button mShowAnswer;
private Boolean mAnswerEverShown;
private Boolean twoStep=false;
//Yeni intent methodu yarattık Cevabı alıyor ve bu activity i başlatıyor
public static Intent newIntent(Context packageContext, boolean answerIsTrue, boolean checked) {
Intent i = new Intent(packageContext, CheatActivity.class);
i.putExtra(EXTRA_ANSWER_IS_TRUE, answerIsTrue);
i.putExtra(EXTRA_CHEATED, checked);
return i;
}
private void setAnswerShownResult(Boolean isAnswerShown) {
Intent data = new Intent();
**if(mAnswerEverShown) {
isAnswerShown=mAnswerEverShown;
data.putExtra(EXTRA_ANSWER_SHOWN, isAnswerShown);
setResult(RESULT_OK, data);
}else {
data.putExtra(EXTRA_ANSWER_SHOWN, isAnswerShown);
setResult(RESULT_OK, data);
}
twoStep=isAnswerShown;**
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_cheat);
mAnswerIsTrue = getIntent().getBooleanExtra(EXTRA_ANSWER_IS_TRUE, false);
mAnswerTextView = (TextView) findViewById(R.id.answerTextView);
**mAnswerEverShown = getIntent().getBooleanExtra(EXTRA_CHEATED, false);**
mShowAnswer = (Button) findViewById(R.id.showAnswerButton);
mShowAnswer.setOnClickListener(new View.OnClickListener() {
//Cevabı gösteriyor ve Kopya çekildi bilgisi veriliyor
#Override
public void onClick(View v) {
if (mAnswerIsTrue) {
mAnswerTextView.setText(R.string.true_button);
} else {
mAnswerTextView.setText(R.string.false_button);
}
twoStep=true;
setAnswerShownResult(twoStep);
}
});
**if (savedInstanceState != null) {
setAnswerShownResult(savedInstanceState.getBoolean(CHEATER, false));
}
}
#Override
public void onSaveInstanceState (Bundle savedInstanceState){
super.onSaveInstanceState(savedInstanceState);
savedInstanceState.putBoolean(CHEATER, twoStep);
}
}**
i found solution like for every situation.
first think i did; i get info from main activity
mAnswerEverShown = getIntent().getBooleanExtra(EXTRA_CHEATED, false);
And Then i changed setAnswerShownResult for two situation.If it is not cheated ever program sends current data(cheated or not).
i marked where i changed with *.

You need to putBoolean before callback the super method.
#Override
public void onSaveInstanceState(Bundle savedInstanceState){
savedInstanceState.putBoolean(CHEATER,mIsCheater);
super.onSaveInstanceState(savedInstanceState);
}
if not the CHEATER won't be saved and you can't call it when resume activity

Implement DialogFragment interface in OnClickListener

I need to build a DialogFragment which returns user input from the dialog to an activity.
The dialog needs to be called in an OnClickListener which gets called when an element in a listview gets clicked.
The return value of the DialogFragment (the input of the user) should be directly available in the OnClickListener in the activity.
I tried to implement this by sticking to the official docs: http://developer.android.com/guide/topics/ui/dialogs.html#PassingEvents
I need something like the following which doesn't work since I don't know how to make the anonymous OnClickListener implement the interface of the CustomNumberPicker class.
As far as I know implementing the interface is necessary in order to get data from the DialogFragment back to the Activity.
Main Activity:
public class MainAcitivity extends ActionBarActivity {
[...]
// ArrayAdapter of the Listview
private class ListViewArrayAdapter extends ArrayAdapter<Exercise> {
public ListViewArrayAdapter(Context context, ArrayList<Exercise> exercises) {
super(context, 0, exercises);
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
[...]
if (convertView == null) {
convertView = LayoutInflater.from(getContext()).inflate(R.layout.item_workoutdetail, parent, false);
}
TextView tvSets = (TextView) convertView.findViewById(R.id.tvWorkoutExerciseSets);
tvSets.setText(sets.toString());
// OnClickListener for every element in the ListView
tvSets.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// This is where the Dialog should be called and
// the user input from the Dialog should be returned
DialogFragment numberpicker = new CustomNumberPicker();
numberpicker.show(MainActivity.this.getSupportFragmentManager(), "NoticeDialogFragment");
}
// Here I would like to implement the interface of CustomNumberPicker
// in order to get the user input entered in the Dialog
});
return convertView;
}
}
}
CustomNumberPicker (basically the same as in the docs):
public class CustomNumberPicker extends DialogFragment {
public interface NoticeDialogListener {
public void onDialogPositiveClick(DialogFragment dialog);
public void onDialogNegativeClick(DialogFragment dialog);
}
// Use this instance of the interface to deliver action events
NoticeDialogListener mListener;
// Override the Fragment.onAttach() method to instantiate the NoticeDialogListener
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
// Verify that the host activity implements the callback interface
try {
// Instantiate the NoticeDialogListener so we can send events to the host
mListener = (NoticeDialogListener) activity;
} catch (ClassCastException e) {
// The activity doesn't implement the interface, throw exception
throw new ClassCastException(activity.toString()
+ " must implement NoticeDialogListener");
}
}
#Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
// Use the Builder class for convenient dialog construction
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
builder.setMessage("Sets")
.setPositiveButton("set", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
// Return stuff here to the activity?
}
})
.setNegativeButton("cancle", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
// User cancelled the dialog
}
});
// Create the AlertDialog object and return it
return builder.create();
}
}

