Android-低功耗蓝牙(BLE)-客户端(主机/中心设备)和服务端(从机/外围设备)

生也有涯，知也无涯。这篇文章主要讲述Android-低功耗蓝牙(BLE)-客户端(主机/中心设备)和服务端(从机/外围设备)相关的知识，希望能为你提供帮助。
一.android 低功耗蓝牙(BLE)的API简介

从Android 4.3(API 18)才支持低功耗蓝牙(Bluetooth Low Energy, BLE)的核心功能, BLE蓝牙协议是GATT协议, BLE相关类不多, 全都位于android.bluetooth包和android.bluetooth.le包的几个类: android.bluetooth. .BluetoothGattService包含多个Characteristic(属性特征值), 含有唯一的UUID作为标识 .BluetoothGattCharacteristic包含单个值和多个Descriptor, 含有唯一的UUID作为标识 .BluetoothGattDescriptor对Characteristic进行描述, 含有唯一的UUID作为标识.BluetoothGatt客户端相关 .BluetoothGattCallback客户端连接回调 .BluetoothGattServer服务端相关 .BluetoothGattServerCallback 服务端连接回调android.bluetooth.le. .AdvertiseCallback服务端的广播回调 .AdvertiseData服务端的广播数据 .AdvertiseSettings 服务端的广播设置 .BluetoothLeAdvertiser 服务端的广播.BluetoothLeScanner客户端扫描相关(Android5.0新增) .ScanCallback客户端扫描回调 .ScanFilter 客户端扫描过滤 .ScanRecord 客户端扫描结果的广播数据 .ScanResult 客户端扫描结果 .ScanSettings 客户端扫描设置BLE设备分为两种设备: 客户端(也叫主机/中心设备/Central), 服务端(也叫从机/外围设备/peripheral) 客户端的核心类是 BluetoothGatt 服务端的核心类是 BluetoothGattServer 和 BluetoothLeAdvertiser BLE数据的核心类是 BluetoothGattCharacteristic 和 BluetoothGattDescriptor

二.低功耗蓝牙(BLE)-手机同时作为BLE客户端和BLE服务端,读写Characteristic数据【Android-低功耗蓝牙(BLE)-客户端(主机/中心设备)和服务端(从机/外围设备)】完整源码: https://github.com/lifegh/Bluetooth

文章图片
bt_client.png

文章图片
bt_server.png

1.蓝牙权限

BLE权限增加了BEL支持检查，其它与上篇的经典蓝牙相同，不再写了 (1).在manifest中添加权限(2).在Activity中设置蓝牙 // 检查是否支持BLE蓝牙 if (!getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH_LE)) { Util.toast(this, "本机不支持低功耗蓝牙！"); finish(); return; }

2.BLE客户端(也叫主机/中心设备/Central)
(1).扫描BLE设备(不包含经典蓝牙)

注意: BLE设备地址是动态变化(每隔一段时间都会变化),而经典蓝牙设备是出厂就固定不变了！ BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter(); // 下面使用Android5.0新增的扫描API，扫描返回的结果更友好，比如BLE广播数据以前是byte[] scanRecord，而新API帮我们解析成ScanRecord类 // 旧API是BluetoothAdapter.startLeScan(...) final BluetoothLeScanner bluetoothLeScanner = bluetoothAdapter.getBluetoothLeScanner(); bluetoothLeScanner.startScan(mScanCallback); mHandler.postDelayed(new Runnable() { @Override public void run() { bluetoothLeScanner.stopScan(mScanCallback); //停止扫描 isScanning = false; } }, 3000); // 扫描结果Callback private final ScanCallback mScanCallback = new ScanCallback() { @Override public void onScanResult(int callbackType, ScanResult result) {、 BluetoothDevice dev = result.getDevice() 获取BLE设备信息 // result.getScanRecord() 获取BLE广播数据 } };

