Question

I have an Android app with 2 primary activities. When the app starts from scratch, both activities start and run just fine. Something like: A -> B. Activity A does all of the initialization needed for both A & B. All of my local testing on real hardware and emulator, A is always created (onCreate) before B is created.

However, on my app’s crash report, I see an exception which can only be explained by B being started without or before A. Is this possible? Will Android create an internal Activity without creating the other activities for my app (B without A)? Is the order of Activity creation guaranteed (A then B)? How would I re-create either of these scenarios using the emulator or real hardware?

I can easily move my initialization code to work regardless of which Activity is started first, BUT I wanted to learn how to reproduce and test before making changes. I looked through the documentation but it didn’t really help.

Here is the code that starts task B when user presses “play” button:

private void handlePlayTouch()
{
    Intent intent = new Intent(getApplicationContext(), PlayActivity.class);
    startActivity(intent);      
}

Answer 1

After you started Activity B, you press home button and make your application in the background. The system would kill your application if the free memory is very low. If you tried to switch to your application after your application killed, the system would try to restore your application and activity B without create A first.

You can use DDMMS’s Devices view to manually stop your application, there’s a red “stop process” button.Make sure that you should make your application in the background.