Something like this?
public class CustomNumberPicker extends DialogFragment {
private NoticeDialogListener ndl;
public interface NoticeDialogListener {
public void onDialogPositiveClick(DialogFragment dialog);
public void onDialogNegativeClick(DialogFragment dialog);
}
//add a custom constructor so that you have an initialised NoticeDialogListener
public CustomNumberPicker(NoticeDialogListener ndl){
super();
this.ndl=ndl;
}
//make sure you maintain an empty constructor
public CustomNumberPicker( ){
super();
}
// Use this instance of the interface to deliver action events
NoticeDialogListener mListener;
// Override the Fragment.onAttach() method to instantiate the NoticeDialogListener
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
//remove the check that verfis if your activity has the DialogListener Attached because you want to attach it into your list view onClick()
}
#Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
// Use the Builder class for convenient dialog construction
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
builder.setMessage("Sets")
.setPositiveButton("set", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
ndl.onDialogPositiveClick(dialog);
}
})
.setNegativeButton("cancle", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
ndl.onDialogNegativeClick(dialog);
}
});
// Create the AlertDialog object and return it
return builder.create();
}
}
and then your listView onClick becomes:
tvSets.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// This is where the Dialog should be called and
// the user input from the Dialog should be returned
//
//
DialogFragment numberpicker = new CustomNumberPicker(new NoticeDialogListener() {
#Override
public void onDialogPositiveClick(DialogFragment dialog) {
//What you want to do incase of positive click
}
#Override
public void onDialogNegativeClick(DialogFragment dialog) {
//What you want to do incase of negative click
}
};);
numberpicker.show(MainActivity.this.getSupportFragmentManager(), "NoticeDialogFragment");
}
// Here I would like to implement the interface of CustomNumberPicker
// in order to get the user input entered in the Dialog
});
Do read the comments I have added.And it can even be further optimized because you really dont need an entire dialog instance to get the values you need.
EDIT a possible optimization could be:
Changing the Listener interface to :
public interface NoticeDialogListener {
public void onDialogPositiveClick(String output);
public void onDialogNegativeClick(String output);
//or whatever form of output that you want
}
Then modify the implemented methods accordingly.

You should have your activity, implement your interface (NoticeDialogListener).
public class MainActivity extends ActionBarActivity implements
NoticeDialogListener{
#Override
public void onDialogPositiveClick(DialogFragment dialog){
//Do something
}
#Override
public void onDialogNegativeClick(DialogFragment dialog){
//Do some other things
}
[...]
}
Then in your button click listeners of the dialog, you use the mListener and call the methods, which is now implemented in the activity and the code will be executed there.
builder.setMessage("Sets")
.setPositiveButton("set", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
if(mListener != null)
mListener.onDialogPositiveClick(CustomNumberPicker.this);
}
});
Also note that you should set the mListener to null in the onDetach() method of your DialogFragment.
#Override
public void onDetach() {
super.onDetach();
mListener = null;
}

