Develop Reference

How to close the alert dialog explicitly?

In my activity, I am loading some eight fragments, from the 8th fragment showing some alert dialog.After that session getting expired, so redirected them to the first fragment without user interaction.During that time alert dialog not getting closed which created from 8 fragments.

In the onPause() of your 8th Fragment you should hide the AlertDialog.
class XYZ extends Fragment{
//Keep the reference to AlertDialog as a member variable in your Fragment
AlertDialog mDialog;
//other member declarations ...
#Override
public void onPause() {
// check if dialog is not null and is already showing
if(mDialog !=null && mDialog.isHowing())
mDialog.hide();
super.onPause();
}
Note : If the viewpager removes 8th fragment from memory and some action that you perform in your dialog references your 8th fragment then it would cause null pointer exception.

If you using alert dialog like that:
AlertDialog.Builder builder = new AlertDialog.Builder(Activity);
you need to keep the dialog instance which returns from the show method and call dismiss from that instance.
AlertDialog dialog = builder.show();
//Use this anywhere to close
dialog.dismiss();

Fragment and DialogFragment Lifecycle Relationship

I have Fragment "A" where I have an ImageButton in place. Upon clicking this button a DialogFragment "B" is called to the foreground where Fragment "A" is partially visible in the background. DialogFragment "B" presents the user with a list of choices. Upon clicking a specific choice DialogFragment "B" is dismissed via Dismiss() and Fragment "A" becomes fully visible again.
During this action I need to update the ImageButton on Fragment "A" to represent the user's choice made on DialogFragment "B" (basically a new image for the ImageButton).
Am I correct in thinking the right place to update the ImageButton on Fragment "A" is during OnResume? Does Fragment "A" go into OnPause while FragmentDialog "B" is being shown? Therefore upon returning from DialogFragment "B", Fragment "A" would trigger its OnResume and that's where I should make the update changes to the ImageButton being presented to the user?
I hope my explanation is clear. Any detailed help on where and how I should be updating the ImageButton would be highly appreciated.

With the addition of ViewModels and LiveData solving this problem just got easier. Create a viewModel which both fragments reference. Put the next line in the OnCreate of the fragments. Can also be in onCreateDialog of the dialogfragment.
myViewModel = ViewModelProviders.of(getActivity()).get(MyViewModel.class);
When the dialog is dismissed, call a method on myViewModel, which updates a LiveData variable:
dialogBuilder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
myViewModel.setButtonPressed(PositiveButtonPressed);
}
});
dialogBuilder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
myViewModel.setButtonPressed(NegativeButtonPressed)
}
});
In the viewModel the method sets a MutuableLiveData variable for example to the image to be shown.
void SetButtonPressed(int buttonPressed){
if (buttonPressed==positiveButtonPressed){
imageToBeShown.setValue(image A);
}
else{
imageToBeShown.setValue(image B);
}
}
Set an observer to LiveData variable in onActivityCreated:
myViewModel.imageToBeShown().observe(getViewLifecycleOwner(), new Observer<Image>() {
#Override
public void onChanged(#Nullable Image image) {
button.setBackground(image);
}
}
});
Of course you can implement a getter method and keep the MutuableLiveData variable private. The observer then just obeserves the getter methode.

I had same problem when tried with Interface-Callback method but OnResume of Fragment didn't got triggered when DialogFragment was dismissed since we are not switching to other activity.
So here Event Bus made life easy. Event Bus is the easiest and best way to make communication between activities and fragments with only three step, you can see it here
This is nothing but publish/subscribe event bus mechanism. You will get proper documentation here
Add EventBus dependency to your gradle file -
compile 'org.greenrobot:eventbus:x.x.x'
OR
compile 'org.greenrobot:eventbus:3.1.1' (Specific version)
For the above scenario -
Create one custom POJO class for user events -
public class UserEvent {
public final int userId;
public UserEvent(int userId) {
this.userId = userId;
}
}
Subscribe an event in Fragment A whenever it is posted/published from DialogFragment or from somewhere else -
#Subscribe(threadMode = ThreadMode.MAIN)
public void onUserEvent(UserEvent event) {
// Do something with userId
Toast.makeText(getActivity(), event.userId, Toast.LENGTH_SHORT).show();
}
Register or Unregister your EventBus from your Fragment A's lifecycle especially in onStart and onStop respectively -
#Override
public void onStart() {
super.onStart();
EventBus.getDefault().register(this);
}
#Override
public void onStop() {
EventBus.getDefault().unregister(this);
super.onStop();
}
In the end, on clicking specific item, Publish/Post your event from DialogFragment -
EventBus.getDefault().post(new MessageEvent(user.getId()));

Fragment A won't go into onPause so onResume won't get called
http://developer.android.com/guide/components/fragments.html
Resumed
The fragment is visible in the running activity.
Paused
Another activity is in the foreground and has focus, but the activity
in which this fragment lives is still visible (the foreground activity
is partially transparent or doesn't cover the entire screen).

