Question

The phone back button has me baffled. This question has been asked many times, but i have NOT got the solution. So asking again as per my requirement.

I have a home screen activity
It calls 3 activities – which in turn calls 2 activity each.

Assume i navigate this way

Home > Act1 > SubAct1a > SubAct1b > Home (through a Home button) > Act2 > Home > Act3

Now in Act3, when i press the phone BACK button, i get to Home. My REQUIREMENT at this point is when i press the BACK button again , it should EXIT the app. But what happens it it goes like this

Act2 > Home > SubAct1b > SubAct1a > Act1 > Home > EXIT

So the user is pressing BACK MULTIPLE times before he quits the app.

Pressing the HOME key is an option, but i want the BACK to work correctly as well.

I have this piece of code in the HOME activity – but it does not work at all

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK) {
        finish();
        System.exit(0);
    }

    return super.onKeyDown(keyCode, event);
}

It just returns to the previous activity it was at.

Answer 1

You should return true, to tell the system that you already handled this situation,

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK) {
        finish();
        System.exit(0);
        return true;
    }

    return super.onKeyDown(keyCode, event);
}

When you start your home activity, try setting the clear top flag…

Intent intent = new Intent(this, HomeActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);