分享Android 藍牙4.0(ble)開發的解決方案

2020-01-02 07:00:37

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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。由于公司需要，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.先介紹一下關于藍牙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 都是基于GATT

(2)、ATT(Attribute Protocal)

GATT是基于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連接到設備之后獲取設備的服務(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獲取到特征之后，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寫入成功之后，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后。
2.上位機主動向下位機發送一個身份驗證指令，下位機收到指令后開始給上位做應答，
3.應答成功，下位機會將測量的血壓數據傳送到上位機。
4.最后斷開連接。

希望本文對大家學習Android藍牙技術有所幫助。

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