低功耗蓝牙BLE外围模式(peripheral)-使用BLE作为服务端

低功耗蓝牙BLE外围模式(peripheral)-使用BLE作为服务端Android对外模模式(peripheral)的支持从Android5.0开始才支持关键术语和概念以下是关键BLE术语和概念的摘要:
  • 通用属性简档(GATT) - GATT简档是用于通过BLE链路发送和接收称为“属性”的短数据块的一般规范。 所有当前的低能量应用配置文件都基于GATT。
    蓝牙SIG为低能量设备定义了许多配置文件 。 配置文件是设备在特定应用程序中的工作方式的规范。 请注意,设备可以实现多个配置文件。 例如,设备可以包含心率监视器和电池水平检测器。
  • 属性协议(ATT) -GATT建立在属性协议(ATT)之上。 这也称为GATT / ATT。 ATT经过优化,可在BLE设备上运行。 为此,它使用尽可能少的字节。 每个属性由通用唯一标识符(UUID)唯一标识,UUID是用于唯一标识信息的字符串ID的标准化128位格式。 由ATT传送的属性被格式化为特征和服务 。
  • 特性 -A特性包含描述特性值的单个值和0-n个描述符。 一个特性可以被认为是一个类型,类似于类。
  • 描述符 - 描述符是描述特征值的定义属性。 例如,描述符可以指定人类可读的描述,特征值的可接受范围或特征值的特定的测量单位。
  • 服务 - 服务是一个集合的特点。 例如,您可以有一个名为“心率监视器”的服务,其中包括诸如“心率测量”的特征。 您可以在bluetooth.org上找到现有基于GATT的个人资料和服务的列表 。
  • 角色和职责以下是Android设备与BLE设备互动时适用的角色和职责:中央与外围。 这适用于BLE连接本身。 处于中心角色的设备扫描,寻找广告,并且外围角色中的设备进行广告。GATT服务器与GATT客户端。 这决定了两个设备在建立连接后如何相互通信。BLE权限首先,需要在manifest中声明使用蓝牙和操作蓝牙的权限在应用程序清单文件中声明蓝牙权限。 例如:

    如果您要声明自己的应用只适用于支持BLE的设备,请在应用清单中包含以下内容:<uses-feature android:name =“android.hardware.bluetooth_le”android:required =“true”/>不过,如果您想让应用程式适用于不支援BLE的装置,您仍应在应用的清单中加入这个元素,但required="false"设为required="false" 。
    然后在运行时,您可以通过使用PackageManager.hasSystemFeature()确定BLE可用性: // Use this check to determine whether BLE is supported on the device. Then // you can selectively disable BLE-related features. if (!getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH_LE)) { Toast.makeText(this, R.string.ble_not_supported, Toast.LENGTH_SHORT).show(); finish(); }在android 6.0 以后,要想获得蓝牙扫描结果,还需要下面的权限 <manifest ... > <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" /> ... <!-- Needed only if your app targets Android 5.0 (API level 21) or higher. --> <uses-feature android:name="android.hardware.location.gps" /> ... </manifest>设置蓝牙1.Get the BluetoothAdapter获得蓝牙适配器 private BluetoothAdapter mBluetoothAdapter; ... // Initializes Bluetooth adapter. final BluetoothManager bluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE); mBluetoothAdapter = bluetoothManager.getAdapter();2.Enable Bluetooth打开蓝牙 // Ensures Bluetooth is available on the device and it is enabled. If not, // displays a dialog requesting user permission to enable Bluetooth. if (mBluetoothAdapter == null || !mBluetoothAdapter.isEnabled()) { Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE); startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT); }3.初始化BLE蓝牙广播(广告)(1)广播的设置
    (2)设置广播的数据
    (3)设置响应的数据
    (4)设置连接回调 private void initGATTServer() { AdvertiseSettings settings = new AdvertiseSettings.Builder() .setConnectable(true) .build(); AdvertiseData advertiseData = new AdvertiseData.Builder() .setIncludeDeviceName(true) .setIncludeTxPowerLevel(true) .build(); AdvertiseData scanResponseData = new AdvertiseData.Builder() .addServiceUuid(new ParcelUuid(UUID_SERVER)) .setIncludeTxPowerLevel(true) .build(); AdvertiseCallback callback = new AdvertiseCallback() { @Override public void onStartSuccess(AdvertiseSettings settingsInEffect) { Log.d(TAG, "BLE advertisement added successfully"); showText("1. initGATTServer success"); println("1. initGATTServer success"); initServices(getContext()); } @Override public void onStartFailure(int errorCode) { Log.e(TAG, "Failed to add BLE advertisement, reason: " + errorCode); showText("1. initGATTServer failure"); } }; BluetoothLeAdvertiser bluetoothLeAdvertiser = mBluetoothAdapter.getBluetoothLeAdvertiser(); bluetoothLeAdvertiser.startAdvertising(settings, advertiseData, scanResponseData, callback); }在被BLE设备连接后,将触发 AdvertiseCallback 的 onStartSuccess,我们在这之后,初始化GATT的服务4.初始化GATT的服务(1) 通过 mBluetoothManager.openGattServer() 获得 bluetoothGattServer(2) 添加 服务,特征,描述。这些内容要让客户端知道。 