Here's how it's done:
In the Activity where you show the DiaogFragment, set the arguments of the DialogFragment with the desired name value pair.
Also make sure that the activity implements the DialogInterface.OnClickListener
In the overridded onClick pick up the value from the aforementioned name value pair
public class MainActivity extends AppCompatActivity implements DialogInterface.OnClickListener {
private static SettingsFragment settingsFragment;
private Button btnSettings;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_activity);
btnSettings = (Button) findViewById(R.id.btnSettings);
btnSettings.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
settingsFragment = new SettingsFragment();
Bundle bundle = new Bundle();
bundle.putString("myKey", null);
settingsFragment.setArguments(bundle);
//Use the commented out line below if you want the click listener to return to a fragment instead of an activity
//assuming that this class in a fragment and not an activity
//rotateSettingsFragment.setTargetFragment(getActivity().getSupportFragmentManager().findFragmentByTag("TagForThisFragment"), 0);
settingsFragment.setTargetFragment(settingsFragment, 0);
settingsFragment.setCancelable(true);
settingsFragment.show(getSupportFragmentManager(), "SettingsFragment");
}
});
}
#Override
public void onClick(DialogInterface dialog, int which) {
if(getResources().getResourceEntryName(which).equals("btnSettingFragmentClose")) {
String myValue = settingsFragment.getArguments().getString("myKey");
dialog.dismiss();
}
}
}
In your DialogFragment declare a DialogInterface.OnClickListener and cast it to the activity in the onAttach.
In the event that needs to send back the data to the activity; set the buddle arguments and then call the onClickListener.onClick
public class SettingsFragment extends DialogFragment {
private View rootView;
private Button btnSettingFragmentClose;
private DialogInterface.OnClickListener onClickListener;
public SettingsFragment() {}
/* Uncomment this and comment out on onAttach when you want to return to a fragment instead of an activity.
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
onClickListener = (DialogInterface.OnClickListener) getTargetFragment();
}
*/
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
rootView = inflater.inflate(R.layout.fragment_settings, container, false);
btnSettingFragmentClose = (Button) rootView.findViewById(R.id.btnSettingFragmentClose);
btnSettingFragmentClose.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
getArguments().putString("myKey", "Hello World!");
onClickListener.onClick(getDialog(), v.getId());
}
});
return rootView;
}
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
onClickListener = (DialogInterface.OnClickListener) activity;
}
catch (ClassCastException e) {
throw new ClassCastException(activity.toString() + " must implement mainFragmentCallback");
}
}
}

This simple solution works for me:
public class MyActivity implements MyDialogFragment.Listener {
// ...
#Override
public void onMyEvent() {
// do something here
}
}
public class MyDialogFragment extends DialogFragment {
private Listener mCallback;
public interface Listener {
void onMyEvent();
}
#SuppressLint("RestrictedApi")
#Override
public void setupDialog(final Dialog dialog, int style) {
super.setupDialog(dialog, style);
View contentView = View.inflate(getContext(), R.layout.dialog_fragment_custom, null);
dialog.setContentView(contentView);
mCallback = (Listener) getActivity();
Button myBtn = (Button) dialog.findViewById(R.id.btn_custom);
myBtn.setOnClickListener(v -> {
mCallback.onMyEvent();
dismiss();
});
}
}

As an example you can use DatePickerDialog where DatePickerDialog.OnDateSetListener used to deliver result.
or this is one of my implementations that allow to keep dialog screen open until user not finished with some action or not entered valid data. With custom callback that provide exact interface to this dialog.
public class ConfirmPasswordDialog extends DialogFragment {
private OnPaswordCheckResult resultListener;
private TextView passwordView;
public ConfirmPasswordDialog(OnPaswordCheckResult resultListener){
this.resultListener = resultListener;
}
#Override
public android.app.Dialog onCreateDialog(Bundle savedInstanceState) {
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
LayoutInflater inflater = getActivity().getLayoutInflater();
View dialogView = inflater.inflate(R.layout.dialog_layout, null);
builder.setView(dialogView);
passwordView = (TextView) dialogView.findViewById(R.id.password);
passwordView.addTextChangedListener(new TextWatcher() {
#Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {/*do nothing*/}
#Override
public void onTextChanged(CharSequence s, int start, int before, int count) {/*do nothing*/}
#Override
public void afterTextChanged(Editable s) {
if(passwordView != null){
passwordView.setError(null);
}
}
});
builder.setView(dialogView);
builder.setMessage("Please enter password to finish with action");
builder.setPositiveButton("Confirm", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
/* do something when click happen, in this case mostly like dummy because data return later
* after validation or immediately if required*/
}
});
builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
builder.setTitle("Confirm password");
final AlertDialog dialog = builder.create();
dialog.setOnShowListener(new DialogInterface.OnShowListener() {
#Override
public void onShow(final DialogInterface dialogInterface) {
Button positiveButton = dialog.getButton(DialogInterface.BUTTON_POSITIVE);
positiveButton.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View view) {
if(passwordView == null || !isAdded()){
return;
}
String password = passwordView.getText().toString();
if(PrefUtils.isPasswordValid(getActivity(), password)){
if(resultListener == null){
return;
}
/* Return result and dismiss dialog*/
resultListener.onValidPassword();
dialog.dismiss();
} else {
/* Show an error if entered password is invalid and keep dialog
* shown to the user*/
String error = getActivity().getString(R.string.message_password_not_valid);
passwordView.setError(error);
}
}
});
}
});
return dialog;
}
/**
* Custom callback to return result if entered password is valid
*/
public static interface OnPaswordCheckResult{
void onValidPassword();
}
}