java - 未调用 handleMessage 函数

Question

我正在帮助我的 friend 开发一个 Android 应用程序，我不明白为什么我无法获取 Handle 函数，handleMessage() 被调用。我目前正在尝试通过蓝牙进行通信，我有一个处理写入的线程和一个处理读取的线程，所以我想我在某个地方搞砸了。我真的不熟悉 Thread，我想知道是否有人能发现我的错误!我知道写入功能正在工作，因为我看到蓝牙芯片在写入"$$$"下面的代码后进入命令模式。

主要 Activity :

public class MainActivity extends Activity{
....
    private final Handler mHandler = new Handler(){
            @Override
        public void handleMessage(Message msg) {
            System.out.println("in mHandler");//NOT CALLED
                switch (msg.what) {
                    case (MESSAGE_READING):
                    byte[] readBuf = (byte[])msg.obj;
                    String readMessage = new String(readBuf,0,msg.arg1);
                    System.out.println("READ: " + readMessage);
                    break;
                default:
                        System.out.println("default!");
                    break;
                }
            }
        };
        ...
     }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        ...
        mConnectThread = new ConnectThread(device, mHandler);
        mConnectThread.run();
        ListenerThread mListener = new ListenerThread(mConnectThread,mHandler);
        mListener.run();
    }

连接线程:

public class ConnectThread{

public final BluetoothSocket mmSocket;
public final BluetoothDevice mmDevice;
private final Handler mHandler;
public static ConnectedThread mConnectedThread;

public ConnectThread(BluetoothDevice device, Handler mHandler) {
    // Use a temporary object that is later assigned to mmSocket,
    // because mmSocket is final
    BluetoothSocket bs = null;
    mmDevice = device;

    // Get a BluetoothSocket to connect with the given BluetoothDevice
    try {
        // MY_UUID is the app's UUID string, also used by the server code
        UUID uuid = UUID.fromString("00001101-0000-1000-8000-00805f9b34fb"); //Standard Serial Port Service ID
        bs = device.createRfcommSocketToServiceRecord(uuid);
    } catch (IOException e) {
        System.err.println("IOException in ConnectThread");
    }

    this.mHandler = mHandler;
    mmSocket = bs;
}

public void run() {
    //TODO Cancel discovery because it will slow down the connection

    try {
        // Connect the device through the socket. This will block
        // until it succeeds or throws an exception
        mmSocket.connect();
    } catch (IOException connectException) {
        // Unable to connect; close the socket and get out
        try {
            mmSocket.close();
        } catch (IOException closeException) { }
        return;
    }

    // Do work to manage the connection (in a separate thread)
    mConnectedThread = new ConnectedThread(mmSocket, mHandler);
    mConnectedThread.run();

}
...
}

连接线程:

public class ConnectedThread extends Thread {
....
public void manageConnectedSocket() {

    byte[] buffer = new byte[1024];  // buffer store for the stream
    int bytes; // bytes returned from read()

    // Keep listening to the InputStream until an exception occurs
    while (true) {
        try {
            // Read from the InputStream
            bytes = mmInStream.read(buffer);
            System.out.println("Reading bytes.");
            status = MESSAGE_READING;
            // Send the obtained bytes to the UI activity
            Message msg = Message.obtain(mHandler, MESSAGE_READING, bytes, -1, buffer);
            mHandler.sendMessage(msg);
        } catch (IOException e) {
            System.err.println("Error reading input");
            break;
        }
        status = READY;
    }
}
...
}

监听线程:

public class ListenerThread extends Thread {

...

public final BluetoothSocket mmSocket;
private final Handler mHandler;
private final ConnectedThread mConnectedThread;

public ListenerThread(ConnectThread mConnectThread, Handler mHandler){
    this.mHandler = mHandler;
    mmSocket = mConnectThread.mmSocket;
    this.mConnectedThread = mConnectThread.getConnectedThread();
}

public void run(){
    while (true){
        if (getStatus() == READY){
            write("$$$".getBytes());
            break;
        }
    }
}
...
}

我查看了一些关于 handleMessage 的其他问题，但没有帮助。有什么想法吗？

编辑:刚刚意识到这是很多代码。基本上我将 mHandler 传递给我的不同线程，我认为这是发生了一些不好的事情的地方。我有 ConnectThread、ConnectedThread 和 ListenerThread。我正在查看蓝牙的 Android 文档说它在后台运行，因为一些调用(write,read,device.connect()) 正在阻塞调用。

Answer 1

我认为您的代码存在问题，您是通过 run() 方法启动线程，这意味着您只是在一个对象上执行 run() 方法.但是您必须调用 start() 方法，这将启动一个新线程并自动调用您的 run() 方法。

这里引用自 Thread.start() 方法文档

Causes this thread to begin execution; the Java Virtual Machine calls the run method of this thread.