蓝牙是手机和智能硬件通信常用的方式，蓝牙通信可分为传统蓝牙和低功耗蓝牙（BLE）。其中BLE的连接断开等操作可以通过Android SDK中提供的API进行操作，而传统蓝牙部分SDK并没有提供相关的API进行连接断开，只能用户自己通过手机的设置界面连接蓝牙。

那么我们如何做到在代码中自动连接传统蓝牙呢？我们可以利用反射调用Android中的私有API进行连接断开操作。

0x01 声明变量

private BluetoothDevice device;
private BluetoothAdapter blueToothAdapter;
private BluetoothHeadset mBluetoothHeadset;
private BluetoothA2dp mBluetoothA2dp;

0x02 初始化变量

blueToothAdapter = BluetoothAdapter.getDefaultAdapter();
blueToothAdapter.getProfileProxy(this, new BluetoothProfile.ServiceListener() {
                public void onServiceConnected(int profile, BluetoothProfile proxy) {
                if (profile == BluetoothProfile.HEADSET) {
                    mBluetoothHeadset = (BluetoothHeadset) proxy;
                }



            }

            public void onServiceDisconnected(int profile) {
                if (profile == BluetoothProfile.HEADSET) {
                    mBluetoothHeadset = null;
                }
            }
        },BluetoothProfile.HEADSET);
        blueToothAdapter.getProfileProxy(this, new BluetoothProfile.ServiceListener() {
            public void onServiceConnected(int profile, BluetoothProfile proxy) {
                if (profile == BluetoothProfile.A2DP){
                    mBluetoothA2dp = (BluetoothA2dp) proxy;
                }



            }

            public void onServiceDisconnected(int profile) {
                if (profile == BluetoothProfile.A2DP){
                    mBluetoothA2dp = null;
                }
            }
        },BluetoothProfile.A2DP);

0x03 连接HFP

private void connect() {

        if (mBluetoothHeadset == null) {
            return;
        }
        if (device == null) {
            return;
        }

        try {
            Log.e(TAG, \"connect\" + device.getName() + device.getAddress());
            Method connect = mBluetoothHeadset.getClass().getDeclaredMethod(\"connect\", BluetoothDevice.class);
            connect.setAccessible(true);
            connect.invoke(mBluetoothHeadset, device);
        } catch (Exception e) {
            Log.e(TAG, \"connect exception:\" + e);
            e.printStackTrace();
        }


    }

0x04 连接A2DP

private void connect2() {

        if (mBluetoothA2dp == null) {
            return;
        }
        if (device == null) {
            return;
        }
        try {
            Log.d(TAG, \"connect\" + device.getName() + device.getAddress());
            Method connect = mBluetoothA2dp.getClass().getDeclaredMethod(\"connect\", BluetoothDevice.class);
            connect.setAccessible(true);
            connect.invoke(mBluetoothA2dp, device);
        } catch (Exception e) {
            Log.e(TAG, \"connect exception:\" + e);
            e.printStackTrace();
        }
    }

0x05 断开连接

同时断开HFP和A2DP。

private void disconnect() {

        if (mBluetoothHeadset == null) {
            return;
        }
        if (device == null) {
            return;
        }

        try {
            Log.d(TAG, \"disconnect\" + device.getName());
            Method connect = mBluetoothHeadset.getClass().getDeclaredMethod(\"disconnect\", BluetoothDevice.class);
            connect.setAccessible(true);
            connect.invoke(mBluetoothHeadset, device);
        } catch (Exception e) {
            Log.e(TAG, \"disconnect exception:\" + e);
            e.printStackTrace();
        }
        if (mBluetoothA2dp == null) {
            return;
        }

        try {
            Log.d(TAG, \"disconnect\" + device.getName());
            Method connect = mBluetoothA2dp.getClass().getDeclaredMethod(\"disconnect\", BluetoothDevice.class);
            connect.setAccessible(true);
            connect.invoke(mBluetoothA2dp, device);
        } catch (Exception e) {
            Log.e(TAG, \"disconnect exception:\" + e);
            e.printStackTrace();
        }

    }

至此所有关键代码都已经完成，在使用过程中，可能会有出现连接不上的问题。实验证明先断开然后在分别连接HFP和A2DP会稳定很多。