Bug in ActivityManger in android 2.1 when using long press on Home Key

In one of my services I fire an event that puts a notification in the status bar which includes a pending intent to start an activity when the user clicks the notification.

The activity I'm starting is actually a "popup" that has the theme of a dialog popup (android:theme="@android:style/Theme.Dialog") defined in the manifest. The code for the pending intent is below:

Intent intent = new Intent(this, PopupWindow.class);
PendingIntent launchIntent = PendingIntent.getActivity(context, 0 , intent, 0);

notificationManager开发者_C百科.notify(notificationRef, notification);

Everything works fine in android 2.2, but when testing in android 2.1, the newly started popup window doesn't take focus on the screen.

I know the activity is starting, because if I hold the home button down to bring up recently started apps, the "popup" will magically appear and takes focus.

Is there something I'm missing here? Why does my code work in android 2.2 and not 2.1?

After a day of debugging, I found that the new activity launched from the pending intent (Activity B in the stack) would get lost somewhere in the ActivityManager behind either the already opened activity (Activity A) or possibly the window of recently opened apps (long press on home key).

This happened ONLY if navigated away from Activity A with the use of a long-press on the home key ONLY in versions of android < 2.1. Every other instance of navigating away from Activity A (home key short-press, back-key press) would allow the pending intent on Activity B to open and take focus above everything on the screen. In android 2.2 and above, the code works absolutely fine with no issues. Very weird. To make things even weirder, if I put a Toast message to be displayed within the onRestart method of Activity A, the issue completely disappeared. There is nothing weird going on inside the onPause method of Activity A either....I still don't know.

I tried almost all flags on the pending intent for Activity B, but none of them would allow the popup to get to the top of the activity stack....I think Nanne and willytate put me on the right track...

I abandoned the method of setting the pending intent inside of a service, I think it was breaking the affinity between Activity A and Activity B. When I set the pending intent for Activity B inside of Activity A, as apposed to inside the service running in the background, Activity B (in the form of a popup via android:theme="@android:style/Theme.Dialog" in the manifest) would always appear at the top of the stack.

Once again, this "loss of focus" on an activity has only ever happened to me in this process:

1. Android 2.1
2. Launch Activity A
3. Use service to set status bar notification with a pending intent to start Activity B
4. Navigate away from Activity with long press on home key to any other application.
5. Service fires notification in status bar with intent to start Activity B.
6. Click notification to open Activity B.
7. Activity B, created as a dialog, is no where to be found and Activity A comes to the stop of the stack, but remains paused. No response to user touch at all on Activity A and the timer being displayed isn't moving. The Activity is stuck in onPause maybe?

The only way to get Activity B to appear is to, once again, long press the home key. When this is done, I see the following on the screen, in descending order with the first as the one at the top of the stack ready for user input :

1. List of recently used apps.
2. Activity B.
3. Acitivyt A.

Pressing the back button to dismiss the list of recently used apps will allow Activity B to take user input, and from there everything runs normally.

If this was not a complete waste of time, I did get a much better understanding on how Android handles the application stack.

Can anyone else (if they really wanted to) re-create this issue?