如何在 Android 中暂停/恢复线程? [英] How to pause/resume thread in Android?

问题描述

我有一个线程运行到一个活动中.我不希望线程在用户单击主页按钮时继续运行，或者，例如，用户接到电话.所以我想暂停线程并在用户重新打开应用程序时恢复它.我试过这个:

I have a thread that running into an activity. I don't want that the thread continuos running when the user click the home button or, for example, the user receive a call phone. So I want pause the thread and resume it when the user re-opens the application. I've tried with this:

protected void onPause() {
  synchronized (thread) {
    try {
      thread.wait();
    } catch (InterruptedException e) {
      e.printStackTrace();
    }
  }
  super.onPause();
}
protected void onResume() {
  thread.notify();
  super.onResume();
}

它停止了线程但不恢复它，线程似乎被冻结了.

It stops the thread but don't resume it, the thread seems freezed.

我也尝试过使用已弃用的方法 Thread.suspend() 和 Thread.resume()，但在本例中使用了 Activity.onPause() 线程不会停止.

I've also tried with the deprecated method Thread.suspend() and Thread.resume(), but in this case into Activity.onPause() the thread doesn't stop.

有人知道解决办法吗?

推荐答案

正确使用 wait() 和 notifyAll() 使用锁.

Use wait() and notifyAll() properly using a lock.

示例代码:

class YourRunnable implements Runnable {
    private Object mPauseLock;
    private boolean mPaused;
    private boolean mFinished;

    public YourRunnable() {
        mPauseLock = new Object();
        mPaused = false;
        mFinished = false;
    }

    public void run() {
        while (!mFinished) {
            // Do stuff.

            synchronized (mPauseLock) {
                while (mPaused) {
                    try {
                        mPauseLock.wait();
                    } catch (InterruptedException e) {
                    }
                }
            }
        }
    }

    /**
     * Call this on pause.
     */
    public void onPause() {
        synchronized (mPauseLock) {
            mPaused = true;
        }
    }

    /**
     * Call this on resume.
     */
    public void onResume() {
        synchronized (mPauseLock) {
            mPaused = false;
            mPauseLock.notifyAll();
        }
    }

}

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