Android Double Baclk Press

doubleBackpress.java

private static long back_pressed = 0L;
 
@Override
public void onBackPressed()
{
    if (back_pressed + 2000 > System.currentTimeMillis()) super.onBackPressed();
    else Toast.makeText(getBaseContext(), "Press once again to exit!", Toast.LENGTH_SHORT).show();
    back_pressed = System.currentTimeMillis();
}