Callback When DialogFragment is Dismissed

I want to launch a dialog with a custom layout, which I've implemented via a DialogFragment. (I basically just changed onCreateView() and added button handlers). The dialog lets the user quickly change an important setting.
This dialog will be launched from several different activities. The different activities don't have much in common, except that they need to refresh after the user makes a change to the setting. They don't need to get any information from the dialog; they merely need to know when it's closed (dismissed).
What I've Tried
I tried having the activity refresh in onResume(), but launching and dismissing a dialog never seems to call this method. (So I'm not sure why it even exists, but that's probably a topic for another question.)
Next, I tried adding a DialogInterface.OnDismissListener to the dialog:
public static void showMyDialog(OnDismissListener listener, Activity activity)
{
DialogFragment fragment = new MyDialogFragment();
fragment.show(activity.getFragmentManager(), "date");
activity.getFragmentManager().executePendingTransactions();//A
fragment.getDialog().setOnDismissListener(listener);//B
}
When I originally left out the line A, I got a NullPointerException on line B because the dialog is null at that point. Following the advice of this SO answer, I put in the call to executePendingTransaction(). This causes an IllegalStateException on line B, with the message "OnDismissListener is already taken by DialogFragment and cannot be replaced." I also tried putting setOnDismissListener() before the call to show(), but that always caused a NullPointerException.
I then read this other SO answer, which says the original asker was "calling getDialog() too early in the DialogFragment's life cycle." So I tried adding a constructor to my DialogFragment:
public MyDialogFragment(SomeCallback illTakeAnythingICanGet)
{
//I'll store the callback here and call it later
}
Unfortunately, adding a constructor made Android Lint freak out with a fatal warning, and when I looked it up, I found a comment in this question that seems to say this approach will make it impossible to deal with the user rotating the screen while the dialog is open.
The Question
How can an activity figure out when a DialogFragment has closed (been dismissed) in a way that won't break my app if the user rotates the screen? Should I be using something else besides a DialogFragment?

This is just a longer explanation of harism's comment in case anyone else has the same problem I did.
You can accomplish what I wanted by creating an interface like this:
public interface MyDialogCloseListener
{
public void handleDialogClose(DialogInterface dialog);//or whatever args you want
}
Have the activity that launches your dialog (DialogFragment) implement this interface. Then give that DialogFragment the following method:
public void onDismiss(DialogInterface dialog)
{
Activity activity = getActivity();
if(activity instanceof MyDialogCloseListener)
((MyDialogCloseListener)activity).handleDialogClose(dialog);
}

More explanatory code for someone to do the same.
Create the interface as:
package com.example.dialoglistener;
import android.content.DialogInterface;
public interface MyDialogCloseListener {
public void handleDialogClose(DialogInterface dialog);
}
Implement the interface in activity as:
MyDialogCloseListener closeListener = new MyDialogCloseListener() {
#Override
public void handleDialogClose(DialogInterface dialog) {
//do here whatever you want to do on Dialog dismiss
}
};
Write a DismissListener in DialogFragement as
public void DismissListener(MyDialogCloseListener closeListener) {
this.closeListener = closeListener;
}
call DismissListener from your activity as:
dialogFragementObject.DismissListener(closeListener);
and finally write onDismiss method
#Override
public void onDismiss(DialogInterface dialog) {
super.onDismiss(dialog);
if(closeListener != null) {
closeListener.handleDialogClose(null);
}
}

Tyler's example was the only example I could find that actually worked. The only thing that needs changed for the example to work is the call to the DismissListner method in the DialogFragment class. He has it as:
dialogFragementObject.DismissListner(closeListener);
This just needs to be a cast to whatever your class name of that DialogFragment is. For example:
((MyDialogFragment)dialogFragementObject).DismissListner(closeListener);

Android: What is the proper way of connecting dialog buttons with an activity?

