很久没记录东西了，前段时间研究了一哈android4.0控制多个外设的情况，注意，需要使用android版本4.3以上，蓝牙4.0及以上。
我这里使用的控制蓝牙灯泡，使用android4.3的手机，手机上的蓝牙是4.0.
记得在manifest文件中加入权限：
<uses-permission android:name="android.permission.BLUETOOTH" /> <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
先拿到BluetoothManager和BluetoothAdapter的对象。
// 初始化 Bluetooth adapter, 通过蓝牙管理器得到一个参考蓝牙适配器(API必须在以上android4.3或以上和版本) final BluetoothManager bluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE); mBluetoothAdapter = bluetoothManager.getAdapter(); // 检查设备上是否支持蓝牙 if (mBluetoothAdapter == null) { Toast.makeText(this, R.string.error_bluetooth_not_supported,Toast.LENGTH_SHORT).show(); finish(); return; }
看下是否开启了蓝牙，如果没有开启，跳转到设置去开启蓝牙。
// 为了确保设备上蓝牙能使用, 如果当前蓝牙设备没启用,弹出对话框向用户要求授予权限来启用 if (!mBluetoothAdapter.isEnabled()) { if (!mBluetoothAdapter.isEnabled()) { Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE); startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT); } }
调用startScan方法开始扫描，stopScan方法停止扫描，扫描到的设备都在回调函数里。
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); invalidateOptionsMenu(); } }, SCAN_PERIOD); mScanning = true; mBluetoothAdapter.startLeScan(mLeScanCallback); } else { mScanning = false; mBluetoothAdapter.stopLeScan(mLeScanCallback); } invalidateOptionsMenu(); }
// 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(); } }); } };
扫描后的BluetoothDevice加入到列表中，这时列表中就会有设备，通过getName可以获取设备的蓝牙名字，getAddress获取设备的蓝牙地址。
列表出来了之后，点击某个设备进行连接。
注意这里的连接跟2.0的蓝牙的连接不一样，通过设备的connectGatt方法进行连接，连接完成后会获得一个BluetoothGatt的对象，这个对象中有连接的一些重要信息，切记要保存好。
public boolean connect(final String address) { if (mBluetoothAdapter == null || address == null) { Log.w(TAG, "BluetoothAdapter not initialized or unspecified address."); return false; } if (mBluetoothDeviceAddress != null && address.equals(mBluetoothDeviceAddress) && mBluetoothGatt != null) { Log.d(TAG, "Trying to use an existing mBluetoothGatt for connection."); if (mBluetoothGatt.connect()) { 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, true, mGattCallback); Log.d(TAG, "Trying to create a new connection."); mBluetoothDeviceAddress = address; bluetoothGatts.add(mBluetoothGatt); return true; }
连接时有一个回调函数mGattCallback，这个函数中有很多设备的相关信息，比如设备的状态啊，设备中的通道哈，一些服务啊之类的。
// 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) { System.out.println("onConnectionStateChange"); String intentAction; if (status == BluetoothProfile.STATE_DISCONNECTED && newState == BluetoothProfile.STATE_CONNECTED) { intentAction = ACTION_GATT_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()); Log.e("shang", "连接成功"); mHandler.sendEmptyMessage(MESSAGE_START_SUCCESS); } else if (status == BluetoothProfile.STATE_DISCONNECTED && newState == BluetoothProfile.STATE_DISCONNECTED) { intentAction = ACTION_GATT_DISCONNECTED; setConnStatus(false); Log.e("shang", "连接失败"); Log.i(TAG, "Disconnected from GATT server."); mHandler.sendEmptyMessage(STATE_CONNECTFAILED); } } @Override public void onServicesDiscovered(BluetoothGatt gatt, int status) { System.out.println("onServicesDiscovered-----"); if (status == BluetoothGatt.GATT_SUCCESS) { broadcastUpdate(ACTION_GATT_SERVICES_DISCOVERED); displayGattServices(getSupportedGattServices()); mHandler.sendEmptyMessage(MESSAGE_BLUETOOTH_INIT); } else { Log.w(TAG, "onServicesDiscovered received: " + status); } } @Override public void onCharacteristicRead(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) { System.out.println("onCharacteristicRead"); if (status == BluetoothGatt.GATT_SUCCESS) { broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic); } } @Override public void onDescriptorWrite(BluetoothGatt gatt, BluetoothGattDescriptor descriptor, int status) { System.out.println("onDescriptorWriteonDescriptorWrite = " + status + ", descriptor =" + descriptor.getUuid().toString()); } @Override public void onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) { broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic); if (characteristic.getValue() != null) { System.out.println(characteristic.getStringValue(0)); } System.out.println("--------onCharacteristicChanged-----"); } @Override public void onReadRemoteRssi(BluetoothGatt gatt, int rssi, int status) { } public void onCharacteristicWrite(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) { System.out.println("--------write success----- status:" + status); }; };
连接时会走这个方法onConnectionStateChange，传过来的新状态是连接状态，这时在这个方法中调用一下这句：mBluetoothGatt.discoverServices()，
mBluetoothGatt是连接完成时的对象，还记得吧，调用这句后，会走回调函数的onServicesDiscovered方法。在这个方法中去获取设备的一些服务，蓝牙通道，然后通过这些通道去发送数据给外设。
查看该外设中支持的一些服务通道：
public List<BluetoothGattService> getSupportedGattServices() { if (mBluetoothGatt == null) return null; return mBluetoothGatt.getServices(); }
// 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; 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(); 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(); gattCharacteristicGroupData.add(currentCharaData); } mGattCharacteristics.add(charas); gattCharacteristicData.add(gattCharacteristicGroupData); } bluetoothGattChacteristics.add(mGattCharacteristics); }
然后就可以通过Gatt这个对像，就是蓝牙连接完成后获取到的对象，通过这个对象设置好指定的通道向设备中写入和读取数据。
写数据：
public void wirteCharacteristic(BluetoothGattCharacteristic characteristic) { if (mBluetoothAdapter == null || mBluetoothGatt == null) { Log.w(TAG, "BluetoothAdapter not initialized"); return; } mBluetoothGatt.writeCharacteristic(characteristic); }
读数据：
/** * 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); }
注意：BluetoothGattCharacteristic这个是指定的通道，蓝牙服务：
BluetoothGattCharacteristic characteristic = null; characteristic = mGattCharacteristics.get(4).get(4);
这两个数字就是从指定的服务中找到你要发送数据的那个服务。
最后，如果要进行多个连接，每次连接完成后可以将BluetoothGatt的对象放到一个list里面，获取到的服务也放到一个List里面，然后发送数据的时候调用不同的Gatt发送不同的通道数据即可。
关于蓝牙4.0的BluetoothLeGatt连接，android Samples有一个例子，发上来吧，需要的朋友可以下载看看。