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线程只运行一次-Java-Android

bluetooth multithreading android java

Seraphiim · 技术社区 · 8 年前

所以我在做一个项目。我有一个Arduino机器人,可以通过蓝牙与应用程序通信。从本质上讲,Arduino是一种配备各种传感器的战斗机器人。当机器人识别出它被射杀时(通过红外代码)。它会向应用程序发送一条消息,以降低其运行状况。(Arduino发送小写字母“h”,用“#”作为分隔符,以表示消息结束。现在,我正试图运行一个线程来侦听数据,当应用程序上接收到字符(“h”)或任何其他字符时,就会对其进行处理,并调用适当的函数。现在我的问题是我的函数只能调用一次。我对线程是新手,很难理解为什么它不恢复线程并继续收听更多字符。

这是侦听数据的线程。这有点混乱,因为我有一些跟踪代码来试图找到问题

void beginListenForData(){
    final Handler handler = new Handler();
    final Handler handler2 = new Handler();
    final byte delimiter = 35; //ASCII for #
    stopWorker = false;
    readBufferPosition = 0;
    readBuffer = new byte[1024];
    workerThread = new Thread(new Runnable(){

        public void run(){

            while(!Thread.currentThread().isInterrupted() && !stopWorker){

                try{
                    int bytesAvailable = mmInputStream.available();
                    //InputStream mmInputStream = btSocket.getInputStream();
                    //inTest.setText("INPUT: " + bytesAvailable);
                    if(bytesAvailable>0){
                        //inTest.setText("Bytes Available");
                        byte[] packetBytes = new byte[bytesAvailable];
                        mmInputStream.read(packetBytes);
                        for(int i=0;i<bytesAvailable;i++)
                        {
                            byte b = packetBytes[i];
                            if(b == delimiter)
                            {
                                byte[] encodedBytes = new byte[readBufferPosition];
                                System.arraycopy(readBuffer, 0, encodedBytes, 0, encodedBytes.length);
                                final String data = new String(encodedBytes, "US-ASCII");

                                readBufferPosition = 0;

                                handler.post(new Runnable()
                                {

                                    public void run()
                                    {
                                        /*
                                        Possible messages from arduino
                                            r = arduino ready
                                            k = Robot has tilted and is dead
                                            h = robot has been shot
                                        */


                                        inTest.setText("Received: " + data + "\n" +"Times shot: " + timesShot);

                                        if(data.equals("h")){
                                            //workerThread.interrupt();

                                            System.out.println("ROBOT HAS BEEN SHOT");
                                            robo1.takeDamage(10);
                                            System.out.println("ROBOT HAS CALLED DAMAGE METHOD");
                                        }

                                        //if(data.equals("k")){
                                        //  msg("ROBOT FLIPPED!");
                                        //}


                                    }

                                });
                            }
                            else
                            {
                                readBuffer[readBufferPosition++] = b;
                            }
                        }
                    }
                }
                catch (IOException ex)
                {
                    msg("IEXCEPTION TRIGGER");
                    stopWorker = true;
                }
            }
        }
    });
    msg("WorkerThread Start");
    workerThread.start();
}

这里还有我的takeDamage方法,其中也有一些跟踪代码,并显示了我试图解决这个问题的一些事情。

       private void takeDamage(int dmg){
        ROBOT_HEALTH -= dmg;
        msg("Robot Shot");
        timesShot++;
        System.out.println("ROBOT IS TAKING DAMAGE");
        inTest.setText("Times shot: " + timesShot + "\n Robot Health: " +  ROBOT_HEALTH);

        //workerThread.start();
        //msg("Robot Health" + robo1.getHealth() + "\n");
        //if(this.getHealth() <= 0){
         //   //GAME OVER ROBOT DEAD
          //  Toast.makeText(getApplicationContext(), "ROBOT DEAD",
          //          Toast.LENGTH_LONG).show();
        //}
    }

太长,读不下去了为什么线程在方法调用后不继续侦听数据。如果没有调用方法,则处理程序将无限期地保持循环。

1 回复 | 直到 8 年前

Peppermint Paddy 8 年前

我没有真正尝试过这个代码,但我认为你明白了。具有 start() 你从线程开始 stop() 你打断了它。这个 Runnable 实现可能永远运行的while循环;)但我想你总有一天会阻止的。希望这有帮助!

private Thread thread;    

public void start() {
    if (thread != null) return;
    thread = new Thread(new ListenerRunnable());
    thread.start();
}

public void stop() {
    if (thread == null) return;
    thread.interrupt();
    thread = null;
}

private static class ListenerRunnable implements Runnable {

    @Override
    public void run() {
        while (true) {
            try {

                // !!! Here goes your code to listen !!!

            } catch (final InterruptedException e) {
                if (Thread.currentThread().isInterrupted()) {
                    break;
                }
            }
        }
    }
}