Android Notes-two ways to double-exit programs

First, you get the back key by OnKeyDown. If this is the next step.

One of the two methods is to determine whether to exit by determining the time between successive clicks of the back key, and the other is to set a status value to determine whether to exit by changing the status value.

1.

1     Private  LongExittime=0;//determine whether to exit based on time between consecutive clicks2 3 @Override4     protected voidonCreate (Bundle savedinstancestate) {5 super.oncreate (savedinstancestate);6 Setcontentview (r.layout.activity_main);7 8     }9 Ten @Override One      PublicBoolean OnKeyDown (intKeyCode, KeyEventEvent) { A  -         if(keycode==keyevent.keycode_back) { - exit (); the             return false; -         } -         returnSuper.onkeydown (KeyCode,Event); -     } +     /* - Judging by the time of the Click +     */ A  at     Private voidexit () { -         if(System.currenttimemillis ()-exittime> -){ -Toast.maketext (Getapplicationcontext (),"One more click to exit", Toast.length_short). Show (); -Exittime=System.currenttimemillis (); -}Else { - finish (); inSystem.exit (0); -         } to     }

2. Change the status value by sending a message with handler delay.

    Private StaticBoolean isexit=false;//determine whether to exit based on identityHandler Handler=NewHandler () {@Override Public voidhandlemessage (Message msg) {super.handlemessage (msg); Isexit=false;    }    }; @Overrideprotected voidonCreate (Bundle savedinstancestate) {super.oncreate (savedinstancestate);    Setcontentview (R.layout.activity_main); } @Override PublicBoolean OnKeyDown (intKeyCode, KeyEventEvent) {        if(keycode==keyevent.keycode_back)            {exit (); return false; }        returnSuper.onkeydown (KeyCode,Event); }    /** 1. Define whether an identity is highlighted **/    Private voidexit () {if(isexit) {isexit=true; Toast.maketext (Getapplicationcontext (),"One more click to exit", Toast.length_short). Show (); //send exit status with handler delayHandler.sendemptymessagedelayed (0, -); }Else{finish (); System.exit (0); }    }

Android Notes-two ways to double-exit programs