private void initServices(Context context) { bluetoothGattServer = mBluetoothManager.openGattServer(context, bluetoothGattServerCallback); BluetoothGattService service = new BluetoothGattService(UUID_SERVER, BluetoothGattService.SERVICE_TYPE_PRIMARY); //add a read characteristic. characteristicRead = new BluetoothGattCharacteristic(UUID_CHARREAD, BluetoothGattCharacteristic.PROPERTY_READ, BluetoothGattCharacteristic.PERMISSION_READ); //add a descriptor BluetoothGattDescriptor descriptor = new BluetoothGattDescriptor(UUID_DESCRIPTOR, BluetoothGattCharacteristic.PERMISSION_WRITE); characteristicRead.addDescriptor(descriptor); service.addCharacteristic(characteristicRead); //add a write characteristic. BluetoothGattCharacteristic characteristicWrite = new BluetoothGattCharacteristic(UUID_CHARWRITE, BluetoothGattCharacteristic.PROPERTY_WRITE | BluetoothGattCharacteristic.PROPERTY_READ | BluetoothGattCharacteristic.PROPERTY_NOTIFY, BluetoothGattCharacteristic.PERMISSION_WRITE); service.addCharacteristic(characteristicWrite); bluetoothGattServer.addService(service); Log.e(TAG, "2. initServices ok"); showText("2. initServices ok"); }在 openGattServer 方法中,我们需要传入个回调
    bluetoothGattServer = mBluetoothManager.openGattServer(context, bluetoothGattServerCallback);5.配置数据交互回调回调时间有:连接状态变化,收发消息,通知消息/** * 服务事件的回调 */ private BluetoothGattServerCallback bluetoothGattServerCallback = new BluetoothGattServerCallback() { /** * 1.连接状态发生变化时 * @param device * @param status * @param newState */ @Override public void onConnectionStateChange(BluetoothDevice device, int status, int newState) { Log.e(TAG, String.format("1.onConnectionStateChange:device name = %s, address = %s", device.getName(), device.getAddress())); Log.e(TAG, String.format("1.onConnectionStateChange:status = %s, newState =%s ", status, newState)); super.onConnectionStateChange(device, status, newState); } @Override public void onServiceAdded(int status, BluetoothGattService service) { super.onServiceAdded(status, service); Log.e(TAG, String.format("onServiceAdded:status = %s", status)); } @Override public void onCharacteristicReadRequest(BluetoothDevice device, int requestId, int offset, BluetoothGattCharacteristic characteristic) { Log.e(TAG, String.format("onCharacteristicReadRequest:device name = %s, address = %s", device.getName(), device.getAddress())); Log.e(TAG, String.format("onCharacteristicReadRequest:requestId = %s, offset = %s", requestId, offset)); bluetoothGattServer.sendResponse(device, requestId, BluetoothGatt.GATT_SUCCESS, offset, characteristic.getValue()); // super.onCharacteristicReadRequest(device, requestId, offset, characteristic); } /** * 3. onCharacteristicWriteRequest,接收具体的字节 * @param device * @param requestId * @param characteristic * @param preparedWrite * @param responseNeeded * @param offset * @param requestBytes */ @Override public void onCharacteristicWriteRequest(BluetoothDevice device, int requestId, BluetoothGattCharacteristic characteristic, boolean preparedWrite, boolean responseNeeded, int offset, byte[] requestBytes) { Log.e(TAG, String.format("3.onCharacteristicWriteRequest:device name = %s, address = %s", device.getName(), device.getAddress())); Log.e(TAG, String.format("3.onCharacteristicWriteRequest:requestId = %s, preparedWrite=%s, responseNeeded=%s, offset=%s, value=%s", requestId, preparedWrite, responseNeeded, offset, OutputStringUtil.toHexString(requestBytes))); bluetoothGattServer.sendResponse(device, requestId, BluetoothGatt.GATT_SUCCESS, offset, requestBytes); //4.处理响应内容 onResponseToClient(requestBytes, device, requestId, characteristic); } /** * 2.描述被写入时,在这里执行 bluetoothGattServer.sendResponse(device, requestId, BluetoothGatt.GATT_SUCCESS... 收,触发 onCharacteristicWriteRequest * @param device * @param requestId * @param descriptor * @param preparedWrite * @param responseNeeded * @param offset * @param value */ @Override public void onDescriptorWriteRequest(BluetoothDevice device, int requestId, BluetoothGattDescriptor descriptor, boolean preparedWrite, boolean responseNeeded, int offset, byte[] value) { Log.e(TAG, String.format("2.onDescriptorWriteRequest:device name = %s, address = %s", device.getName(), device.getAddress())); Log.e(TAG, String.format("2.onDescriptorWriteRequest:requestId = %s, preparedWrite = %s, responseNeeded = %s, offset = %s, value = %s,", requestId, preparedWrite, responseNeeded, offset, OutputStringUtil.toHexString(value))); // now tell the connected device that this was all successfull bluetoothGattServer.sendResponse(device, requestId, BluetoothGatt.GATT_SUCCESS, offset, value); } /** * 5.