android 定时器开始继续暂停停止 (2)

最新推荐文章于 2025-09-10 16:45:12 发布

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本文详细介绍了如何在Android应用程序中使用定时器进行操作，包括如何启动、继续、暂停和停止定时任务。内容涵盖Java语言在Android开发中的应用，为开发者提供了实用的代码示例。

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    TextView tv_stop,tv_pause,tv_restart,tv_start,tv_num;
    MyHandler myHandler;
    Timer timer;
    private  boolean isOnpause;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();
        myHandler=new MyHandler(this);
        timer=new Timer();
    }
    private void initView() {
        tv_stop=findViewById(R.id.tv_stop);
        tv_pause= findViewById(R.id.tv_pause);
        tv_restart=findViewById(R.id.tv_restart);
        tv_start=findViewById(R.id.tv_start);
        tv_num=findViewById(R.id.tv_num);
        tv_stop.setOnClickListener(this);
        tv_pause.setOnClickListener(this);
        tv_restart.setOnClickListener(this);
        tv_start.setOnClickListener(this);
    }
    public int countDown=-1;
    EmptyMessageTask mCountdownTask;
    @Override
    public void onClick(View view) {
        isOnpause=false;
        switch (view.getId()){
            case R.id.tv_start:
                countDown=10;
                startTask(MsgWhat.MSG_PREPARE_TIME);
                break;
            case R.id.tv_stop:
                countDown=0;
                stopMsg();
                break;
            case R.id.tv_pause:
                startTask(MsgWhat.MSG_STOP_TIME);
                break;
            case R.id.tv_restart:
                startTask(MsgWhat.MSG_PREPARE_TIME);
                break;
        }
    }
    public void startTask(int flag){
        if (mCountdownTask!=null){
            mCountdownTask.cancel();
        }
        if (timer==null){
            timer=new Timer();
        }
        mCountdownTask = new EmptyMessageTask(myHandler, flag);
        timer.schedule(mCountdownTask, 1000, 1000);
    }
    public void stopMsg(){
        if (timer != null) {
            timer.cancel();
            timer=null;
        }
        if (mCountdownTask != null) {
            mCountdownTask.cancel();
            mCountdownTask=null;
        }
    }
    private  class MyHandler extends Handler {
        private WeakReference<MainActivity> activityWeakReference ;
        public MyHandler(MainActivity activity) {
            activityWeakReference = new WeakReference<MainActivity>(activity) ;
        }
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg) ;
            MainActivity activity = activityWeakReference.get() ;
            if (activity == null) {
               return;
            }
            switch (msg.what){
                case MsgWhat.MSG_PREPARE_TIME:
                    if (countDown>0){
                        countDown--;
                    }
                    tv_num.setText(""+countDown);
                    break;
                default:
                    break;
            }
        }
    }
    @Override
    protected void onDestroy() {
        super.onDestroy();
        myHandler.removeCallbacksAndMessages(null);
    }
}