Question

这是来自Google示例代码BluetoothChat的标准代码。 BluetoothChatService.java

public void run() {
        Log.i(TAG, "BEGIN mConnectedThread");
        byte[] buffer = new byte[1024];
        int bytes;

        // Keep listening to the InputStream while connected
        while (mState == STATE_CONNECTED) {
            try {
                // Read from the InputStream
                bytes = mmInStream.read(buffer);
                // Send the obtained bytes to the UI Activity
                mHandler.obtainMessage(Constants.MESSAGE_READ, bytes, -1, buffer)
                        .sendToTarget();
            } catch (IOException e) {
                Log.e(TAG, "disconnected", e);
                connectionLost();
                break;
            }
        }
    }

我尝试使用

连接设备时

mChatService.connect(device, false);

我得到以下异常

java.io.IOException: bt socket closed, read return: -1
at android.bluetooth.BluetoothSocket.read(BluetoothSocket.java:872)
at android.bluetooth.BluetoothInputStream.read(BluetoothInputStream.java:96)
at java.io.InputStream.read(InputStream.java:163)

任何帮助都将不胜感激。

Answer 1

您是否在Android清单中包含了针对您的应用的蓝牙权限？

<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />

Answer 2

我猜问题是mmSocket.connect()

尝试通过反映获取方法createRfcommSocket。

以下是基于Google示例代码BluetoothChat的示例。

            // Make a connection to the BluetoothSocket
            try {
                Thread.sleep(500);
                // This is a blocking call and will only return on a
                // successful connection or an exception
                mmSocket.connect();
                OutputStream os = mmSocket.getOutputStream();
                // Here: connect success
            } catch (Exception e) {
                Log.i(TAG, "Lost 1st try; SPP connect[2]");
                try {
                    mmSocket.close();// close the current socket
                    mmSocket = null;
                    Thread.sleep(500L); // wait for a while
                    mmSocket = (BluetoothSocket) mmDevice.getClass().getMethod("createRfcommSocket", new Class[]{int.class}).invoke(mmDevice, 1); // The key method !
                    mmSocket.connect();
                    OutputStream os = mmSocket.getOutputStream();
                    // Here: connect success
                    synchronized (ESDevice.this) {
                        mSPPConnectThread = null;
                    }
                    connected(mmSocket, mmDevice); // begin connected thread
                } catch (Exception e2) {
                    Log.e(TAG, "Lost 2nd try. Connect fail", e2);
                    connectionFailed();
                    return;
                }
                return;
            }

Answer 3

在您<dsp:valueof param="amount" converter="currency" locale="en_US" />的构造函数中传递socket之前，套接字似乎已关闭。

Google示例中有一个棘手的问题，在mConnectedThread中，当socket实际连接时，我们将mConnectThread设为null，并且下一个代码将不会执行：

mConnectThread

这意味着将跳过关闭套接字的if (mConnectThread != null) { mConnectThread.cancel(); mConnectThread = null; }方法。

基本上，请确保在连接套接字后不要在cancel()中调用close()方法。

无法连接到蓝牙设备

3 个答案: