android開發之藍牙配對連接的方法

新年第一篇。

最近在做藍牙開鎖的小項目，手機去連接單片機總是出現問題，和手機的連接也不穩定，看了不少藍牙方面的文檔，做了個關於藍牙連接的小結。

在做android藍牙串口連接的時候一般會使用

BluetoothSocket tmp = null;
// Get a BluetoothSocket for a connection with the
// given BluetoothDevice
try {
         tmp = device.createRfcommSocketToServiceRecord(MY_UUID);
} catch (IOException e) {
	Log.e(TAG, "create() failed", e);
}

然後是tmp賦給BluetoothSocket,接著調用connect方法進行藍牙設備的連接。

可是 BluetoothSocket 的connect方法本身就會報很多異常錯誤。

以下根據對藍牙開發的一點研究可通過以下方法解決：

方法1.先進行藍牙自動配對，配對成功，通過UUID獲得BluetoothSocket,然後執行connect()方法。

方法2.通過UUID獲得BluetoothSocket,然後先根據mDevice.getBondState()進行判斷是否需要配對，最後執行connnect()方法。

    private class ConnectThread extends Thread {
        String macAddress = "";

        public ConnectThread(String mac) {
            macAddress = mac;
        }

        public void run() {
            connecting = true;
            connected = false;
            if(mBluetoothAdapter == null){
                mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
            }
            mBluetoothDevice = mBluetoothAdapter.getRemoteDevice(macAddress);
            mBluetoothAdapter.cancelDiscovery();
            try {
                socket = mBluetoothDevice.createRfcommSocketToServiceRecord(uuid);
                
            } catch (IOException e) {
                // TODO Auto-generated catch block
                //e.printStackTrace();
                Log.e(TAG, "Socket", e);
            }             
            //adapter.cancelDiscovery();
            while (!connected && connetTime <= 10) {                
                connectDevice();
            }
            // 重置ConnectThread 
            //synchronized (BluetoothService.this) {
               //ConnectThread = null;
            //}
        }

        public void cancel() {
            try {
                socket.close();
                socket = null;
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                connecting = false;
            }
        }
    }

接下來是調用的連接設備方法connectDevice():

protected void connectDevice() {  
        try {  
            // 連接建立之前的先配對  
            if (mBluetoothDevice.getBondState() == BluetoothDevice.BOND_NONE) {  
                Method creMethod = BluetoothDevice.class  
                        .getMethod("createBond");  
                Log.e("TAG", "開始配對");  
                creMethod.invoke(mBluetoothDevice);  
            } else {  
            }  
        } catch (Exception e) {  
            // TODO: handle exception  
            //DisplayMessage("無法配對！");  
            e.printStackTrace();  
        }  
        mBluetoothAdapter.cancelDiscovery();  
        try {  
            socket.connect();  
            //DisplayMessage("連接成功!"); 
            //connetTime++;
            connected = true;
        } catch (IOException e) {  
            // TODO: handle exception  
            //DisplayMessage("連接失敗！");
            connetTime++;
            connected = false;
            try {  
                socket.close();
                socket = null;
            } catch (IOException e2) {  
                // TODO: handle exception  
                Log.e(TAG, "Cannot close connection when connection failed");  
            }  
        } finally {
            connecting = false;
        }  
    }

方法3.利用反射通過端口獲得BluetoothSocket,然後執行connect()方法。

    private class ConnectThread extends Thread {
        String macAddress = "";

        public ConnectThread(String mac) {
            macAddress = mac;
        }

        public void run() {
            connecting = true;
            connected = false;
            if(mBluetoothAdapter == null){
                mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
            }
            mBluetoothDevice = mBluetoothAdapter.getRemoteDevice(macAddress);
            mBluetoothAdapter.cancelDiscovery();
            initSocket();                         
            //adapter.cancelDiscovery();
            while (!connected && connetTime <= 10) {
                try {
                    socket.connect();
                    connected = true;
                } catch (IOException e1) {
                    connetTime++;
                    connected = false;
                    // 關閉 socket
                    try {
                        socket.close();
                        socket = null;
                    } catch (IOException e2) {
                        //TODO: handle exception  
                        Log.e(TAG, "Socket", e2);
                    }
                } finally {
                    connecting = false;
                }
                //connectDevice();
            }
            // 重置ConnectThread 
            //synchronized (BluetoothService.this) {
               //ConnectThread = null;
            //}
        }

        public void cancel() {
            try {
                socket.close();
                socket = null;
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                connecting = false;
            }
        }
    }

接下來是初始化並得到BluetoothSocket的方法

/**
     * 取得BluetoothSocket
     */
    private void initSocket() {
        BluetoothSocket temp = null;
        try {            
            Method m = mBluetoothDevice.getClass().getMethod(
                    "createRfcommSocket", new Class[] { int.class });
            temp = (BluetoothSocket) m.invoke(mBluetoothDevice, 1);//這裡端口為1            
        } catch (SecurityException e) {
            e.printStackTrace();
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }
        socket = temp;
    }

要點：1.藍牙配對和連接是兩回事，不可混為一談。

　　　2.藍牙串口連接可通過端口 （1-30）和UUID兩種方法進行操作。

　　　3.通過UUID進行藍牙連接最好先進行配對操作。