Ble蓝牙的使用手册

如上图所示，使用低功耗蓝牙可以包括多个Profile，一个Profile中有多个Service，一个Service中有多个Characteristic，一个Characteristic中包括一个value和多个Descriptor。

Android中进行蓝牙开发需要使用到的类的执行过程是：

1、使用BluetoothAdapter.startLeScan来扫描低功耗蓝牙设备

2、在扫描到设备的回调函数中会得到BluetoothDevice对象，并使用BluetoothAdapter.stopLeScan停止扫描

3、使用BluetoothDevice.connectGatt来获取到BluetoothGatt对象

4、执行BluetoothGatt.discoverServices，这个方法是异步操作，在回调函数onServicesDiscovered中得到status，通过判断status是否等于BluetoothGatt.GATT_SUCCESS来判断查找Service是否成功

5、如果成功了，则通过BluetoothGatt.getService来获取BluetoothGattService

6、接着通过BluetoothGattService.getCharacteristic获取BluetoothGattCharacteristic

7、然后通过BluetoothGattCharacteristic.getDescriptor获取BluetoothGattDescriptor

使用低功耗蓝牙需要用到的权限：
<uses-permission android:name="android.permission.BLUETOOTH"/>
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>

下面介绍怎样使用BLE:1、准备BLE    1）获取BluetoothAdapter     BluetoothAdapter是从系统服务获取到的，全系统就一个。// Initializes Bluetooth adapter.final BluetoothManager bluetoothManager =        (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);mBluetoothAdapter = bluetoothManager.getAdapter();

 2）检测蓝牙是否打开    如果蓝牙未打开，系统会自动打开，会弹出系统框展示打开蓝牙。private BluetoothAdapter mBluetoothAdapter;...// Ensures Bluetooth is available on the device and it is enabled. If not,// displays a dialog requesting user permission to enable Bluetooth.if (mBluetoothAdapter == null || !mBluetoothAdapter.isEnabled()) {    Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);    startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);}

2、查找BLE设备   因为扫描BLE设备是电源密集型操作，浪费电量，因此要保证以下原则：    1）扫描到需要的设备后，马上停止扫描；    2）给扫描一个时间限制   扫描示例代码如下：/** * Activity for scanning and displaying available BLE devices. */public class DeviceScanActivity extends ListActivity {    private BluetoothAdapter mBluetoothAdapter;    private boolean mScanning;    private Handler mHandler;    // Stops scanning after 10 seconds.    private static final long SCAN_PERIOD = 10000;    ...    private void scanLeDevice(final boolean enable) {        if (enable) {            // Stops scanning after a pre-defined scan period.            mHandler.postDelayed(new Runnable() {                @Override                public void run() {                    mScanning = false;                    mBluetoothAdapter.stopLeScan(mLeScanCallback);                }            }, SCAN_PERIOD);            mScanning = true;            mBluetoothAdapter.startLeScan(mLeScanCallback);        } else {            mScanning = false;            mBluetoothAdapter.stopLeScan(mLeScanCallback);        }        ...    }...}     如果只是要扫描到特定类型的设备，则使用接口 startLeScan(UUID[], BluetoothAdapter.LeScanCallback)，通过UUID来查找设备。    扫描回调的代码如下所示：private LeDeviceListAdapter mLeDeviceListAdapter;...// Device scan callback.private BluetoothAdapter.LeScanCallback mLeScanCallback =        new BluetoothAdapter.LeScanCallback() {    @Override    public void onLeScan(final BluetoothDevice device, int rssi,            byte[] scanRecord) {        runOnUiThread(new Runnable() {           @Override           public void run() {               mLeDeviceListAdapter.addDevice(device);               mLeDeviceListAdapter.notifyDataSetChanged();           }       });   }};注意：我们既可以扫描BLE设备，也可以扫描普通蓝牙设备，也可以同时将BLE设备和普通蓝牙设备一起扫描到。

