分享Android 藍牙4.0(ble)開發的解決方案

最近，隨著智能穿戴式設備、智能醫療以及智能家居的普及，藍牙開發在移動開中顯得非常的重要。由於公司需要，研究了一下，藍牙4.0在Android中的應用。

以下是我的一些總結。

1.先介紹一下關於藍牙4.0中的一些名詞吧：   
(1)、GATT(Gneric Attibute  Profile)

通過ble連接，讀寫屬性類小數據Profile通用的規范。現在所有的ble應用Profile  都是基於GATT
(2)、ATT(Attribute Protocal)
GATT是基於ATT Potocal的ATT針對BLE設備專門做的具體就是傳輸過程中使用盡量少的數據，每個屬性都有個唯一的UUID，屬性chartcteristics and Service的形式傳輸。

(3)、Service是Characteristic的集合。
(4)、Characteristic 特征類型。

比如，有個藍牙ble的血壓計。他可能包括多個Servvice，每個Service有包括多個Characteristic

注意：藍牙ble只能支持Android 4.3以上的系統 SDK>=18

2.以下是開發的步驟：
2.1首先獲取BluetoothManager 

復制代碼 代碼如下:BluetoothManager bluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE); 

2.2獲取BluetoothAdapter

復制代碼 代碼如下:BluetoothAdapter mBluetoothAdapter = bluetoothManager.getAdapter(); 

2.3創建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.開始搜索設備。

復制代碼 代碼如下:mBluetoothAdapter.startLeScan(mLeScanCallback); 

2.5.BluetoothDevice  描述了一個藍牙設備 提供了getAddress()設備Mac地址,getName()設備的名稱。
2.6開始連接設備

 /** 
  * 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. (先前連接的設備。 嘗試重新連接) 
  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連接到設備之後獲取設備的服務(Service)和服務對應的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")) {//服務的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=========================="); 
   // 開始順序監聽，第一個：CD01 
   mBluetoothLeService.setCharacteristicNotification(mCharacteristicCD01, true); 
   mBluetoothLeService.setCharacteristicNotification(mCharacteristicCD02, true); 
   mBluetoothLeService.setCharacteristicNotification(mCharacteristicCD03, true); 
   mBluetoothLeService.setCharacteristicNotification(mCharacteristicCD04, true); 
  } 
 } 
} 

2.8獲取到特征之後，找到服務中可以向下位機寫指令的特征，向該特征寫入指令。

public void wirteCharacteristic(BluetoothGattCharacteristic characteristic) { 
 
  if (mBluetoothAdapter == null || mBluetoothGatt == null) { 
   Log.w(TAG, "BluetoothAdapter not initialized"); 
   return; 
  } 
 
  mBluetoothGatt.writeCharacteristic(characteristic); 
 
 } 

2.9寫入成功之後，開始讀取設備返回來的數據。

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); 
   } 
  } 
  //從特征中讀取數據 
  @Override 
  public void onCharacteristicRead(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) { 
   //System.out.println("onCharacteristicRead"); 
   if (status == BluetoothGatt.GATT_SUCCESS) { 
    broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic); 
   } 
  } 
  //向特征中寫入數據 
  @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 
   
   *當連接成功將回調該方法 
   */ 
  @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); 
  } 
 }; 
  
 ---------------------------------------------- 
  //從特征中讀取數據 
  @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、斷開連接

/** 
  * 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、數據的轉換方法

// byte轉十六進制字符串 
 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; 
 } 

/** 
  * 將16進制的字符串轉換為字節數組 
  * 
  * @param message 
  * @return 字節數組 
  */ 
 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; 
 } 

大概整體就是如上的步驟，但是也是要具體根據廠家的協議來實現通信的過程。

就拿一個我們項目中的demo說一下。
一個藍牙ble的血壓計。 上位機---手機  下位機 -- 血壓計
1.血壓計與手機連接藍牙之後。
2.上位機主動向下位機發送一個身份驗證指令，下位機收到指令後開始給上位做應答，
3.應答成功，下位機會將測量的血壓數據傳送到上位機。
4.最後斷開連接。

希望本文對大家學習Android藍牙技術有所幫助。