Android藍芽4.0(ble)開發的解決方案

   最近，隨著智慧穿戴式裝置、智慧醫療以及智慧家居的普及，藍芽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，藍芽4.0在Android中的應用。以下是我的一些總結。

          1.先介紹一下關於藍芽4.0中的一些名詞吧：   

           
(1)GATT(Gneric Attibute  Profile)

通過ble連線，讀寫屬性類小資料Profile通用的規範。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裝置專門做的具體就是傳輸過程中使用盡量少的資料，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 特徵型別。

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

注意：藍芽ble只能支援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

 

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

      2.2獲取BluetoothAdapter

BluetoothAdapter mBluetoothAdapter = bluetoothManager.getAdapter();

      2.3建立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.開始搜尋裝置。

   mBluetoothAdapter.startLeScan(mLeScanCallback);

   2.5.BluetoothDevice  描述了一個藍芽裝置 提供了getAddress()裝置Mac地址,getName()裝置的名稱。

   2.6開始連線裝置

 

/**
	 * 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. (先前連線的裝置。 嘗試重新連線)
		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連線到裝置之後獲取裝置的服務(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獲取到特徵之後，找到服務中可以向下位機寫指令的特徵，向該特徵寫入指令。

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，開始讀取裝置返回來的資料。

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);
			}
		}
        //從特徵中讀取資料
		@Override
		public void onCharacteristicRead(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) {
			//System.out.println("onCharacteristicRead");
			if (status == BluetoothGatt.GATT_SUCCESS) {
				broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic);
			}
		}
        //向特徵中寫入資料
		@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
		 
		 *當連線成功將回撥該方法
		 */
		@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);
		}
	};
	
	----------------------------------------------
	  //從特徵中讀取資料
		@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、斷開連線

/**
	 * 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、資料的轉換方法

// byte轉十六進位制字串
	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進位制的字串轉換為位元組陣列
	 * 
	 * @param message
	 * @return 位元組陣列
	 */
	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訊的過程。

就那一個我們專案中的demo說一下。
一個藍芽ble的血壓計。 上位機—手機  下位機 — 血壓計
1.血壓計與手機連線藍芽之後。
2.上位機主動向下位機傳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資料傳送到上位機。
4.最後斷開連線。