Change intent extras for back navigation intent

Question

I have an app with the following flow (all activities in the same app):

• Activity A starts activity B with startActivity. It may add a boolean "autoContinue"=true extra.
• When activity B starts, it checks the "autoContinue" flag in onCreate with getIntent().hasExtra("autoContinue"). If the flag is true, it immediately starts activity C with startActivity.

Now I have two scenarios for pressing the back button in activity C:

• If activity B is still in the activity stack and was not destroyed, everything is fine. Activity C closes and activity B comes into view.
• If I leave activity C by pressing the home button and do some other things before returning to activity C, activity B is often destroyed. Now when I press the back button in activity C, activity B will be created with the Intent that has "autoContinue"=true and immediately start activity C again.

I tried removing the flag from the Intent in activity B's onCreate, but it doesn't work:

final Intent intent = getIntent();
final Bundle extras = intent.getExtras();
if (extras.containsKey("autoContinue")) {
    intent.removeExtra("autoContinue");
    continue();
}

How can I remove the "autoContinue"=true flag from the intent extras when navigating back from activity C?

Answer 1

You can pass extras to previous activity while finishing if you have started the activity with startActivityForResult method. See the following code example:

public void finishActivity() {
        Intent returnIntent = new Intent();
        returnIntent.putExtra("KEY", "Value");
        getActivity().setResult(Activity.RESULT_OK, returnIntent);
        getActivity().finish();    
}

Also, I want to recommend you not hard code the keys. Read the blog post that I have written on this topic.

Answer 2

You're on the right track in removing the extra from the intent. However the Intent associated with the Activity still has the extra in it. You need to call setIntent() after removing the extra. So your code will look like this:

final Intent intent = getIntent();
final Bundle extras = intent.getExtras();
if (extras.containsKey("autoContinue")) {
    intent.removeExtra("autoContinue");
    setIntent(intent);
    continue();
}