(2).建立连接

// 获取扫描设备，建立连接 closeConn(); BluetoothDevice dev = result.getDevice() mBluetoothGatt = dev.connectGatt(BleClientActivity.this, false, mBluetoothGattCallback); // 连接蓝牙设备// BLE中心设备连接外围设备的数量有限(大概2~7个)，在建立新连接之前必须释放旧连接资源，否则容易出现连接错误133 private void closeConn() { if (mBluetoothGatt != null) { mBluetoothGatt.disconnect(); mBluetoothGatt.close(); } }// 与服务端连接的Callback public BluetoothGattCallback mBluetoothGattCallback = new BluetoothGattCallback() { @Override public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) { BluetoothDevice dev = gatt.getDevice(); Log.i(TAG, String.format("onConnectionStateChange:%s,%s,%s,%s", dev.getName(), dev.getAddress(), status, newState)); if (status == BluetoothGatt.GATT_SUCCESS & & newState == BluetoothProfile.STATE_CONNECTED) { isConnected = true; gatt.discoverServices(); //启动服务发现 } else { isConnected = false; closeConn(); } logTv(String.format(status == 0 ? (newState == 2 ? "与[%s]连接成功" : "与[%s]连接断开") : ("与[%s]连接出错,错误码:" + status), dev)); }@Override public void onServicesDiscovered(BluetoothGatt gatt, int status) { Log.i(TAG, String.format("onServicesDiscovered:%s,%s,%s", gatt.getDevice().getName(), gatt.getDevice().getAddress(), status)); if (status == BluetoothGatt.GATT_SUCCESS) { //BLE服务发现成功 // 遍历获取BLE服务Services/Characteristics/Descriptors的全部UUID for (BluetoothGattService service : gatt.getServices()) { StringBuilder allUUIDs = new StringBuilder("UUIDs={nS=" + service.getUuid().toString()); for (BluetoothGattCharacteristic characteristic : service.getCharacteristics()) { allUUIDs.append(",nC=").append(characteristic.getUuid()); for (BluetoothGattDescriptor descriptor : characteristic.getDescriptors()) allUUIDs.append(",nD=").append(descriptor.getUuid()); } allUUIDs.append("}"); Log.i(TAG, "onServicesDiscovered:" + allUUIDs.toString()); logTv("发现服务" + allUUIDs); } } }@Override public void onCharacteristicRead(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) { UUID uuid = characteristic.getUuid(); String valueStr = new String(characteristic.getValue()); Log.i(TAG, String.format("onCharacteristicRead:%s,%s,%s,%s,%s", gatt.getDevice().getName(), gatt.getDevice().getAddress(), uuid, valueStr, status)); logTv("读取Characteristic[" + uuid + "]:n" + valueStr); }@Override public void onCharacteristicWrite(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) { UUID uuid = characteristic.getUuid(); String valueStr = new String(characteristic.getValue()); Log.i(TAG, String.format("onCharacteristicWrite:%s,%s,%s,%s,%s", gatt.getDevice().getName(), gatt.getDevice().getAddress(), uuid, valueStr, status)); logTv("写入Characteristic[" + uuid + "]:n" + valueStr); }@Override public void onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) { UUID uuid = characteristic.getUuid(); String valueStr = new String(characteristic.getValue()); Log.i(TAG, String.format("onCharacteristicChanged:%s,%s,%s,%s", gatt.getDevice().getName(), gatt.getDevice().getAddress(), uuid, valueStr)); logTv("通知Characteristic[" + uuid + "]:n" + valueStr); }@Override public void onDescriptorRead(BluetoothGatt gatt, BluetoothGattDescriptor descriptor, int status) { UUID uuid = descriptor.getUuid(); String valueStr = Arrays.toString(descriptor.getValue()); Log.i(TAG, String.format("onDescriptorRead:%s,%s,%s,%s,%s", gatt.getDevice().getName(), gatt.getDevice().getAddress(), uuid, valueStr, status)); logTv("读取Descriptor[" + uuid + "]:n" + valueStr); }@Override public void onDescriptorWrite(BluetoothGatt gatt, BluetoothGattDescriptor descriptor, int status) { UUID uuid = descriptor.getUuid(); String valueStr = Arrays.toString(descriptor.getValue()); Log.i(TAG, String.format("onDescriptorWrite:%s,%s,%s,%s,%s", gatt.getDevice().getName(), gatt.getDevice().getAddress(), uuid, valueStr, status)); logTv("写入Descriptor[" + uuid + "]:n" + valueStr); } };

(3).传输数据(读写CHARACTERISTIC和DESCRIPTOR)