Here is what I would like to do:
1) Inside an Activity a dialog is shown. I use DialogFragment and FragmentManager for this, by calling:
dialogFragment.show(fragmentManager, "edit_task_list");
2) Inside the Dialog I have layout with a custom Button. I would like to perform some action when the button is clicked and later close the dialog.
How should I connect everything? I see two options:
1) onclick attribute in the Button and a method inside the Actvity. That was my original plan, but I don't how to get the Dialog from the Activity to dismiss it. Even if this is not the right way, how could this be done? I would like to understand how this works.
2) set on click listener on the button when the Dialog is created in DialogFragment. This will require me to pass some context from the Activity to the DialogFragment, so I would like to avoid it (and keep the DialogFragment as simple as possible).
Which of those options should I take?

Number 2 Doesn't require you to pass any context (and you shouldn't). You define an interface that can act as a contract between fragments and activities and make your activity implement it.
From your dialog and in your button.onClick(), you do something like this (untested code):
if ( getActivity() != null
&& !getActivity().finishing()
&& getActivity() instanceOf YourInterface) {
((YourInterface)getActivity()).onSomeNiceMethod();
dismiss(); // close the dialog (if this is what you want).
}
The interface looks like:
public interface YourInterface {
void onSomeNiceMethod();
}
And your Activity…
public class YourActivity implements YourInterface {
void onSomeNiceMethod() {
// Hey! The Button In The Dialog Has Been Pressed!
}
}

All Activity and Fragment classes have a built-in callback method for you to use when you start another Activity, Fragment, Dialog, or DialogFragment.
void onActivityResult(int requestCode, int resultCode, Intent data)
Since you want to start the Dialog from an Activity, using the Dialog class is better than the DialogFragment class. The latter is better for starting a dialog from a Fragment, because it has two methods for communicating back to the Fragment (get/set TargetFragment())
The Dialog class has the getOwnerActivity() method. This is the Activity you use when creating the Dialog with one of its constructors.
You set a onClickListener on the button in the Dialog class. To pass the result back to the Activity:
getOwnerActivity().onActivityResult(intIdentifyingme, Activity.RESULT_OK,
intent);
dismiss(); // close the dialog
You put additional info you want to send in an Intent.

1) onclick attribute in the Button and a method inside the Actvity.
That was my original plan, but I don't how to get the Dialog from the
Activity to dismiss it. Even if this is not the right way, how could
this be done? I would like to understand how this works.
Basically your Activity has to remember/know which dialog is active at the moment with something like curDialog=dialogFragment;, then when handling the button onclick action you'll know which dialog to dismiss. But this is really not a good idea since basically the Button View would "leak" from your DialogFragment to your Activity, which breaks object encapsulation.
2) set on click listener on the button when the Dialog is created in
DialogFragment. This will require me to pass some context from the
Activity to the DialogFragment, so I would like to avoid it (and keep
the DialogFragment as simple as possible).
As a previous answer mentioned, you don't need to pass any Context to it, especially since you can get the Activity by calling getActivity().
The solution depends on whether or not this dialog would be used by multiple Activities:
Used by a single Activity: #Martin's solution will work just fine
Used by multiple Activity: abstraction can be used such that only the user's decision is passed to a listener. This is a (modified) solution I came up for the same problem:
public class BaseDialogFragment extends DialogFragment {
protected TextView dialogEn;
protected Button dialogYes;
private Button dialogNo;
protected OnSelectListener listener;
public interface OnSelectListener {
public void onSelect(int type, boolean yes);
}
public void setOnSelectListener(OnSelectListener listener) {
this.listener = listener;
}
public BaseDialogFragment() {
super();
}
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.dialog_confirm, container, false);
dialogYes = (Button) v.findViewById(R.id.yes);
dialogNo = (Button) v.findViewById(R.id.no);
dialogEn = (TextView) view.findViewById(R.id.dialog_en);
dialogEn.setText(getArguments().getString("text_en"));
dialogYes.setOnClickListener(this);
dialogNo.setOnClickListener(this);
return v;
}
public void onClick(View v) {
if (listener != null) {
listener.onSelect(getArguments().getInt("type"),
v == dialogYes ? true : false);
}
getDialog().dismiss();
}
}
To use it some additional info needs to be provided:
Bundle bundle = new Bundle();
bundle.putInt("type", type); //type: an unique integer value that helps differentiate result from different dialogs
bundle.putString("text_en", en); //en: String to be displayed
dialog.setArguments(bundle);
dialog.setOnSelectListener(this);
So if the type value above is set to 115, then a dialogYes button click would trigger public void onSelect(int type, boolean yes) method to be called with 115 and true as the 1st & 2nd parameters.

