java - postDelayed() 与 Android 消息

Question

我希望我的主 UI 线程在向工作线程发送空消息以执行某些操作之前有效地“ sleep ”1 秒。

Sleep() 对我来说是一个问题，因为在执行 sleep() 时我无法正确 quit() 线程，所以我想将其更改为 postDelayed(runnable r, long msDelay) 但它需要 runnable 对象，而不是 Message。我如何更改此代码？我只是将空消息从主 UI 线程传递到工作线程。

用户界面线程:

public class MainActivity extends Activity
{
    static Worker w1, w2;

 static Handler mainUIHandler = new Handler()
    {

        @Override
        public void handleMessage(Message msg)
        {
            String sender = msg.getData().getString("SENDER");

            if (Objects.equals(sender, "CPU1")) 
            {
                mInfoTextView.setText("worker 1 thinking...");

                  //how to change the following 2 lines to postDelayed()?
                try{
                     Thread.sleep(1000);
                   } catch (Exception ignored) { }

                 w2.handler.sendMessage(w2.handler.obtainMessage());

            }
        }
    };
...
}

和工作线程

 class Worker extends HandlerThread
    {
      ...

        Worker(String name)
        {
            super(name);
        }


        Handler handler= new Handler()
        {
            @Override
            public void handleMessage(Message msg)
            {
                //perform work
                     Foo work = dowork();
               //communicate work to the UI thread to update the display
                Message message = MainActivity.mainUIHandler.obtainMessage();

                Bundle bundle = new Bundle();
                bundle.putString("NAME", name);
                bundle.putInt("work", work);

                message.setData(bundle);

                MainActivity.mainUIHandler.sendMessage(message);
            }
        };

        @Override
        public void run()
        {
            this.setName(WorkerThread.class.getName());
            this.setPriority(android.os.Process.THREAD_PRIORITY_BACKGROUND);
        }
    }

我尝试创建一个新的 Runnable() 并将其传递给 postDelayed():

  w2.handler.postDelayed(new Runnable()
                    {

                        @Override
                        public void run()
                        {
                            System.out.println("hello");
                        }
                    }, 1000);

但它没有触发 w2 中的处理程序

Answer 1

您可以使用 Handler.sendMessageDelayed() 延迟消息 :

public class MainActivity extends Activity {

    // ...

    static Handler mainUIHandler = new Handler() {

        @Override
        public void handleMessage(Message msg) {

            // ...

            w2.handler.sendMessageDelayed(w2.handler.obtainMessage(), 1000);
        }
    }
}