分享Android 蓝牙4.0(ble)开发的解决方案

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 

BluetoothManager bluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);  

2.2获取BluetoothAdapter

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。

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 
 html" target="_blank">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。