最近，随着智能穿戴式设备、智能医疗以及智能家居的普及，蓝牙开发在移动开中显得非常的重要。由于公司需要，研究了一下，蓝牙4.0在Android中的应用。
以下是我的一些总结。
1.先介绍一下关于蓝牙4.0中的一些名词吧：
(1)、GATT(Gneric Attibute Profile)
通过ble连接，读写属性类小数据Profile通用的规范。现在所有的ble应用Profile 都是基于GATT
(2)、ATT(Attribute Protocal)
GATT是基于ATT Potocal的ATT针对BLE设备专门做的具体就是传输过程中使用尽量少的数据，每个属性都有个唯一的UUID，属性chartcteristics and Service的形式传输。
(3)、Service是Characteristic的集合。
(4)、Characteristic 特征类型。
比如，有个蓝牙ble的血压计。他可能包括多个Servvice，每个Service有包括多个Characteristic
注意：蓝牙ble只能支持Android 4.3以上的系统 SDK>=18
2.以下是开发的步骤：
2.1首先获取BluetoothManager
复制代码代码如下:
BluetoothManager bluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
2.2获取BluetoothAdapter
复制代码代码如下:
BluetoothAdapter mBluetoothAdapter = bluetoothManager.getAdapter();
2.3创建BluetoothAdapter.LeScanCallback
private BluetoothAdapter.LeScanCallback mLeScanCallback = new BluetoothAdapter.LeScanCallback() { @Override public void onLeScan(final BluetoothDevice device, int rssi, final byte[] scanRecord) { runOnUiThread(new Runnable() { @Override public void run() { try { String struuid = NumberUtils.bytes2HexString(NumberUtils.reverseBytes(scanRecord)).replace("-", "").toLowerCase(); if (device!=null && struuid.contains(DEVICE_UUID_PREFIX.toLowerCase())) { mBluetoothDevices.add(device); } } catch (Exception e) { e.printStackTrace(); } } }); } }; 2.4.开始搜索设备。
复制代码代码如下:
mBluetoothAdapter.startLeScan(mLeScanCallback);
2.5.BluetoothDevice 描述了一个蓝牙设备 提供了getAddress()设备Mac地址,getName()设备的名称。
2.6开始连接设备
/** * 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) { if (mBluetoothAdapter == null || address == null) { Log.w(TAG, "BluetoothAdapter not initialized or unspecified address."); return false; } // Previously connected device. Try to reconnect. (先前连接的设备。 尝试重新连接) 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; } 2.7连接到设备之后获取设备的服务(Service)和服务对应的Characteristic。
// 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<>(); ArrayList<ArrayList<HashMap<String, String>>> gattCharacteristicData = new ArrayList<>(); mGattCharacteristics = new ArrayList<>(); // Loops through available GATT Services. for (BluetoothGattService gattService : gattServices) { HashMap<String, String> currentServiceData = new HashMap<>(); uuid = gattService.getUuid().toString(); if (uuid.contains("ba11f08c-5f14-0b0d-1080")) {//服务的uuid //System.out.println("this gattService UUID is:" + gattService.getUuid().toString()); currentServiceData.put(LIST_NAME, "Service_OX100"); currentServiceData.put(LIST_UUID, uuid); gattServiceData.add(currentServiceData); ArrayList<HashMap<String, String>> gattCharacteristicGroupData = new ArrayList<>(); List<BluetoothGattCharacteristic> gattCharacteristics = gattService.getCharacteristics(); ArrayList<BluetoothGattCharacteristic> charas = new ArrayList<>(); // Loops through available Characteristics. for (BluetoothGattCharacteristic gattCharacteristic : gattCharacteristics) { charas.add(gattCharacteristic); HashMap<String, String> currentCharaData = new HashMap<>(); uuid = gattCharacteristic.getUuid().toString(); if (uuid.toLowerCase().contains("cd01")) { currentCharaData.put(LIST_NAME, "cd01"); } else if (uuid.toLowerCase().contains("cd02")) { currentCharaData.put(LIST_NAME, "cd02"); } else if (uuid.toLowerCase().contains("cd03")) { currentCharaData.put(LIST_NAME, "cd03"); } else if (uuid.toLowerCase().contains("cd04")) { currentCharaData.put(LIST_NAME, "cd04"); } else { currentCharaData.put(LIST_NAME, "write"); } currentCharaData.put(LIST_UUID, uuid); gattCharacteristicGroupData.add(currentCharaData); } mGattCharacteristics.add(charas); gattCharacteristicData.add(gattCharacteristicGroupData); mCharacteristicCD01 = gattService.getCharacteristic(UUID.fromString("0000cd01-0000-1000-8000-00805f9b34fb")); mCharacteristicCD02 = gattService.getCharacteristic(UUID.fromString("0000cd02-0000-1000-8000-00805f9b34fb")); mCharacteristicCD03 = gattService.getCharacteristic(UUID.fromString("0000cd03-0000-1000-8000-00805f9b34fb")); mCharacteristicCD04 = gattService.getCharacteristic(UUID.fromString("0000cd04-0000-1000-8000-00805f9b34fb")); mCharacteristicWrite = gattService.getCharacteristic(UUID.fromString("0000cd20-0000-1000-8000-00805f9b34fb")); //System.out.println("=======================Set Notification=========================="); // 开始顺序监听，第一个：CD01 mBluetoothLeService.setCharacteristicNotification(mCharacteristicCD01, true); mBluetoothLeService.setCharacteristicNotification(mCharacteristicCD02, true); mBluetoothLeService.setCharacteristicNotification(mCharacteristicCD03, true); mBluetoothLeService.setCharacteristicNotification(mCharacteristicCD04, true); } } } 2.8获取到特征之后，找到服务中可以向下位机写指令的特征，向该特征写入指令。
public void wirteCharacteristic(BluetoothGattCharacteristic characteristic) { if (mBluetoothAdapter == null || mBluetoothGatt == null) { Log.w(TAG, "BluetoothAdapter not initialized"); return; } mBluetoothGatt.writeCharacteristic(characteristic); } 2.9写入成功之后，开始读取设备返回来的数据。
private final BluetoothGattCallback mGattCallback = new BluetoothGattCallback() { @Override public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) { String intentAction; //System.out.println("=======status:" + status); if (newState == BluetoothProfile.STATE_CONNECTED) { intentAction = ACTION_GATT_CONNECTED; mConnectionState = STATE_CONNECTED; broadcastUpdate(intentAction); 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) { intentAction = ACTION_GATT_DISCONNECTED; mConnectionState = STATE_DISCONNECTED; Log.i(TAG, "Disconnected from GATT server."); broadcastUpdate(intentAction); } } @Override public void onServicesDiscovered(BluetoothGatt gatt, int status) { if (status == BluetoothGatt.GATT_SUCCESS) { broadcastUpdate(ACTION_GATT_SERVICES_DISCOVERED); } else { Log.w(TAG, "onServicesDiscovered received: " + status); } } //从特征中读取数据 @Override public void onCharacteristicRead(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) { //System.out.println("onCharacteristicRead"); if (status == BluetoothGatt.GATT_SUCCESS) { broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic); } } //向特征中写入数据 @Override public void onCharacteristicWrite(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) { //System.out.println("--------write success----- status:" + status); } /* * when connected successfully will callback this method this method can * dealwith send password or data analyze *当连接成功将回调该方法 */ @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 onDescriptorWrite(BluetoothGatt gatt, BluetoothGattDescriptor descriptor, int status) { //System.out.println("onDescriptorWriteonDescriptorWrite = " + status + ", descriptor =" + descriptor.getUuid().toString()); UUID uuid = descriptor.getCharacteristic().getUuid(); if (uuid.equals(UUID.fromString("0000cd01-0000-1000-8000-00805f9b34fb"))) { broadcastUpdate(ACTION_CD01NOTIDIED); } else if (uuid.equals(UUID.fromString("0000cd02-0000-1000-8000-00805f9b34fb"))) { broadcastUpdate(ACTION_CD02NOTIDIED); } else if (uuid.equals(UUID.fromString("0000cd03-0000-1000-8000-00805f9b34fb"))) { broadcastUpdate(ACTION_CD03NOTIDIED); } else if (uuid.equals(UUID.fromString("0000cd04-0000-1000-8000-00805f9b34fb"))) { broadcastUpdate(ACTION_CD04NOTIDIED); } } @Override public void onReadRemoteRssi(BluetoothGatt gatt, int rssi, int status) { //System.out.println("rssi = " + rssi); } }; ---------------------------------------------- //从特征中读取数据 @Override public void onCharacteristicRead(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) { //System.out.println("onCharacteristicRead"); if (status == BluetoothGatt.GATT_SUCCESS) { broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic); } } 2.10、断开连接
/** * 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(); } 2.11、数据的转换方法
// byte转十六进制字符串 public static String bytes2HexString(byte[] bytes) { String ret = ""; for (byte aByte : bytes) { String hex = Integer.toHexString(aByte & 0xFF); if (hex.length() == 1) { hex = '0' + hex; } ret += hex.toUpperCase(Locale.CHINA); } return ret; } /** * 将16进制的字符串转换为字节数组 * * @param message * @return 字节数组 */ public static byte[] getHexBytes(String message) { int len = message.length() / 2; char[] chars = message.toCharArray(); String[] hexStr = new String[len]; byte[] bytes = new byte[len]; for (int i = 0, j = 0; j < len; i += 2, j++) { hexStr[j] = "" + chars[i] + chars[i + 1]; bytes[j] = (byte) Integer.parseInt(hexStr[j], 16); } return bytes; } 大概整体就是如上的步骤，但是也是要具体根据厂家的协议来实现通信的过程。
就拿一个我们项目中的demo说一下。
一个蓝牙ble的血压计。 上位机---手机 下位机 -- 血压计
1.血压计与手机连接蓝牙之后。
2.上位机主动向下位机发送一个身份验证指令，下位机收到指令后开始给上位做应答，
3.应答成功，下位机会将测量的血压数据传送到上位机。
4.最后断开连接。
希望本文对大家学习Android蓝牙技术有所帮助。
