Question

我试图在Android中实现可以在自己的线程中工作的对象（我不想让处理程序公开，我想用自己的公共api包装sentMessage方法）。它有公共方法将数据传递给对象。此对象与活动生命周期（onResume，onPause）相关联。我想使用looper和handler，而不仅仅是带有无限循环的纯Java线程。我想在恢复时启动工作线程并停止处理暂停回调。对象必须无限地等待新消息。这是我的代码：

public class ThreadingObject {

    private MyThread thread;

    public ThreadingObject() {}

    public void onResume() {
        thread = new MyThread();
        thread.startWorking();
    }

    public void onPause() {
        thread.stopWorking();
    }

    public void setMessage(Object object) {
        Message msg = new Message();
        msg.obj = object;
        thread.handler.sendMessage(msg);
    }

    protected void work(Object object) {
        //Do something with object in own thread
    }

    private class MyThread extends Thread {
        public Handler handler;

        @Override
        public void run() {
            Looper.prepare();
            handler = new Handler() {

                @Override
                public void handleMessage(Message msg) {
                    ThreadingObject.this.work((String[]) msg.obj);
                }
            };
            Looper.loop();
        }

        public void startWorking() {
            start();
        }

        public void stopWorking() {
            handler.getLooper().quit();
        }
    }
}

这是正确的实施吗？我收到警告：“在死线程上向处理程序发送消息”。有没有我没看到的问题？

Answer 1

这是我的实施：

public class ThreadingObject {

    private HandlerThread thread;
    private Handler handler;

    private Handler.Callback handlerCallback = new Handler.Callback() {
        @Override
        public boolean handleMessage(Message msg) {
            work(msg.obj);
            return true;
        }
    };

    public ThreadingObject() {}

    public void onResume() {
        thread = new HandlerThread("SurfaceView HandlerThread");
        thread.start();
        handler = new Handler(thread.getLooper(), handlerCallback);
    }

    public void onPause() {
        if(thread != null) {
            thread.quit();
            thread = null;
        }
        handler = null;
    }

    public void setMessage(Object object) {
        Message msg = new Message();
        msg.obj = object;
        handler.sendMessage(msg);
    }

    protected void work(Object obj) {
        //Working
    }
}

Answer 2

在run（）方法中，如果你需要重新运行或使用循环，你需要自己添加它，例如。

并且您的错误发生是因为您尝试调用已完成的线程。

    boolean aLoopLoopLoop = true;
    Handler handler;

    // this handler, you no need to declare it repeatedly, just declare it in onCreate() is enough
    handler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            ThreadingObject.this.work((String[]) msg.obj);
        }
    };

    // -----
    @Override
    public void run() {
        Looper.prepare();
        final Looper looper = Looper.myLooper();
        while(aLoopLoopLoop) {
            // write your code here
            Looper.loop();
        }
        // after loop exit, quit loop
        handler.postDelayed(new Runnable() {
            @Override
            public void run() {
                looper.quit(); 
            }
        }, 3000);
    }

    // -----
    public void stopWorking() {
        aLoopLoopLoop = false;
    }

使用looper自带线程的Android Java对象

2 个答案: