Question

我有一个简单的问题：

我有一个名为rlMF的线程。我这样创造了它：

public Thread rlMF = new Thread(new Runnable() {
    public void run() {
        reloadMissingFiles();
        stopTh();
    }

    public void stopTh() {
        activityStopped = true;
    }
});

现在我想从外部线程调用stopTh函数。为什么我不能简单地调用rlMF.stopTh（）;我还能做什么呢？

示例：

protected void onPause() {
    Log.d("Info", "destroying...");
    activityStopped = true;
    rlMF.stopTh();
    super.onPause();
}

不工作......

Answer 1

因为可访问的界面来自Thread。为了让您可以从out访问方法，您需要指定一个公开此方法的类型。

如果你仔细看一下这个方法是在Runnable的实例中实现的。甚至不在Thread。

如果你真的需要访问Runnable对象，你可能会有这样的事情：

class MyRunnable implements Runnable {
    public void run() {
    ...
    }

    public void fooBar() {
    ...
    }       
}

public void someMethod() {
    MyRunnable myRunnable = new MyRunnable();
    Thread thread = new Thread(myRunnable);
    ...
    myRunnable.fooBar();
    ...
}

Answer 2

弗朗西斯科方法的一个例子，除了你想要实现的目标。也许这可以指出你正确的方向

public class CustomRun implements Runnable {
    public void run() {
        reloadMissingFiles();
        stopTh();
    }

    public void stopTh() {
        activityStopped = true;
    }
}

在您的代码中

// start thread with custom runner
CustomRun runner = new CustomRun();
new Thread(runner).start();

// call your stopTh method on CustomRun class
protected void onPause() {
    Log.d("Info", "destroying...");
    activityStopped = true;
    runner.stopTh();
    super.onPause();
}

Answer 3

您的目标是从onPause中断线程。有几种方法可以做到这一点，但实际上，您需要在reloadMissingFiles中包含一些可中断性。

选项1

您可以使用类似的布尔标志 - 您需要将其声明为volatile以确保更改在线程中可见：

private volatile boolean activityStopped = false;

public void reloadMissingFiles() {
    while (!activityStopped) {
       //load small chunks so that the activityStopped flag is checked regularly
    }
}

public Thread rlMF = new Thread(new Runnable() {
    public void run() {
        reloadMissingFiles(); //will exit soon after activityStopped has been set to false
    }
});

protected void onPause() {
    //This will stop the thread fairly soon if the while loop in
    //reloadMissingFiles is fast enough
    activityStopped = true;
    super.onPause();
}

选项2（更好的方法）

我不知道你在reloadMissingFiles做了什么，但我想这是某种I / O操作，通常是可以中断的。然后，您可以制定中断策略，一旦捕获到InterruptedException，就会停止：

public void reloadMissingFiles() {
    try {
        //use I/O methods that can be interrupted
    } catch (InterruptedException e) {
        //cleanup specific stuff (for example undo the operation you started
        //if you don't have time to complete it
        //then let the finally block clean the mess
    } finally {
        //cleanup (close the files, database connection or whatever needs to be cleaned
    }
}

public Thread rlMF = new Thread(new Runnable() {
    public void run() {
        reloadMissingFiles(); //will exit when interrupted
    }
});

protected void onPause() {
    runner.interrupt(); //sends an interruption signal to the I/O operations
    super.onPause();
}

注意：您还可以阅读this article以获取更深入的版本。

线程中的自定义函数

3 个答案: