java - 蓝牙无法连接到OBD2

Question

我正在使用我在 github 上找到的一个应用程序来测试和查看蓝牙聊天如何与我的 ELM327 一起工作，但是当我配对并尝试连接它时，连接失败。在那之后，我尝试拿到我的旧手机并设置与它的连接并且它有效。我什至可以毫无问题地发送数据。我认为这可能与低功耗蓝牙有关(我是 Java 的新手，所以它只是一个赌注)但我真的不知道如何弄清楚，因为 logcat 没有给我错误，应用程序只是说它无法连接设备。

这就是我用来测试和了解它的应用程序的来源: https://github.com/DevExchanges/BluetoothChatAppAndroid

 // runs while listening for incoming connections
private class AcceptThread extends Thread {
    private final BluetoothServerSocket serverSocket;

    public AcceptThread() {
        BluetoothServerSocket tmp = null;
        try {
            tmp = bluetoothAdapter.listenUsingInsecureRfcommWithServiceRecord(APP_NAME, MY_UUID);
        } catch (IOException ex) {
            ex.printStackTrace();
        }
        serverSocket = tmp;
    }

    public void run() {
        setName("AcceptThread");
        BluetoothSocket socket;
        while (state != STATE_CONNECTED) {
            try {
                socket = serverSocket.accept();
            } catch (IOException e) {
                break;
            }

            // If a connection was accepted
            if (socket != null) {
                synchronized (ChatController.this) {
                    switch (state) {
                        case STATE_LISTEN:
                        case STATE_CONNECTING:
                            // start the connected thread.
                            connected(socket, socket.getRemoteDevice());
                            break;
                        case STATE_NONE:
                        case STATE_CONNECTED:
                            // Either not ready or already connected. Terminate
                            // new socket.
                            try {
                                socket.close();
                            } catch (IOException e) {
                            }
                            break;
                    }
                }
            }
        }
    }

    public void cancel() {
        try {
            serverSocket.close();
        } catch (IOException e) {
        }
    }
}

// runs while attempting to make an outgoing connection
private class ConnectThread extends Thread {
    private final BluetoothSocket socket;
    private final BluetoothDevice device;

    public ConnectThread(BluetoothDevice device) {
        this.device = device;
        BluetoothSocket tmp = null;
        try {
            tmp = device.createInsecureRfcommSocketToServiceRecord(MY_UUID);
        } catch (IOException e) {
            e.printStackTrace();
        }
        socket = tmp;
    }

    public void run() {
        setName("ConnectThread");

        // Always cancel discovery because it will slow down a connection
        bluetoothAdapter.cancelDiscovery();

        // Make a connection to the BluetoothSocket
        try {
            socket.connect();
        } catch (IOException e) {
            try {
                socket.close();
            } catch (IOException e2) {
            }
            connectionFailed();
            return;
        }

        // Reset the ConnectThread because we're done
        synchronized (ChatController.this) {
            connectThread = null;
        }

        // Start the connected thread
        connected(socket, device);
    }

    public void cancel() {
        try {
            socket.close();
        } catch (IOException e) {
        }
    }
}

Answer 1

从 Android 6 开始，您必须在手机上启用定位功能才能使用 BLE。仅授予应用位置权限是不够的。您可以阅读更多相关信息 here .