注意： 1.每次读写数据最多20个字节，如果超过，只能分包 2.连续频繁读写数据容易失败，读写操作间隔最好200ms以上，或等待上次回调完成后再进行下次读写操作！ // 读取数据成功会回调-> onCharacteristicChanged() public void read(View view) { BluetoothGattService service = getGattService(BleServerActivity.UUID_SERVICE); if (service != null) { BluetoothGattCharacteristic characteristic = service.getCharacteristic(BleServerActivity.UUID_CHAR_READ_NOTIFY); //通过UUID获取可读的Characteristic mBluetoothGatt.readCharacteristic(characteristic); } }// 写入数据成功会回调-> onCharacteristicWrite() public void write(View view) { BluetoothGattService service = getGattService(BleServerActivity.UUID_SERVICE); if (service != null) { String text = mWriteET.getText().toString(); BluetoothGattCharacteristic characteristic = service.getCharacteristic(BleServerActivity.UUID_CHAR_WRITE); //通过UUID获取可写的Characteristic characteristic.setValue(text.getBytes()); //单次最多20个字节 mBluetoothGatt.writeCharacteristic(characteristic); } }// 获取Gatt服务 private BluetoothGattService getGattService(UUID uuid) { BluetoothGattService service = mBluetoothGatt.getService(uuid); if (service == null) Util.toast(this, "没有找到服务UUID=" + uuid); return service; }

(4).设置通知,实时监听CHARACTERISTIC变化

// Characteristic变化会回调-> onCharacteristicChanged() BluetoothGattService service = getGattService(BleServerActivity.UUID_SERVICE); if (service != null) { // 设置Characteristic通知 BluetoothGattCharacteristic characteristic = service.getCharacteristic(BleServerActivity.UUID_CHAR_READ_NOTIFY); //通过UUID获取可通知的Characteristic mBluetoothGatt.setCharacteristicNotification(characteristic, true); // 向Characteristic的Descriptor属性写入通知开关，使蓝牙设备主动向手机发送数据 BluetoothGattDescriptor descriptor = characteristic.getDescriptor(BleServerActivity.UUID_DESC_NOTITY); // descriptor.setValue(BluetoothGattDescriptor.ENABLE_INDICATION_VALUE); //和通知类似,但服务端不主动发数据,只指示客户端读取数据 descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE); mBluetoothGatt.writeDescriptor(descriptor); }

3.BLE服务端(也叫从机/外围设备/peripheral)

