安卓按两次返回退出程序

只需要在activity中重写onKeyDown.事件(代码如下)

@Overridepublic boolean onKeyDown(int keyCode, KeyEvent event) {if (keyCode == KeyEvent.KEYCODE_BACK&& event.getAction() == KeyEvent.ACTION_DOWN) {if ((System.currentTimeMillis() - exitTime) > 2000) {//中间间隔的时间,可设定Toast.makeText(getApplicationContext(), "再按一次退出程序",Toast.LENGTH_SHORT).show();exitTime = System.currentTimeMillis();} else {// finish();System.exit(0);}return true;}return super.onKeyDown(keyCode, event);}