3、连接到GATT Server   获取到BluetoothGatt实例，mBluetoothGatt = device.connectGatt(this, false, mGattCallback);    具体实例如下：// A service that interacts with the BLE device via the Android BLE API.public class BluetoothLeService extends Service {    private final static String TAG = BluetoothLeService.class.getSimpleName();    private BluetoothManager mBluetoothManager;    private BluetoothAdapter mBluetoothAdapter;    private String mBluetoothDeviceAddress;    private BluetoothGatt mBluetoothGatt;    private int mConnectionState = STATE_DISCONNECTED;    private static final int STATE_DISCONNECTED = 0;    private static final int STATE_CONNECTING = 1;    private static final int STATE_CONNECTED = 2;    public final static String ACTION_GATT_CONNECTED =            "com.example.bluetooth.le.ACTION_GATT_CONNECTED";    public final static String ACTION_GATT_DISCONNECTED =            "com.example.bluetooth.le.ACTION_GATT_DISCONNECTED";    public final static String ACTION_GATT_SERVICES_DISCOVERED =            "com.example.bluetooth.le.ACTION_GATT_SERVICES_DISCOVERED";    public final static String ACTION_DATA_AVAILABLE =            "com.example.bluetooth.le.ACTION_DATA_AVAILABLE";    public final static String EXTRA_DATA =            "com.example.bluetooth.le.EXTRA_DATA";    public final static UUID UUID_HEART_RATE_MEASUREMENT =            UUID.fromString(SampleGattAttributes.HEART_RATE_MEASUREMENT);    // Various callback methods defined by the BLE API.    private final BluetoothGattCallback mGattCallback =            new BluetoothGattCallback() {        @Override        public void onConnectionStateChange(BluetoothGatt gatt, int status,                int newState) {            String intentAction;            if (newState == BluetoothProfile.STATE_CONNECTED) {                intentAction = ACTION_GATT_CONNECTED;                mConnectionState = STATE_CONNECTED;                broadcastUpdate(intentAction);                Log.i(TAG, "Connected to GATT server.");                Log.i(TAG, "Attempting to start service discovery:" +                        mBluetoothGatt.discoverServices());            } else if (newState == BluetoothProfile.STATE_DISCONNECTED) {                intentAction = ACTION_GATT_DISCONNECTED;                mConnectionState = STATE_DISCONNECTED;                Log.i(TAG, "Disconnected from GATT server.");                broadcastUpdate(intentAction);            }        }        @Override        // New services discovered        public void onServicesDiscovered(BluetoothGatt gatt, int status) {            if (status == BluetoothGatt.GATT_SUCCESS) {                broadcastUpdate(ACTION_GATT_SERVICES_DISCOVERED);            } else {                Log.w(TAG, "onServicesDiscovered received: " + status);            }        }        @Override        // Result of a characteristic read operation        public void onCharacteristicRead(BluetoothGatt gatt,                BluetoothGattCharacteristic characteristic,                int status) {            if (status == BluetoothGatt.GATT_SUCCESS) {                broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic);            }        }     ...    };...}    其中，discoverService方式是异步的，它的回调方法是上面代码中的onServiceDiscovered。private void broadcastUpdate(final String action) {    final Intent intent = new Intent(action);    sendBroadcast(intent);}private void broadcastUpdate(final String action,                             final BluetoothGattCharacteristic characteristic) {    final Intent intent = new Intent(action);    // This is special handling for the Heart Rate Measurement profile. Data    // parsing is carried out as per profile specifications.    if (UUID_HEART_RATE_MEASUREMENT.equals(characteristic.getUuid())) {        int flag = characteristic.getProperties();        int format = -1;        if ((flag & 0x01) != 0) {            format = BluetoothGattCharacteristic.FORMAT_UINT16;            Log.d(TAG, "Heart rate format UINT16.");        } else {            format = BluetoothGattCharacteristic.FORMAT_UINT8;            Log.d(TAG, "Heart rate format UINT8.");        }        final int heartRate = characteristic.getIntValue(format, 1);        Log.d(TAG, String.format("Received heart rate: %d", heartRate));        intent.putExtra(EXTRA_DATA, String.valueOf(heartRate));    } else {        // For all other profiles, writes the data formatted in HEX.        final byte[] data = characteristic.getValue();        if (data != null && data.length > 0) {            final StringBuilder stringBuilder = new StringBuilder(data.length);            for(byte byteChar : data)                stringBuilder.append(String.format("%02X ", byteChar));            intent.putExtra(EXTRA_DATA, new String(data) + "\n" +                    stringBuilder.toString());        }    }    sendBroadcast(intent);}// Handles various events fired by the Service.// ACTION_GATT_CONNECTED: connected to a GATT server.// ACTION_GATT_DISCONNECTED: disconnected from a GATT server.// ACTION_GATT_SERVICES_DISCOVERED: discovered GATT services.// ACTION_DATA_AVAILABLE: received data from the device. This can be a// result of read or notification operations.private final BroadcastReceiver mGattUpdateReceiver = new BroadcastReceiver() {    @Override    public void onReceive(Context context, Intent intent) {        final String action = intent.getAction();        if (BluetoothLeService.ACTION_GATT_CONNECTED.equals(action)) {            mConnected = true;            updateConnectionState(R.string.connected);            invalidateOptionsMenu();        } else if (BluetoothLeService.ACTION_GATT_DISCONNECTED.equals(action)) {            mConnected = false;            updateConnectionState(R.string.disconnected);            invalidateOptionsMenu();            clearUI();        } else if (BluetoothLeService.                ACTION_GATT_SERVICES_DISCOVERED.equals(action)) {            // Show all the supported services and characteristics on the            // user interface.            displayGattServices(mBluetoothLeService.getSupportedGattServices());        } else if (BluetoothLeService.ACTION_DATA_AVAILABLE.equals(action)) {            displayData(intent.getStringExtra(BluetoothLeService.EXTRA_DATA));        }    }};

