在 Android 中防止屏幕旋转时对话框被取消

小开

If you're changing the layout on orientation change I wouldn't put android:configChanges="orientation" in your manifest because you're recreating the views anyway.

Save the current state of your activity (like text entered, shown dialog, data displayed etc.) using these methods:

@Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
}


@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
super.onRestoreInstanceState(savedInstanceState);
}

That way the activity goes through onCreate again and afterwards calls the onRestoreInstanceState method where you can set your EditText value again.

If you want to store more complex Objects you can use

@Override
public Object onRetainNonConfigurationInstance() {
}

Here you can store any object and in onCreate you just have to call getLastNonConfigurationInstance(); to get the Object.

小开

A very easy approach is to create the dialogs from the method onCreateDialog() (see note below). You show them through showDialog(). This way, Android handles the rotation for you and you do not have to call dismiss() in onPause() to avoid a WindowLeak and then you neither have to restore the dialog. From the docs:

Show a dialog managed by this activity. A call to onCreateDialog(int, Bundle) will be made with the same id the first time this is called for a given id. From thereafter, the dialog will be automatically saved and restored.

See Android docs showDialog() for more info. Hope it helps somebody!

Note: If using AlertDialog.Builder, do not call show() from onCreateDialog(), call create() instead. If using ProgressDialog, just create the object, set the parameters you need and return it. In conclusion, show() inside onCreateDialog() causes problems, just create de Dialog instance and return it. This should work! (I have experienced issues using showDialog() from onCreate() -actually not showing the dialog-, but if you use it in onResume() or in a listener callback it works well).

小开

最佳答案

The best way to avoid this problem nowadays is by using a DialogFragment.

Create a new class which extends DialogFragment. Override onCreateDialog and return your old Dialog or an AlertDialog.

Then you can show it with DialogFragment.show(fragmentManager, tag).

Here's an example with a Listener:

public class MyDialogFragment extends DialogFragment {


public interface YesNoListener {
void onYes();


void onNo();
}


@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
if (!(activity instanceof YesNoListener)) {
throw new ClassCastException(activity.toString() + " must implement YesNoListener");
}
}


@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
return new AlertDialog.Builder(getActivity())
.setTitle(R.string.dialog_my_title)
.setMessage(R.string.dialog_my_message)
.setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {


@Override
public void onClick(DialogInterface dialog, int which) {
((YesNoListener) getActivity()).onYes();
}
})
.setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {


@Override
public void onClick(DialogInterface dialog, int which) {
((YesNoListener) getActivity()).onNo();
}
})
.create();
}
}

And in the Activity you call:

new MyDialogFragment().show(getSupportFragmentManager(), "tag"); // or getFragmentManager() in API 11+

This answer helps explain these other three questions (and their answers):

小开

// Prevent dialog dismiss when orientation changes
private static void doKeepDialog(Dialog dialog){
WindowManager.LayoutParams lp = new WindowManager.LayoutParams();
lp.copyFrom(dialog.getWindow().getAttributes());
lp.width = WindowManager.LayoutParams.WRAP_CONTENT;
lp.height = WindowManager.LayoutParams.WRAP_CONTENT;
dialog.getWindow().setAttributes(lp);
}

public static void doLogout(final Context context){
final AlertDialog dialog = new AlertDialog.Builder(context)
.setIcon(android.R.drawable.ic_dialog_alert)
.setTitle(R.string.titlelogout)
.setMessage(R.string.logoutconfirm)
.setPositiveButton("Yes", new DialogInterface.OnClickListener()
{
@Override
public void onClick(DialogInterface dialog, int which) {
...
}


})
.setNegativeButton("No", null)
.show();


doKeepDialog(dialog);
}

小开

You can combine the Dialog's onSave/onRestore methods with the Activity's onSave/onRestore methods to keep the state of the Dialog.

Note: This method works for those "simple" Dialogs, such as displaying an alert message. It won't reproduce the contents of a WebView embedded in a Dialog. If you really want to prevent a complex dialog from dismissal during rotation, try Chung IW's method.

@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
super.onRestoreInstanceState(savedInstanceState);
myDialog.onRestoreInstanceState(savedInstanceState.getBundle("DIALOG"));
// Put your codes to retrieve the EditText contents and
// assign them to the EditText here.
}


@Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
// Put your codes to save the EditText contents and put them
// to the outState Bundle here.
outState.putBundle("DIALOG", myDialog.onSaveInstanceState());
}

小开

This question was answered a long time ago.

Yet this is non-hacky and simple solution I use for myself.

I did this helper class for myself, so you can use it in your application too.

