prevent activity appearing Several times

Question

When the first back is hit, it goes back to 3 which is MainActivity. The second back goes to 1 which is MainActivity again.

That is, MainActivity is repeated twice, which is not interesting!

I want exit the app wherever there was MainActivity and back pressed.

Answer 1

use this code on which activity you want to close app on back button pressed

@Override
public void onBackPressed() {
    finishAffinity();
}