4、读BLE属性    一旦获取到GATT的Services，就可以读写他们的属性了，实例如下：public class DeviceControlActivity extends Activity {    ...    // Demonstrates how to iterate through the supported GATT    // Services/Characteristics.    // In this sample, we populate the data structure that is bound to the    // ExpandableListView on the UI.    private void displayGattServices(List<BluetoothGattService> gattServices) {        if (gattServices == null) return;        String uuid = null;        String unknownServiceString = getResources().                getString(R.string.unknown_service);        String unknownCharaString = getResources().                getString(R.string.unknown_characteristic);        ArrayList<HashMap<String, String>> gattServiceData =                new ArrayList<HashMap<String, String>>();        ArrayList<ArrayList<HashMap<String, String>>> gattCharacteristicData                = new ArrayList<ArrayList<HashMap<String, String>>>();        mGattCharacteristics =                new ArrayList<ArrayList<BluetoothGattCharacteristic>>();        // Loops through available GATT Services.        for (BluetoothGattService gattService : gattServices) {            HashMap<String, String> currentServiceData =                    new HashMap<String, String>();            uuid = gattService.getUuid().toString();            currentServiceData.put(                    LIST_NAME, SampleGattAttributes.                            lookup(uuid, unknownServiceString));            currentServiceData.put(LIST_UUID, uuid);            gattServiceData.add(currentServiceData);            ArrayList<HashMap<String, String>> gattCharacteristicGroupData =                    new ArrayList<HashMap<String, String>>();            List<BluetoothGattCharacteristic> gattCharacteristics =                    gattService.getCharacteristics();            ArrayList<BluetoothGattCharacteristic> charas =                    new ArrayList<BluetoothGattCharacteristic>();           // Loops through available Characteristics.            for (BluetoothGattCharacteristic gattCharacteristic :                    gattCharacteristics) {                charas.add(gattCharacteristic);                HashMap<String, String> currentCharaData =                        new HashMap<String, String>();                uuid = gattCharacteristic.getUuid().toString();                currentCharaData.put(                        LIST_NAME, SampleGattAttributes.lookup(uuid,                                unknownCharaString));                currentCharaData.put(LIST_UUID, uuid);                gattCharacteristicGroupData.add(currentCharaData);            }            mGattCharacteristics.add(charas);            gattCharacteristicData.add(gattCharacteristicGroupData);         }    ...    }...}  在获取Service的时候，每个蓝牙设备都会有两个默认的Service，它们和对应的UUID分别如下：Bluetooth Generic Access Profile    {00001800-0000-1000-8000-00805f9b34fb}Bluetooth Generic Attribute Profile {00001801-0000-1000-8000-00805F9B34FB}

5、收到GATT通知   如果设备主动给手机发信息，则可以通过notification的方式，这种方式不用手机去轮询地读设备上的数据。手机可以用如下方式给设备设置notification功能。private BluetoothGatt mBluetoothGatt;BluetoothGattCharacteristic characteristic;boolean enabled;...mBluetoothGatt.setCharacteristicNotification(characteristic, enabled);...BluetoothGattDescriptor descriptor = characteristic.getDescriptor(        UUID.fromString(SampleGattAttributes.CLIENT_CHARACTERISTIC_CONFIG));descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);mBluetoothGatt.writeDescriptor(descriptor);    如果notificaiton方式对于某个Characteristic是enable的，那么当设备上的这个Characteristic改变时，手机上的onCharacteristicChanged() 回调就会被促发。如下所示：@Override// Characteristic notificationpublic void onCharacteristicChanged(BluetoothGatt gatt,        BluetoothGattCharacteristic characteristic) {    broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic);}6、关闭客户端蓝牙public void close() {    if (mBluetoothGatt == null) {        return;    }    mBluetoothGatt.close();    mBluetoothGatt = null;}

在我的项目中的一小部分步骤总结：

1，开启一个线程去扫描蓝牙设备，将有的蓝牙设备显示在ListView中，点击item触发监听去连接蓝牙设备，将蓝牙设备的地址返回给上一页2，得到Intent中的 BluetoothDevice.EXTRA_DEVICE ，开启 BlueToothService服务，将蓝牙的地址存储到sqlite中3，在BlueToothService 中bindService      UartService  启动UartService   注册广播接收器：UARTStatusChangeReceiver   用于连接、接收、发送的蓝牙服务   注册广播接收器：BluetoothStateListener  用于监听蓝牙状态4,UartService 用于连接、接收、发送的蓝牙服务   提供的connect方法：connect(final String address)  1，判断传递过来的地址是否为空，  2，判断以前是否连接过，  3，通过mBluetoothAdapter.getRemoteDevice(address);得到蓝牙设备  4，device.connectGatt(this, false, mGattCallback)