Your first point about the onClick attribute in the xml should be avoided. Because handling a Dialog that way could be really painfull if you respect events like screen rotation or a setup with multiple dialogs. This leads into leaked window errors most of the time and needs unnecessary code overhead to avoid this. Because you have to keep track of the Dialog which is actually shown yourself.
To be able to dismiss the Dialog this way you can use the Tag you setted as you called dialogFragment.show(fragmentManager, "edit_task_list");
DialogFragment frag = (DialogFragment)getFragmentManager().findFragmentByTag("edit_task_list");
if(frag != null)
frag.dismiss();
The proper solution is to use an interface as a callback for the communication between the DialogFragment and the Activity. This keeps the Dialog modular and the code easy. Here is an example from the docs. For this you don't need a Context. You simply pass the interface to the dialog in the onAttach() callback. It has a reference of the Activity as a parameter, which called that Dialog.
// Example interface for the communication
public interface OnArticleSelectedListener {
public void onButtonClicked(/*any Parameters*/);
}
public static class FragmentA extends DialogFragment {
OnArticleSelectedListener mListener;
...
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
mListener = (OnArticleSelectedListener) activity; // get the interface of the Activity
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString()
+ " must implement OnArticleSelectedListener");
}
}
...
}
Handle the Button click in the Dialog and call dismiss() in it, that the Dialog can dismiss itself. Have a look at this question why to use dismiss() instead of getDialog().dismiss().
yourButton.setOnClickListener(new OnClickListener(){
#Override
public void onClick(View v){
if(mListener != null) // check if the listener is still valid
mListener.onButtonClicked(...); // calls the Activity implementation of this callback
dismiss(); // dismiss the Dialog
}
});
In onPause() of the Dialog set the reference of the interface to null. This way you can be sure that the callback will only be used if the Dialog is showing.
Your Activity looks something like this to be able to handle the callback:
public class MyActivity extends Activity implements OnArticleSelectedListener{
...
#Override
public void onButtonClicked(...){
// your implementation here
}
}
I don't know your overall setup but if you would use an AlertDialog a click on the Buttons dismiss the Dialog automatically when the method returns.

Closing multiple Dialogs at once

Im writing an Android application in which a user selection triggers a custom Dialog, from which a selection may trigger a second Dialog.
When showing the initial Dialog from the Activity class, I'm setting an onDismissListener on it to pull out user selections which works fine other in cases where the 2nd Dialog is not triggered. The issue that I'm having is that I can't figure out how to have the first one Dialog remain open until the 2nd one is dismissed, so that the information from both is sent back to the Activity class.
Hopefully some code will make this a little more clear:
MainActivity class where I am launching the initial CustomDialog:
customDialog = new CustomDialog(this);
customDialog.show();
customDialog.setOnDismissListener(new OnDismissListener(){
public void onDismiss(DialogInterface di){
slection = customDialog.getselection();
updateUI(); //updates a listview with the results
}
});
Within the CustumDialog class where I am launching the SecondDialog on top of it:
if(specify){
SecondDialog secondDialog = new SecondDialog(context);
secondDialog.show();
secondDialog.setOnDismissListener( new OnDissmissListener(){
public void onDismiss(DialogInterface di){
// this is where I want to call the CustomDialog's dismiss() method
// so that they both close at the same time and the data from here
// can be sent back to the MainActiivty through the CustomDialog's
// onDismissListener
}
});
}
dismiss();
So, to reiterate: I'm trying to prevent the CustomDialog's dismiss() method to be called until the SecondDialog is also dismissed. Is there a way that I can call it from the SecondDialog's OnDismissListener?

You should create customDialog as an instance level variable. You then it will be accessible with onDismiss(...) of second dialog. There you can call customDialog.dismiss();
// Instance level variable
private Dialog customDialog = null;
Instanciate your customDialog, then create second dialog from within your customDialog. Your Second dialog's code would look like this.
if(specify){
SecondDialog secondDialog = new SecondDialog(context);
secondDialog.show();
secondDialog.setOnDismissListener( new OnDissmissListener(){
public void onDismiss(DialogInterface di){
// customDialog is accessible as it is declared as instance level variable
MyClassName.this.customDialog.dismiss();
}
});
}
dismiss();

I prefer to save the data in 1st dialog before going to send one and when dismiss the 2nd dialog, open the 1st dialog again with saved data .. i used this way in my developing and its effective ..