Android BLE （低功耗蓝牙）应用

public class UartService extends Service {
    private final static String TAG = UartService.class.getSimpleName();
    List<BluetoothGattService> serviceList = new ArrayList<BluetoothGattService>();//发现的服务列表

    private BluetoothAdapter mBluetoothAdapter;//本地蓝牙适配器
    private String mBluetoothDeviceAddress;//本地蓝牙MAC地址
    private BluetoothGatt mBluetoothGatt;//GTAA
    /**
     * 假设生产商提供了一个服务，该服务里面有两个特征值
     */
    private BluetoothGattService mBluetoothGattService;//gatt服务
    private BluetoothGattCharacteristic mBluetoothGattCharacteristic1;//gatt特征值1
    private BluetoothGattCharacteristic mBluetoothGattCharacteristic2;//gatt特征值2
    private int mConnectionState = STATE_DISCONNECTED;

    //连接状态常量
    private static final int STATE_DISCONNECTED = 0;
    private static final int STATE_CONNECTING = 1;
    private static final int STATE_CONNECTED = 2;

    //蓝牙厂商提供的UUID
    private static final UUID UUID_SERVICE = UUID.fromString("0000fff0-0000-1000-8000-00805f9b34fb"); //服务
    private static final UUID UUID_CHARA1 = UUID.fromString("0000fff1-0000-1000-8000-00805f9b34fb"); //特征值1
    private static final UUID UUID_CHARA2 = UUID.fromString("0000fff4-0000-1000-8000-00805f9b34fb"); //特征值2
    

    // Implements callback methods for GATT events that the app cares about.  For example,
    // connection change and services discovered.
    private final BluetoothGattCallback mGattCallback = new BluetoothGattCallback() {
        @Override
        public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
            if (newState == BluetoothProfile.STATE_CONNECTED) {
                mConnectionState = STATE_CONNECTED;
                Log.i(TAG, "Connected to GATT server.");
                // Attempts to discover services after successful connection.
                Log.i(TAG, "Attempting to start service discovery:" +
                        mBluetoothGatt.discoverServices());
            } else if (newState == BluetoothProfile.STATE_DISCONNECTED) {
                mConnectionState = STATE_DISCONNECTED;
                Log.i(TAG, "Disconnected from GATT server.");
            }
        }

        @Override
        public void onServicesDiscovered(BluetoothGatt gatt, int status) {//服务被发现
            if (status == BluetoothGatt.GATT_SUCCESS) {
                System.out.println("Service has bean discover.");
                mBluetoothGattService = gatt.getService(UUID_SERVICE);//发现服务
            } else {
                Log.w(TAG, "onServicesDiscovered received: " + status);
            }
        }

        @Override
        public void onCharacteristicRead(BluetoothGatt gatt,
                                         BluetoothGattCharacteristic characteristic,
                                         int status) {
            if (status == BluetoothGatt.GATT_SUCCESS) {
                Utiles.setData(characteristic);
            }
        }

        @Override
        public void onCharacteristicWrite(BluetoothGatt gatt,
                                          BluetoothGattCharacteristic characteristic,
                                          int status) {
        }

        @Override
        public void onCharacteristicChanged(BluetoothGatt gatt,
                                            BluetoothGattCharacteristic characteristic) {
        }
    };


    public class LocalBinder extends Binder {
        UartService getService() {
            return UartService.this;
        }
    }

    @Override
    public IBinder onBind(Intent intent) {
        return mBinder;
    }

    @Override
    public boolean onUnbind(Intent intent) {
        // After using a given device, you should make sure that BluetoothGatt.close() is called
        // such that resources are cleaned up properly.  In this particular example, close() is
        // invoked when the UI is disconnected from the Service.
        close();
        return super.onUnbind(intent);
    }

    private final IBinder mBinder = new LocalBinder();

    /**
     * Initializes a reference to the local Bluetooth adapter.
     *
     * @return Return true if the initialization is successful.
     */
    public boolean initialize() {//初始化
        // For API level 18 and above, get a reference to BluetoothAdapter through
        // BluetoothManager.
        mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
        if (mBluetoothAdapter == null) {
            Log.e(TAG, "Unable to obtain a BluetoothAdapter.");
            return false;
        }

        return true;
    }

    /**
     * Connects to the GATT server hosted on the Bluetooth LE device.
     *
     * @param address The device address of the destination device.
     *
     * @return Return true if the connection is initiated successfully. The connection result
     *         is reported asynchronously through the
     *         {@code BluetoothGattCallback#onConnectionStateChange(android.bluetooth.BluetoothGatt, int, int)}
     *         callback.
     */
    public boolean connect(final String address) {//连接服务
        if (mBluetoothAdapter == null || address == null) {
            Log.w(TAG, "BluetoothAdapter not initialized or unspecified address.");
            return false;
        }

