记安卓中倒计时代码

以30分钟为例写的一个倒计时：

直接上代码

public class MainActivity extends AppCompatActivity {

private int minute = 30;//这是分钟
    private int second = 0;//这是分钟后面的秒数。这里是以30分钟为例的，所以，minute是30，second是0
    private TextView timeView;
    private Timer timer;
    private TimerTask timerTask;
    //这是接收回来处理的消息
    private Handler handler = new Handler() {
public void handleMessage(Message msg) {
if (minute == 0) {
if (second == 0) {
timeView.setText("Time out !");
                    if (timer != null) {
timer.cancel();
                        timer = null;
                    }
if (timerTask != null) {
timerTask = null;
                    }
                } else {
second--;
                    if (second >= 10) {
timeView.setText("0" + minute + ":" + second);
                    } else {
timeView.setText("0" + minute + ":0" + second);
                    }
                }
            } else {
if (second == 0) {
second = 59;
                    minute--;
                    if (minute >= 10) {
timeView.setText(minute + ":" + second);
                    } else {
timeView.setText("0" + minute + ":" + second);
                    }
                } else {
second--;
                    if (second >= 10) {
if (minute >= 10) {
timeView.setText(minute + ":" + second);
                        } else {
timeView.setText("0" + minute + ":" + second);
                        }
                    } else {
if (minute >= 10) {
timeView.setText(minute + ":0" + second);
                        } else {
timeView.setText("0" + minute + ":0" + second);
                        }
                    }
                }
            }
        }

    };


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        timeView = (TextView) findViewById(R.id.tv);

        timeView.setText(minute + ":" + second);

        timerTask = new TimerTask() {

@Override
            public void run() {
                Message msg = new Message();
                msg.what = 0;
                handler.sendMessage(msg);
            }
        };

        timer = new Timer();
        timer.schedule(timerTask, 0, 1000);

    }

@Override
    protected void onDestroy() {
if (timer != null) {
timer.cancel();
            timer = null;
        }
if (timerTask != null) {
timerTask = null;
        }
minute = -1;
        second = -1;
        super.onDestroy();
    }

@Override
    protected void onStart() {
super.onStart();
    }

@Override
    protected void onStop() {
super.onStop();
    }

@Override
    protected void onResume() {
super.onResume();
    }

@Override
    protected void onRestart() {
super.onRestart();
    }

@Override
    protected void onPause() {
super.onPause();
    }
}

ok，这就完成了