无法在android中恢复我的线程

Question

我知道这里有很多关于此主题的问题和答案，但我无法解决以下问题以在我的应用中恢复线程。

这是我的可运行文件：-

Runnable ViewPagerVisibleScroll= new Runnable() {
    @Override
    public void run() {
                if (i <= mAdapter.getCount() - 1) {
                    verticalViewPager.setCurrentItem(i, true);
                    handler.postDelayed(ViewPagerVisibleScroll, 3000);

                    i++;
                    while (isPaused) {
                        synchronized (ViewPagerVisibleScroll) {
                            // wait for resume() to be called
                            try {
                                ViewPagerVisibleScroll.wait();
                                //  isPaused = false;
                            } catch (InterruptedException e) {
                                // TODO Auto-generated catch block
                                e.printStackTrace();
                            }

                        }
                    }
                }
    }
};

暂停和恢复方法：-

public void pause() {
    synchronized (ViewPagerVisibleScroll) {
        isPaused = true;
    }
}

public synchronized void resume() {
    synchronized (ViewPagerVisibleScroll) {
        isPaused = false;
        // notify anybody waiting on "this"
        ViewPagerVisibleScroll.notify();
    }
}

我的问题是当我调用 pause 方法时线程将 pause() 但当我调用 resume() 时它不会恢复。请帮我解决这个问题。

Answer 1

首先，我看到了这段代码：

public void pause() {
    synchronized (ViewPagerVisibleScroll) {
        isPaused = true;   //!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
    }
}

public synchronized void resume() {
    synchronized (ViewPagerVisibleScroll) {
        isPaused = false;
        // notify anybody waiting on "this"
        ViewPagerVisibleScroll.notify();
    }
}

还有这个：

while (isPaused)

我可以保证，如果您调用方法pause()，即您将isPaused 设置为true，那么当isPaused 为真时，此循环将被执行。你应该使用!isPaused:

while (!isPaused)

即不暂停做某事。这只是一个介绍。

所以，回到你的问题，我建议你下一步：
1）。创建static final对象进行同步：

private static final Object syncObj = new Object();
private static final Object stopSyncObj = new Object();

2)。将您的可运行文件实现为内部类：

public class MyRunnable implements Runnable {

        private boolean isPaused;
        private boolean isStopped;

        public MyRunnable(){
            synchronized (stopSyncObj){
                isStopped = false;
            }
            synchronized (syncObj){
                isPaused = false;
            }
        }

        @Override
        public void run() {
            if (i <= mAdapter.getCount() - 1) {
                verticalViewPager.setCurrentItem(i, true);
                handler.postDelayed(ViewPagerVisibleScroll, 3000);

                i++;

                //Check thread
                boolean isStopped = false;

                while (!isStopped) {
                    synchronized (syncObj) {
                        boolean isPaused = false;
                        synchronized (syncObj){
                            isPaused = this.isPaused;
                        }

                        if(isPaused) {
                            // wait for resume() to be called
                            try {
                                syncObj.wait();
                                //  isPaused = false;
                            } catch (InterruptedException e) {
                                // TODO Auto-generated catch block
                                e.printStackTrace();
                            }
                        }else{
                            //do somethinghere

                        }
                    }

                    //Check 'stop' flag
                    synchronized (stopSyncObj){
                        isStopped = this.isStopped;
                    }
                }
            }
        }

        //This method stops runnable forever
        public void stopRunnable(){
            synchronized (stopSyncObj){
                isStopped = true;
            }
        }

        public void pause(){
            synchronized (syncObj){
                isPaused = true;
            }
        }

        public void resume(){
            synchronized (syncObj){
                isPaused = false;
                syncObj.notifyAll();
            }
        }
    }

3)。使用它：

Runnable ViewPagerVisibleScroll = new MyRunnable();

更新答案
对于自动滚动使用ScheduledThreadPoolExecutor:

ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(1);
        executor.schedule(new Runnable() {
            @Override
            public void run() {
                //scroll viewpager
            }
        }, 3, TimeUnit.SECONDS);

要阻止它使用：

executor.shutdown();