android 获得后退键按事件

//获得后退键退出

public boolean onKeyDown(int keyCode, KeyEvent event) {

if (keyCode == KeyEvent.KEYCODE_BACK && event.getRepeatCount() == 0) {

//do something you want

return true;

}

return super.onKeyDown(keyCode, event);

}

获得后退键事件后，你可以做到事情很多喽～～～

比如说再按一次退出程序，网上的做法：

[java] view
plaincopy

private static Boolean isExit = false;

private static Boolean hasTask = false;

Timer tExit = new Timer();

TimerTask task = new TimerTask() {

@Override

public void run() {

isExit = false;

hasTask = true;

}

};

@Override

public boolean onKeyDown(int keyCode, KeyEvent event) {

System.out.println("TabHost_Index.java onKeyDown");

if (keyCode == KeyEvent.KEYCODE_BACK) {

if(isExit == false ) {

isExit = true;

Toast.makeText(this, "再按一次后退键退出应用程序", Toast.LENGTH_SHORT).show();

if(!hasTask) {

tExit.schedule(task, 2000);

}

} else {

finish();

System.exit(0);

}

}

return false;

}