        // Previously connected device.  Try to reconnect.
        if (mBluetoothDeviceAddress != null && address.equals(mBluetoothDeviceAddress)
                && mBluetoothGatt != null) {
            Log.d(TAG, "Trying to use an existing mBluetoothGatt for connection.");
            if (mBluetoothGatt.connect()) {
                mConnectionState = STATE_CONNECTING;
                return true;
            } else {
                return false;
            }
        }

        final BluetoothDevice device = mBluetoothAdapter.getRemoteDevice(address);
        if (device == null) {
            Log.w(TAG, "Device not found.  Unable to connect.");
            return false;
        }
        // We want to directly connect to the device, so we are setting the autoConnect
        // parameter to false.
        mBluetoothGatt = device.connectGatt(this, false, mGattCallback);
        Log.d(TAG, "Trying to create a new connection.");
        mBluetoothDeviceAddress = address;
        mConnectionState = STATE_CONNECTING;
        return true;
    }

    /**
     * Disconnects an existing connection or cancel a pending connection. The disconnection result
     * is reported asynchronously through the
     * {@code BluetoothGattCallback#onConnectionStateChange(android.bluetooth.BluetoothGatt, int, int)}
     * callback.
     */
    public void disconnect() {
        if (mBluetoothAdapter == null || mBluetoothGatt == null) {
            Log.w(TAG, "BluetoothAdapter not initialized");
            return;
        }
        mBluetoothGatt.disconnect();
    }

    /**
     * After using a given BLE device, the app must call this method to ensure resources are
     * released properly.
     */
    public void close() {
        if (mBluetoothGatt == null) {
            return;
        }
        mBluetoothGatt.close();
        mBluetoothGatt = null;
    }

    /**
     * Request a read on a given {@code BluetoothGattCharacteristic}. The read result is reported
     * asynchronously through the {@code BluetoothGattCallback#onCharacteristicRead(android.bluetooth.BluetoothGatt, android.bluetooth.BluetoothGattCharacteristic, int)}
     * callback.
     *
     * @param characteristic The characteristic to read from.
     */
    public void readCharacteristic(BluetoothGattCharacteristic characteristic) {
        if (mBluetoothAdapter == null || mBluetoothGatt == null) {
            Log.w(TAG, "BluetoothAdapter not initialized");
            return;
        }
        mBluetoothGatt.readCharacteristic(characteristic);
    }

    /**
     * Request a read on a given {@code BluetoothGattCharacteristic}. The read result is reported
     * asynchronously through the {@code BluetoothGattCallback#onCharacteristicRead(android.bluetooth.BluetoothGatt, android.bluetooth.BluetoothGattCharacteristic, int)}
     * callback.
     *
     * @param characteristic The characteristic to read from.
     */
    public void writeCharacteristic(BluetoothGattCharacteristic characteristic) {
        if (mBluetoothAdapter == null || mBluetoothGatt == null) {
            Log.w(TAG, "BluetoothAdapter not initialized");
            return;
        }
        mBluetoothGatt.writeCharacteristic(characteristic);
    }
    
    public boolean writeCharacteristic1Info(String s){
        if(mBluetoothGattService==null){
            return false;
        }
        mBluetoothGattCharacteristic1 = mBluetoothGattService.getCharacteristic(UUID_CHARA1);//获得特征值1
        mBluetoothGattCharacteristic1.setValue(s.getBytes());
        writeCharacteristic(mBluetoothGattCharacteristic1);
        return true;
    }

    /**
     * Enables or disables notification on a give characteristic.
     *
     * @param characteristic Characteristic to act on.
     * @param enabled If true, enable notification.  False otherwise.
     */
    public void setCharacteristicNotification(BluetoothGattCharacteristic characteristic,
                                              boolean enabled) {
        if (mBluetoothAdapter == null || mBluetoothGatt == null) {
            Log.w(TAG, "BluetoothAdapter not initialized");
            return;
        }
        mBluetoothGatt.setCharacteristicNotification(characteristic, enabled);
    }
    

    /**
     * Retrieves a list of supported GATT services on the connected device. This should be
     * invoked only after {@code BluetoothGatt#discoverServices()} completes successfully.
     *
     * @return A {@code List} of supported services.
     */
    public List<BluetoothGattService> getSupportedGattServices() {
        if (mBluetoothGatt == null) return null;

        return mBluetoothGatt.getServices();
    }
    
    @Override//使用startService启动服务时回调
    public int onStartCommand(Intent intent, int flags, int startId) {
        System.out.println("UartService Start");
        return super.onStartCommand(intent, flags, startId);
    }
}

 mBluetoothGattService = gatt.getService(UUID_SERVICE);//发现服务
 List<BluetoothGattCharacteristic> characteristics = mBluetoothGattService.getCharacteristics();
 if(characteristics.size()!=2){return;}//如果此服务不是有2个特征值，说明不是我们要的服务
 for (BluetoothGattCharacteristic bluetoothGattCharacteristic : characteristics) {
      setCharacteristicNotification(bluetoothGattCharacteristic, true);
 }
 mBluetoothGattCharacteristic1 = characteristics.get(0);
 mBluetoothGattCharacteristic2 = characteristics.get(1);