How to clear the Android Stack of activities?

Question

I have an application with several Activities in Android and I want the user to be able to log-out by pressing a menu button. The problem I have is that

A) Android doesn't let you terminate the application and
B) even when I send the user to the LoginActivity again they can always press back and get right back to the previous activity they were in.

I already tried to launch the Activity with the two following flags:

Intent intent  = new Intent(this, LoginActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);        
startActivity(intent);

I also tried with each one of them by themselves.

I also tried calling finish() after startActivity(intent) as I read in another StackOverflow question.

Answer 1

In your login activity, override the back button, so it hides your app instead of finishing the activity:

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK) {
        moveTaskToBack(true);
        return true;
    }
    return super.onKeyDown(keyCode, event);
}

Also be sure to set android:alwaysRetainTaskState="true" on the root activity, so Android doesn't clear your stack (including the login activity) after 30min of inactivity from user.

Then just call finish() when there is a successful login.