Usage is:

PersistentDialogFragment.newInstance(
getBaseContext(),
RC_REQUEST_CODE,
R.string.message_text,
R.string.positive_btn_text,
R.string.negative_btn_text)
.show(getSupportFragmentManager(), PersistentDialogFragment.TAG);

Or

 PersistentDialogFragment.newInstance(
getBaseContext(),
RC_EXPLAIN_LOCATION,
"Dialog title",
"Dialog Message",
"Positive Button",
"Negative Button",
false)
.show(getSupportFragmentManager(), PersistentDialogFragment.TAG);










public class ExampleActivity extends Activity implements PersistentDialogListener{


@Override
void onDialogPositiveClicked(int requestCode) {
switch(requestCode) {
case RC_REQUEST_CODE:
break;
}
}


@Override
void onDialogNegativeClicked(int requestCode) {
switch(requestCode) {
case RC_REQUEST_CODE:
break;
}
}
}

小开

Just add android:configChanges="orientation" with your activity element in AndroidManifest.xml

Example:

<activity
android:name=".YourActivity"
android:configChanges="orientation"
android:label="@string/app_name"></activity>

小开

Just use

ConfigurationChanges = Android.Content.PM.ConfigChanges.Orientation | Android.Content.PM.ConfigChanges.ScreenSize

and app will know how to handle rotation and screen size.

小开

Definitely, the best approach is by using DialogFragment.

Here is mine solution of wrapper class that helps to prevent different dialogs from being dismissed within one Fragment (or Activity with small refactoring). Also, it helps to avoid massive code refactoring if for some reasons there are a lot of AlertDialogs scattered among the code with slight differences between them in terms of actions, appearance or something else.

public class DialogWrapper extends DialogFragment {
private static final String ARG_DIALOG_ID = "ARG_DIALOG_ID";


private int mDialogId;


/**
* Display dialog fragment.
* @param invoker  The fragment which will serve as {@link AlertDialog} alert dialog provider
* @param dialogId The ID of dialog that should be shown
*/
public static <T extends Fragment & DialogProvider> void show(T invoker, int dialogId) {
Bundle args = new Bundle();
args.putInt(ARG_DIALOG_ID, dialogId);
DialogWrapper dialogWrapper = new DialogWrapper();
dialogWrapper.setArguments(args);
dialogWrapper.setTargetFragment(invoker, 0);
dialogWrapper.show(invoker.getActivity().getSupportFragmentManager(), null);
}


@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mDialogId = getArguments().getInt(ARG_DIALOG_ID);
}


@NonNull
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
return getDialogProvider().getDialog(mDialogId);
}


private DialogProvider getDialogProvider() {
return (DialogProvider) getTargetFragment();
}


public interface DialogProvider {
Dialog getDialog(int dialogId);
}
}

When it comes to Activity you can invoke getContext() inside onCreateDialog(), cast it to the DialogProvider interface and request a specific dialog by mDialogId. All logic to dealing with a target fragment should be deleted.

Usage from fragment:

public class MainFragment extends Fragment implements DialogWrapper.DialogProvider {
private static final int ID_CONFIRMATION_DIALOG = 0;


@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
Button btnHello = (Button) view.findViewById(R.id.btnConfirm);
btnHello.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
DialogWrapper.show(MainFragment.this, ID_CONFIRMATION_DIALOG);
}
});
}


@Override
public Dialog getDialog(int dialogId) {
switch (dialogId) {
case ID_CONFIRMATION_DIALOG:
return createConfirmationDialog(); //Your AlertDialog
default:
throw new IllegalArgumentException("Unknown dialog id: " + dialogId);
}
}
}

You can read the complete article on my blog How to prevent Dialog being dismissed? and play with the source code.

小开

I had a similar problem: when the screen orientation changed, the dialog's onDismiss listener was called even though the user didn't dismiss the dialog. I was able to work around this by instead using the onCancel listener, which triggered both when the user pressed the back button and when the user touched outside of the dialog.

小开

It seems that this is still an issue, even when "doing everything right" and using DialogFragment etc.

There is a thread on Google Issue Tracker which claims that it is due to an old dismiss message being left in the message queue. The provided workaround is quite simple:

    @Override
public void onDestroyView() {
/* Bugfix: https://issuetracker.google.com/issues/36929400 */
if (getDialog() != null && getRetainInstance())
getDialog().setDismissMessage(null);


super.onDestroyView();
}

Incredible that this is still needed 7 years after that issue was first reported.

