java - 暂停计时器然后继续

Question

这个问题已经有答案了:

Pausing/stopping and starting/resuming Java TimerTask continuously? (8 个回答)

已关闭 9 个月前。

请参阅@Yuri 从此处发布的代码。 How to stop a timer after certain number of times 。如果我想因为某种情况停止它然后再次重新启动它。我该如何去做呢？

    private final static int DELAY = 10000;
    private final Handler handler = new Handler();
    private final Timer timer = new Timer();
    private final TimerTask task = new TimerTask() {
        private int counter = 0;
        public void run() {
            handler.post(new Runnable() {
                public void run() {
                    Toast.makeText(MainActivity.this, "test", Toast.LENGTH_SHORT).show();
                }
            });
            if(++counter == 4) {
                timer.cancel();
            }

    //do some stuff in my app
   //restart the timer again

        }
    };

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        timer.schedule(task, DELAY, DELAY);

    }

这是我尝试过的方法，但它总是让我崩溃。

    final int DELAY = 10000;
        Timer timer;
        MyTask task;
        startManager Scanner;
        Handler handler;



        public class MyTask extends TimerTask {

            @Override
            public void run() {
                handler.post(new Runnable() {
                    public void run() {
                        //do Stuff here
                        }
        });
    }
        public class startManager {

            public startManager() {
                handler = new Handler();
                timer = new Timer();
            }

            public void start() {

                timer.schedule(task, 0, DELAY);
            }

            public void cancel() {

                timer.cancel();
                timer.purge();

            }
        }

    }

 @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);

Scanner = new startManager();
//do some stuff
 if (...)
Scanner.cancel()
//restart the timer and its task
Scanner=new startManager();
        }

Answer 1

弄清楚了，是因为我没有在startManager()中初始化任务