Question

I have following 2 activities(plus many more not important for this question):

<activity android:name=".activities.HomeActivity" android:excludeFromRecents="true" />
<activity android:name=".activities.AdHocActivity" android:noHistory="true"/>  

HomeActivity is a first one and only one wich I keep history for. User can go differnt places from Home and click Back to come back to main HomeActivity.

I also have service running on alarm and checking for some specific things. When specific criteria met I’m displaying my AdHocActivity

Intent i = new Intent(context, AdHocActivity.class);
                i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                i.putExtra(BlockingActivity.INTENT_BLOCKED_PACKAGE_NAME, packageName);
                context.startActivity(i);

FLAG_ACTIVITY_NEW_TASK was necessary to show Activity from BroadcastReceiver

Now, this AdHoc activity displays some message to user and has a button to take user back to HomeActivity

private void sendToMainApplication()
    {
        Intent i = new Intent(this, HomeActivity.class);
        startActivity(i);
        finish();
    }

All this work, but I get second instance of HomeActivity in a stack. So now when user taps “Back” – my Home activity flashes and comes back (previous copy).

I want only one copy to stay on top. I want it to be like anchor one. If it doesn’t exist – I want new one to be opened.

Answer 1

The trick to prevent HomeActivity from being doubled was to call it like this:

private void sendToMainApplication()
    {
        Intent i = new Intent(this, HomeActivity.class);
        i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        startActivity(i);
        finish();
    }