Android开发Sleep与Message并用无效解决方案

问题描述

2022/8/24 21：54特此记录，历经两天解决此问题
为了完成比赛题目要求，我在代码中写了当读取到已登记epc会触发电动推杆缩回，等完全缩回再过10秒伸出，这一步骤是合理运行的，但是因要更新界面UI，而当前在子线程，故采用Handler-Message的方式发送消息，当UI主线程接收到消息时更新界面
为了省事，我将此操作写在了同一作用域Thread.sleep前后，当代码执行到这里的时候并没有达到预期的效果，事时是Message等sleep执行完后一起触发了，所以得出结论Message不能在同一作用域用两次，如果用的话不会报错，只是效果会得不尝失

原代码

public void RfidCtrl(){
    new Thread(new Runnable() {
        @Override
        public void run() {
            while (true){
                try {
                    Thread.sleep(5000);
                    rfid.readSingleEpc(new SingleEpcListener() {
                        @Override
                        public void onVal(String s) {
                            try {
                                Log.e("RfidEPC", s);
                                tempEpcInfo = s;
                                if(!currentEpcInfo.equals(tempEpcInfo)){
                                    if(!tempEpcInfo.equals(rfidEpcInfo)) {
                                        textToSpeech.speak("信息未登记", TextToSpeech.QUEUE_ADD, null);
                                        Message msg = new Message();
                                        msg.what = 0;
                                        handler.sendMessage(msg);
                                    }
                                    else{
                                        textToSpeech.speak("你好，请通过", TextToSpeech.QUEUE_ADD, null);
                                        Message msg = new Message();
                                        msg.what = 1;
                                        handler.sendMessage(msg);
                                        modbus4150.ctrlRelay(1, true, null);
                                        modbus4150.ctrlRelay(0, false, null);
                                        modbus4150.ctrlRelay(2, false, null);

                                        modbus4150.ctrlRelay(5, false, null);
                                        modbus4150.ctrlRelay(6, true, null);

                                        Log.e("Thread", Thread.currentThread().getName());
                                        Thread.sleep(17000);
                                        /*for(int i = 0; i < 17000; i++){
                                            Thread.sleep(1);
                                        }*/
                                        Log.e("Thread2", Thread.currentThread().getName());
                                        modbus4150.ctrlRelay(5, true, null);
                                        modbus4150.ctrlRelay(6, false, null);

                                        modbus4150.ctrlRelay(1, false, null);
                                        modbus4150.ctrlRelay(0, true, null);
                                        modbus4150.ctrlRelay(2, false, null);

                                        Message msg_2 = new Message();
                                        msg_2.what = 0;
                                        handler.sendMessage(msg_2);
                                    }
                                    currentEpcInfo = tempEpcInfo;
                                }
                            }
                            catch (Exception e){
                            }
                        }

                        @Override
                        public void onFail(Exception e) {

                        }
                    });
                } catch (Exception e) {
                    e.printStackTrace();
                }

            }
        }
    }).start();
}

更改后

public void RfidCtrl(){
  new Thread(new Runnable() {
      @Override
      public void run() {
          while (true){
              try {
                  if(isTurn) {
                      Thread.sleep(17000);
                      modbus4150.ctrlRelay(5, true, null);
                      modbus4150.ctrlRelay(6, false, null);

                      modbus4150.ctrlRelay(1, false, null);
                      modbus4150.ctrlRelay(0, true, null);
                      modbus4150.ctrlRelay(2, false, null);

                      Message msg_2 = new Message();
                      msg_2.what = 0;
                      handler.sendMessage(msg_2);
                      isTurn = false;
                      currentEpcInfo = "null";
                  }
                  else Thread.sleep(3000);
                  rfid.readSingleEpc(new SingleEpcListener() {
                      @Override
                      public void onVal(String s) {
                          try {
                              Log.e("RfidEPC", s);
                              tempEpcInfo = s;
                              if(!currentEpcInfo.equals(tempEpcInfo)){
                                  if(!tempEpcInfo.equals(rfidEpcInfo)) {
                                      textToSpeech.speak("信息未登记", TextToSpeech.QUEUE_ADD, null);
                                      Message msg = new Message();
                                      msg.what = 0;
                                      handler.sendMessage(msg);
                                  }
                                  else{
                                      textToSpeech.speak("你好，请通过", TextToSpeech.QUEUE_ADD, null);
                                      Message msg = new Message();
                                      msg.what = 1;
                                      handler.sendMessage(msg);
                                      modbus4150.ctrlRelay(1, true, null);
                                      modbus4150.ctrlRelay(0, false, null);
                                      modbus4150.ctrlRelay(2, false, null);

                                      modbus4150.ctrlRelay(5, false, null);
                                      modbus4150.ctrlRelay(6, true, null);

                                      Log.e("Thread", Thread.currentThread().getName());
                                      //Thread.sleep(17000);
                                      Log.e("Thread2", Thread.currentThread().getName());
                                      isTurn = true;
                                  }
                                  currentEpcInfo = tempEpcInfo;
                              }
                          }
                          catch (Exception e){
                          }
                      }

                      @Override
                      public void onFail(Exception e) {

                      }
                  });
              } catch (Exception e) {
                  e.printStackTrace();
              }

          }
      }
  }).start();
}

Handler消息处理模块

handler = new Handler(message -> {
     switch (message.what){
         case 0:
             Toast.makeText(MainActivity.this, "Close", Toast.LENGTH_SHORT).show();
             m_raycast.setImageResource(R.drawable.pic_traffic_light_red);
             gate.setImageResource(R.drawable.pic_parking_rod_closed);
             break;
         case 1:
             Toast.makeText(MainActivity.this, "Turn", Toast.LENGTH_SHORT).show();
             m_raycast.setImageResource(R.drawable.pic_traffic_light_green);
             gate.setImageResource(R.drawable.pic_parking_rod_open);      //修改UI界面控件属性
             break;
     }
     return true;
 });

发送消息模块

   Message msg = new Message();
   msg.what = 0;
   handler.sendMessage(msg);