按两次返回键退出程序和长按返回键退出程序

按两次返回键退出程序:

public class Exit {

 private boolean isExit = false;
 private Runnable task = new Runnable() {
     @Override
     public void run() {
         isExit = false;
     }
 };

 public void doExitInOneSecond() {
     isExit = true;
     HandlerThread thread = new HandlerThread("doTask");
     thread.start();
     new Handler(thread.getLooper()).postDelayed(task, 1000);
 }

 public boolean isExit() {
     return isExit;
 }

 public void setExit(boolean isExit) {
     this.isExit = isExit;
 }

Activity:

 public class Back2FinishAppActivity extends Activity {
     Exit exit = new Exit();

     /** Called when the activity is first created. */
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.main);
     }



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

           return super.onKeyDown(keyCode, event);
       }

     private void pressAgainExit() {
             if (exit.isExit()) {
                 finish();
             } else {
                 Toast.makeText(getApplicationContext(), "再按一次退出程序",
                         Toast.LENGTH_SHORT).show();
                 exit.doExitInOneSecond();
             }
         }
 }

长按返回键退出程序:

 public boolean dispatchKeyEvent(KeyEvent event)
     {
         int keyCode=event.getKeyCode();
         switch(keyCode)
         {
             case KeyEvent.KEYCODE_BACK: {
                  if(event.isLongPress())
                  {
                      this.stopService(intent);
                      System.exit(0);
                      return true;
                  }else
                  {
                      return false;

                  }
             }
         }
         return super.dispatchKeyEvent(event);

     }