Android的蓝牙发送消息的工作只有一次 [英] Android bluetooth send message working first time only

问题描述

我需要从树莓PI串发送消息到Android设备。我只得到消息第一次。之后，它不在所有工作。我使用的树莓PI PYTHON code。后第一次，这是无法搜索蓝牙设备，它正在运行的UUID。不过，如果我重新启动Android应用 - 再正常工作的第一次。我使用AcceptThread的建议这里。我没有用ConnectThread或ConnectedThread在我的应用程序，因为我只需要进入的消息。我是否需要关闭一些关于暂停或销毁。或者，做我需要做的是不要在网页中提到的东西吗？

I need to send string message from Raspberry PI to Android device. I am getting message first time only. After that it does not work at all. I am using PYTHON code in Raspberry PI. After first time, it is unable to search for a bluetooth device, which is running that UUID. However, if I restart Android application - again it works fine for first time. I am using AcceptThread as suggested here. I have not used ConnectThread or ConnectedThread in my application, as I need only incoming messages. Do I need to close something on Pause or Destroy. Or, do I need to do something which is not mentioned in that page?

下面是code：

private UUID MY_UUID = UUID.fromString("1e0ca4ea-299d-4335-93eb-27fcfe7fa848");
private AcceptThread acceptThread;

private class AcceptThread extends Thread {
    private final BluetoothServerSocket mmServerSocket;

    public AcceptThread() {
        // Use a temporary object that is later assigned to mmServerSocket,
        // because mmServerSocket is final
        BluetoothServerSocket tmp = null;
        try {
            // MY_UUID is the app's UUID string, also used by the client code
            tmp = bluetoothAdapter.listenUsingRfcommWithServiceRecord(TAG, MY_UUID);
        } catch (IOException e) { }
        mmServerSocket = tmp;
    }

    public void run() {
        BluetoothSocket socket = null;
        // Keep listening until exception occurs or a socket is returned
        while (true) {
            try {
                socket = mmServerSocket.accept();
            } catch (IOException e) {
                break;
            }
            // If a connection was accepted
            if (socket != null) {
                // Do work to manage the connection (in a separate thread)
                manageConnectedSocket(socket);
                try {
                    mmServerSocket.close();
                }
                catch(IOException e){

                }
                break;
            }
        }
    }

    /** Will cancel the listening socket, and cause the thread to finish */
    public void cancel() {
        try {
            mmServerSocket.close();
        } catch (IOException e) { }
    }
}

我不使用PI信息，只需登录一个字符串。如上所述，它工作第一时间：

I am not using PI message, just logging a string. As mentioned above, it works first time:

private void manageConnectedSocket(BluetoothSocket socket) {
    Log.i(TAG, "Hurray!! I am here");
    //acceptThread.cancel();
}

下面是树莓PI蟒蛇code：

Here is the PYTHON code in Raspberry PI:

import sys
import bluetooth

uuid = "1e0ca4ea-299d-4335-93eb-27fcfe7fa848"

service_matches = bluetooth.find_service( uuid = uuid )

if len(service_matches) == 0:
  print "couldn't find the BluetoothWithPi service"
  sys.exit(0)

first_match = service_matches[0]
port = first_match["port"]
name = first_match["name"]
host = first_match["host"]

print "connected to \"%s\" on %s" % (name, host)

sock=bluetooth.BluetoothSocket( bluetooth.RFCOMM )
sock.connect((host, port))
sock.send("Hello from Raspberry PI!!")
sock.close()

它显示已连接到......的消息第一次。第二次它显示找不到......消息。

First time it displays 'Connected to ...' message. Second time it displays 'Couldn't find...' message.

推荐答案

我们只需要添加一些code到 manageConnectedSocket 块。基本上，我们需要取消acceptThread如果不为空，然后重新启动该服务：

We just need to add some code into manageConnectedSocket block. Basically we need to cancel the acceptThread if not null and restart the service:

private void manageConnectedSocket(BluetoothSocket socket) {
    Log.i(TAG, "Hurray!! I am here");
    //
    if (acceptThread != null) {
        acceptThread.cancel();
        acceptThread = null;
    }
    //
    if (acceptThread == null) {
        acceptThread = new AcceptThread();
        acceptThread.start();
    }
}

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