¿Cómo volver a otra actividad incluso si no se creó en Android?

Assume I have two activities.
Activity A and Activity B, while Activity A is main activity.
There is a button in Activity A that will go to Activity B.
So, Activity A -> click -> Activity B and then click back button, it will go back to Activity A.
However, there is another story that I will have a GCM notification.
When clicking the notification, it will immediately go to Activity B.
Pero el problema es:

  1. If the application already run, when I click the notification and go to Activity B, and then click back button, it will correctly go back to Activity A.
  2. If I kill the application, and click the notification and go to Activity B, and then click back button, it will go to the Home Screen. But the problem is I want it will go back to Activity A.

¿Cómo resolver este problema?

preguntado el 24 de agosto de 12 a las 10:08

This might confuse the users. Goes against the Android "Pattern" . You could provide a separate button to go to Activity A? And let the Back Press do what it does. -

override onBackpressed in your Activity B and start your activity A from there then it will work in both use cases. -

2 Respuestas

Override you onBackPressed method and start the activity A using an intent.

@Override
public void onBackPressed() {
    // TODO Auto-generated method stub
    super.onBackPressed();
        // Start Activity A heres
}

Respondido 24 ago 12, 10:08

if Activity A already created, will it have some problems if I start the activity again? - jjlin

You can kill Activity A when moving to Activity B to ensure that you wont have that extra Activity. Just add finish(); after startActivity(). - Ninja perezoso

There is another way to find out the running activities too. You can try to see if Activity A is running or not. - Ninja perezoso

but the case is that I want to go back to Activity A if it exists, otherwise just create it. How to check? - jjlin

There are different ways to do it as listed here stackoverflow.com/questions/5446565/…. Like using a static value, .... - Ninja perezoso 

@Override
public void onBackPressed() {
// Don't forget to remove super.onBackPressed()
startActivity(new Intent(ActivityB.this,ActivityA.class));

}

Respondido 24 ago 12, 10:08

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