藍牙4.0在Android中的應用

時間  2020-11-19
標籤 android 數組 async ide oop this code server 欄目 Android 简体版
原文   原文鏈接

最近，隨着智能穿戴式設備、智能醫療以及智能家居的普及，藍牙開發在移動開中顯得很是的重要。因爲公司須要，研究了一下，藍牙4.0在Android中的應用。如下是個人一些總結。android

1.先介紹一下關於藍牙4.0中的一些名詞吧：

(1)GATT(Gneric Attibute  Profile)

經過ble鏈接，讀寫屬性類小數據Profile通用的規範。如今全部的ble應用Profile 都是基於GATT (2)ATT(Attribute Protocal) GATT是基於ATT Potocal的ATT針對BLE設備專門作的具體就是傳輸過程當中使用盡可能少的數據，每一個屬性都有個惟一的UUID，屬性chartcteristics and Service的形式傳輸。 (3)Service是Characteristic的集合。 (4).Characteristic 特徵類型。 好比。有個藍牙ble的血壓計。他可能包括多個Servvice，每一個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數組

2.如下是開發的步驟：

2.1首先獲取BluetoothManager

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

2.2獲取BluetoothAdapter

BluetoothAdapter mBluetoothAdapter = bluetoothManager.getAdapter();ide

2.3建立BluetoothAdapter.LeScanCallback

private BluetoothAdapter.LeScanCallback mLeScanCallback = new BluetoothAdapter.LeScanCallback() {oop

@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。

mBluetoothAdapter.startLeScan(mLeScanCallback);ui

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開始鏈接設備

/** * 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; }this

// Previously connected device. Try to reconnect. (先前鏈接的設備。 嘗試從新鏈接)
	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鏈接到設備以後獲取設備的服務(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獲取到特徵以後，找到服務中能夠向下位機寫指令的特徵，向該特徵寫入指令。 public void wirteCharacteristic(BluetoothGattCharacteristic characteristic) {code

if (mBluetoothAdapter == null || mBluetoothGatt == null) {
		Log.w(TAG, "BluetoothAdapter not initialized");
		return;
	}

	mBluetoothGatt.writeCharacteristic(characteristic);

}

###2.9寫入成功以後，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());server

} 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);
		}
	}
    //向特徵中寫入數據
	@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
	 
	 *當鏈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);
	}
};

----------------------------------------------
  //從特徵中讀取數據
	@Override
	public void onCharacteristicRead(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) {
		//System.out.println("onCharacteristicRead");
		if (status == BluetoothGatt.GATT_SUCCESS) {
			broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic);
		}
	}

###2.十、斷開鏈接 /** * 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(); } ###2.十一、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; }ip

/** * 將16進制的字符串轉換爲字節數組 * * @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; }

大概總體就是如上的步驟。可是也是要具體根據廠家的協議來實現通訊的過程。

###就那一個咱們項目中的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.血壓計與手機鏈接藍牙以後。 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作應答， 3.應答成功，下位機會將測量的血壓數據傳送到上位機。 4.最後斷開鏈接。

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