Press two times to exit (exit the program once by pressing the key)

Private LongExittime = 0; @Override Public BooleanOnKeyDown (intKeyCode, KeyEvent event) {        if(KeyCode = =Keyevent.keycode_back&& event.getaction () = =Keyevent.action_down) {            if((System.currenttimemillis ()-Exittime) > 2000) {//System.currenttimemillis () No matter when it is called, it must be greater thanToast.maketext (Getapplicationcontext (),"Press one more time to exit the program", Toast.length_short). Show (); Exittime=System.currenttimemillis (); } Else{finish (); System.exit (0); }            return true; }        return Super. OnKeyDown (KeyCode, event); }

Define a global variable inside the class, such as long exittime = 0; just fine. It doesn't matter how much.

Press two times to exit (exit the program once by pressing the key)