小开

In case nothing helps, and you need a solution that works, you can go on the safe side, and each time you open a dialog save its basic info to the activity ViewModel (and remove it from this list when you dismiss dialog). This basic info could be dialog type and some id (the information you need in order to open this dialog). This ViewModel is not destroyed during changes of Activity lifecycle. Let's say user opens a dialog to leave a reference to a restaurant. So dialog type would be LeaveReferenceDialog and the id would be the restaurant id. When opening this dialog, you save this information in an Object that you can call DialogInfo, and add this object to the ViewModel of the Activity. This information will allow you to reopen the dialog when the activity onResume() is being called:

// On resume in Activity
override fun onResume() {
super.onResume()
    

// Restore dialogs that were open before activity went to background
restoreDialogs()
}

Which calls:

    fun restoreDialogs() {
mainActivityViewModel.setIsRestoringDialogs(true) // lock list in view model


for (dialogInfo in mainActivityViewModel.openDialogs)
openDialog(dialogInfo)


mainActivityViewModel.setIsRestoringDialogs(false) // open lock
}

When IsRestoringDialogs in ViewModel is set to true, dialog info will not be added to the list in view model, and it's important because we're now restoring dialogs which are already in that list. Otherwise, changing the list while using it would cause an exception. So:

// Create new dialog
override fun openLeaveReferenceDialog(restaurantId: String) {
var dialog = LeaveReferenceDialog()
// Add id to dialog in bundle
val bundle = Bundle()
bundle.putString(Constants.RESTAURANT_ID, restaurantId)
dialog.arguments = bundle
dialog.show(supportFragmentManager, "")
        

// Add dialog info to list of open dialogs
addOpenDialogInfo(DialogInfo(LEAVE_REFERENCE_DIALOG, restaurantId))
}

Then remove dialog info when dismissing it:

// Dismiss dialog
override fun dismissLeaveReferenceDialog(Dialog dialog, id: String) {
if (dialog?.isAdded()){
dialog.dismiss()
mainActivityViewModel.removeOpenDialog(LEAVE_REFERENCE_DIALOG, id)
}
}

And in the ViewModel of the Activity:

fun addOpenDialogInfo(dialogInfo: DialogInfo){
if (!isRestoringDialogs){
val dialogWasInList = removeOpenDialog(dialogInfo.type, dialogInfo.id)
openDialogs.add(dialogInfo)
}
}




fun removeOpenDialog(type: Int, id: String) {
if (!isRestoringDialogs)
for (dialogInfo in openDialogs)
if (dialogInfo.type == type && dialogInfo.id == id)
openDialogs.remove(dialogInfo)
}

You actually reopen all the dialogs that were open before, in the same order. But how do they retain their information? Each dialog has a ViewModel of its own, which is also not destroyed during the activity lifecycle. So when you open the dialog, you get the ViewModel and init the UI using this ViewModel of the dialog as always.

小开

Yes, I agree with the solution of using DialogFragment given by @Brais Gabin, just want to suggest some changes to the solution given by him.

While defining our custom class that extends DialogFragment, we require some interfaces to manage the actions ultimately by the activity or the fragment that has invoked the dialog. But setting these listener interfaces in the onAttach(Context context) method may sometimes cause ClassCastException that may crash the app.

So to avoid this exception, we can create a method to set the listener interfaces and call just it after creating the object of the dialog fragment. Here is a sample code that could help you understand more-

AlertRetryDialog.class

    public class AlertRetryDialog extends DialogFragment {


public interface Listener{
void onRetry();
}


Listener listener;


public void setListener(Listener listener)
{
this.listener=listener;
}


@NonNull
@Override
public Dialog onCreateDialog(@Nullable Bundle savedInstanceState) {
AlertDialog.Builder builder=new AlertDialog.Builder(getActivity());
builder.setMessage("Please Check Your Network Connection").setPositiveButton("Retry", new
DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
//Screen rotation will cause the listener to be null
//Always do a null check of your interface listener before calling its method
if(listener!=null&&listener instanceof HomeFragment)
listener.onRetry();
}
}).setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
}
});
return builder.create();
}


}

And in the Activity or in the Fragment you call-

                   AlertRetryDialog alertRetryDialog = new AlertRetryDialog();
alertRetryDialog.setListener(HomeFragment.this);
alertRetryDialog.show(getFragmentManager(), "tag");

And implement the methods of your listener interface in your Activity or the Fragment-

              public class YourActivity or YourFragment implements AlertRetryDialog.Listener{
                

//here's my listener interface's method
@Override
public void onRetry()
{
//your code for action
}
                

}

Always make sure that you do a null check of the listener interfaces before calling any of its methods to prevent NullPointerException (Screen rotation will cause the listener interfaces to be null).

Please do let me know if you find this answer helpful. Thank You.