特征被读取。当回复响应成功后,客户端会读取然后触发本方法 * @param device * @param requestId * @param offset * @param descriptor */ @Override public void onDescriptorReadRequest(BluetoothDevice device, int requestId, int offset, BluetoothGattDescriptor descriptor) { Log.e(TAG, String.format("onDescriptorReadRequest:device name = %s, address = %s", device.getName(), device.getAddress())); Log.e(TAG, String.format("onDescriptorReadRequest:requestId = %s", requestId)); // super.onDescriptorReadRequest(device, requestId, offset, descriptor); bluetoothGattServer.sendResponse(device, requestId, BluetoothGatt.GATT_SUCCESS, offset, null); } @Override public void onNotificationSent(BluetoothDevice device, int status) { super.onNotificationSent(device, status); Log.e(TAG, String.format("5.onNotificationSent:device name = %s, address = %s", device.getName(), device.getAddress())); Log.e(TAG, String.format("5.onNotificationSent:status = %s", status)); } @Override public void onMtuChanged(BluetoothDevice device, int mtu) { super.onMtuChanged(device, mtu); Log.e(TAG, String.format("onMtuChanged:mtu = %s", mtu)); } @Override public void onExecuteWrite(BluetoothDevice device, int requestId, boolean execute) { super.onExecuteWrite(device, requestId, execute); Log.e(TAG, String.format("onExecuteWrite:requestId = %s", requestId)); } };6.处理来自客户端发来的数据和发送回复数据:调用 bluetoothGattServer.notifyCharacteristicChanged 方法,通知数据改变。 /** * 4.处理响应内容 * * @param reqeustBytes * @param device * @param requestId * @param characteristic */ private void onResponseToClient(byte[] reqeustBytes, BluetoothDevice device, int requestId, BluetoothGattCharacteristic characteristic) { Log.e(TAG, String.format("4.onResponseToClient:device name = %s, address = %s", device.getName(), device.getAddress())); Log.e(TAG, String.format("4.onResponseToClient:requestId = %s", requestId)); String msg = OutputStringUtil.transferForPrint(reqeustBytes); println("4.收到:" + msg); showText("4.收到:" + msg); String str = new String(reqeustBytes) + " hello>"; characteristicRead.setValue(str.getBytes()); bluetoothGattServer.notifyCharacteristicChanged(device, characteristicRead, false); println("4.响应:" + str); showText("4.响应:" + str); }交互流程:(1) 当客户端开始写入数据时: 触发回调方法 onDescriptorWriteRequest(2) 在 onDescriptorWriteRequest 方法中,执行下面的方法表示 写入成功 BluetoothGatt.GATT_SUCCESS bluetoothGattServer.sendResponse(device, requestId, BluetoothGatt.GATT_SUCCESS, offset, value); 执行 sendResponse后,会触发回调方法 onCharacteristicWriteRequest(3) 在 onCharacteristicWriteRequest方法中 public void onCharacteristicWriteRequest(BluetoothDevice device, int requestId, BluetoothGattCharacteristic characteristic, boolean preparedWrite, boolean responseNeeded, int offset, byte[] requestBytes) { 这个里可以获得 来自客户端发来的数据 requestBytes(4) 处理响应内容,我写了这个方法: onResponseToClient(requestBytes, device, requestId, characteristic); 在这个方法中,通过 bluetoothGattServer.notifyCharacteristicChanged()方法 回复数据通过日志,我们看看事件触发的顺序1.onConnectionStateChange:device name = null, address = 74:32:DE:49:3C:28 1.onConnectionStateChange:status = 0, newState =2 2.onDescriptorWriteRequest:device name = null, address = 74:32:DE:49:3C:28 2.onDescriptorWriteRequest:requestId = 1, preparedWrite = false, responseNeeded = true, offset = 0, value = [01,00,], 3.onCharacteristicWriteRequest:device name = null, address = 74:32:DE:49:3C:28 3.onCharacteristicWriteRequest:requestId = 2, preparedWrite=false, responseNeeded=false, offset=0, value=[41,54,45,30,0D,] 4.onResponseToClient:device name = null, address = 74:32:DE:49:3C:28 4.onResponseToClient:requestId = 2 4.收到:ATE0 4.响应:ATE0 hello> 5.onNotificationSent:device name = null, address = 74:32:DE:49:3C:28 5.onNotificationSent:status = 0代码托管到github:https://github.com/vir56k/bluetoothDemo 找到 bleperipheraldemo 文件夹

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