Android: Dialog etc restore after rotation changed

Question

How to restore the dialog etc after rotating the screen? For example, pop up an alertDialog to tell user some information. then the user rotate the screen to another orientation. How to restore the alertDialog? Can any one guide me to do it? Thanks!

Appended later:

I looked into the android source code and find these things:

Dialogs are stored in mManagedDialogs, and the related information is:

mManagedDialogs = new SparseArray<ManagedDialog>();

onSaveInstanceState related:

final void performSaveInstanceState(Bundle outState) {
    onSaveInstanceState(outState);
    saveManagedDialogs(outState);
}

In saveManagedDialogs, it has something to do with mManagedDialogs.

onRestoreInstanceState related:

final void performRestoreInstanceState(Bundle savedInstanceState) {
    onRestoreInstanceState(savedInstanceState);
    restoreManagedDialogs(savedInstanceState);
}

In restoreManagedDialogs, it has something to do with mManagedDialogs.

As you can see, for advanced feature, you must do the saving and restoring job by yourself. It may be a night mare when you have tons customized dialogs. I have not tried the complex dialog (has input EdiText, listView, say). In this way, I'd like to warn users: Never rotate the screen when inputing your info in the dialog... OR, lock the rotation dynamically when showing the dialog.

Thanks for all the people who answered me. Hope my information help you too.

Answer 1

The approach I took was to not allow the OS to restart your activity after the layout configuration change. To accomplish this, add this line within activities that you want to prevent from restarting in your manifest file:

 <activity
 android:configChanges="orientation|keyboard"
 ...
 >

Optionally, you can handle the configuration change in code in case there are some layout changes you want to make manually, such as reloading a new view from XML. This is done by overwriting the onConfigurationChanged() method in your Activity class:

@Override
public void onConfigurationChanged(Configuration newConfig)
{
    //Handle config changes here, paying attention to
    //the newConfig.orientation value
    super.onConfigurationChanged(newConfig);
}

Edit: Added "|keyboard" to the list of config changes

Answer 2

It is handled for you as long as you use Activity#showDialog to show it and Activity#onCreateDialog to create it: http://developer.android.com/reference/android/app/Activity.html#showDialog%28int%29

http://developer.android.com/reference/android/app/Activity.html#onCreateDialog%28int,%20android.os.Bundle%29

Answer 3

Add like this in your activity tag in manifest

<activity android:label="@string/app_name" android:configChanges="keyboardHidden|orientation|screenSize" android:name=".your.package"/>