onKeyDown-再按一次退出程序

public class MainActivity extends Activity { private long firstTime; private long secondTime; private long spaceTime;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);}@Overridepublic boolean onKeyDown(int keyCode, KeyEvent event) {if(keyCode==KeyEvent.KEYCODE_BACK){firstTime = System.currentTimeMillis();spaceTime = firstTime-secondTime;secondTime = firstTime;if(spaceTime>2000){Toast.makeText(MainActivity.this,"再按一次退出程序",Toast.LENGTH_SHORT).show();}elseMainActivity.this.finish();}return true;}}

通过两次点击返回键的时间判断是否退出程序。

原文链接：http://www.software8.co/wzjs/yidongkaifa/3046.html