public static final UUID UUID_SERVICE = UUID.fromString("10000000-0000-0000-0000-000000000000"); //自定义UUID public static final UUID UUID_CHAR_READ_NOTIFY = UUID.fromString("11000000-0000-0000-0000-000000000000"); public static final UUID UUID_DESC_NOTITY = UUID.fromString("11100000-0000-0000-0000-000000000000"); public static final UUID UUID_CHAR_WRITE = UUID.fromString("12000000-0000-0000-0000-000000000000"); private BluetoothLeAdvertiser mBluetoothLeAdvertiser; // BLE广播 private BluetoothGattServer mBluetoothGattServer; // BLE服务端@Override protected void onCreate(Bundle savedInstanceState) { ...... BluetoothManager bluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE); // BluetoothAdapter bluetoothAdapter = bluetoothManager.getAdapter(); BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter(); // ============启动BLE蓝牙广播(广告) ================================================================================= //广播设置(必须) AdvertiseSettings settings = new AdvertiseSettings.Builder() .setAdvertiseMode(AdvertiseSettings.ADVERTISE_MODE_LOW_LATENCY) //广播模式: 低功耗,平衡,低延迟 .setTxPowerLevel(AdvertiseSettings.ADVERTISE_TX_POWER_HIGH) //发射功率级别: 极低,低,中,高 .setConnectable(true) //能否连接,广播分为可连接广播和不可连接广播 .build(); //广播数据(必须，广播启动就会发送) AdvertiseData advertiseData = https://www.songbingjia.com/android/new AdvertiseData.Builder() .setIncludeDeviceName(true) //包含蓝牙名称 .setIncludeTxPowerLevel(true) //包含发射功率级别 .addManufacturerData(1, new byte[]{23, 33}) //设备厂商数据，自定义 .build(); //扫描响应数据(可选，当客户端扫描时才发送) AdvertiseData scanResponse = new AdvertiseData.Builder() .addManufacturerData(2, new byte[]{66, 66}) //设备厂商数据，自定义 .addServiceUuid(new ParcelUuid(UUID_SERVICE)) //服务UUID //.addServiceData(new ParcelUuid(UUID_SERVICE), new byte[]{2}) //服务数据，自定义 .build(); mBluetoothLeAdvertiser = bluetoothAdapter.getBluetoothLeAdvertiser(); mBluetoothLeAdvertiser.startAdvertising(settings, advertiseData, scanResponse, mAdvertiseCallback); // 注意：必须要开启可连接的BLE广播，其它设备才能发现并连接BLE服务端! // =============启动BLE蓝牙服务端===================================================================================== BluetoothGattService service = new BluetoothGattService(UUID_SERVICE, BluetoothGattService.SERVICE_TYPE_PRIMARY); //添加可读+通知characteristic BluetoothGattCharacteristic characteristicRead = new BluetoothGattCharacteristic(UUID_CHAR_READ_NOTIFY, BluetoothGattCharacteristic.PROPERTY_READ | BluetoothGattCharacteristic.PROPERTY_NOTIFY, BluetoothGattCharacteristic.PERMISSION_READ); characteristicRead.addDescriptor(new BluetoothGattDescriptor(UUID_DESC_NOTITY, BluetoothGattCharacteristic.PERMISSION_WRITE)); service.addCharacteristic(characteristicRead); //添加可写characteristic BluetoothGattCharacteristic characteristicWrite = new BluetoothGattCharacteristic(UUID_CHAR_WRITE, BluetoothGattCharacteristic.PROPERTY_WRITE, BluetoothGattCharacteristic.PERMISSION_WRITE); service.addCharacteristic(characteristicWrite); if (bluetoothManager != null) mBluetoothGattServer = bluetoothManager.openGattServer(this, mBluetoothGattServerCallback); mBluetoothGattServer.addService(service); }// BLE广播Callback private AdvertiseCallback mAdvertiseCallback = new AdvertiseCallback() { @Override public void onStartSuccess(AdvertiseSettings settingsInEffect) { logTv("BLE广播开启成功"); }@Override public void onStartFailure(int errorCode) { logTv("BLE广播开启失败,错误码:" + errorCode); } }; // BLE服务端Callback private BluetoothGattServerCallback mBluetoothGattServerCallback = new BluetoothGattServerCallback() { @Override public void onConnectionStateChange(BluetoothDevice device, int status, int newState) { Log.i(TAG, String.format("onConnectionStateChange:%s,%s,%s,%s", device.getName(), device.getAddress(), status, newState)); logTv(String.format(status == 0 ? (newState == 2 ? "与[%s]连接成功" : "与[%s]连接断开") : ("与[%s]连接出错,错误码:" + status), device)); }@Override public void onServiceAdded(int status, BluetoothGattService service) { Log.i(TAG, String.format("onServiceAdded:%s,%s", status, service.getUuid())); logTv(String.format(status == 0 ? "添加服务[%s]成功" : "添加服务[%s]失败,错误码:" + status, service.getUuid())); }@Override public void onCharacteristicReadRequest(BluetoothDevice device, int requestId, int offset, BluetoothGattCharacteristic characteristic) { Log.i(TAG, String.format("onCharacteristicReadRequest:%s,%s,%s,%s,%s", device.getName(), device.getAddress(), requestId, offset, characteristic.getUuid())); String response = "CHAR_" + (int) (Math.random() * 100); //模拟数据 mBluetoothGattServer.sendResponse(device, requestId, BluetoothGatt.GATT_SUCCESS, offset, response.getBytes()); // 响应客户端 logTv("客户端读取Characteristic[" + characteristic.getUuid() + "]:n" + response); }@Override public void onCharacteristicWriteRequest(BluetoothDevice device, int requestId, BluetoothGattCharacteristic characteristic, boolean preparedWrite, boolean responseNeeded, int offset, byte[] requestBytes) { // 获取客户端发过来的数据 String requestStr = new String(requestBytes); Log.i(TAG, String.format("onCharacteristicWriteRequest:%s,%s,%s,%s,%s,%s,%s,%s", device.getName(), device.getAddress(), requestId, characteristic.getUuid(), preparedWrite, responseNeeded, offset, requestStr)); mBluetoothGattServer.sendResponse(device, requestId, BluetoothGatt.GATT_SUCCESS, offset, requestBytes); // 响应客户端 logTv("客户端写入Characteristic[" + characteristic.getUuid() + "]:n" + requestStr); }@Override public void onDescriptorReadRequest(BluetoothDevice device, int requestId, int offset, BluetoothGattDescriptor descriptor) { Log.i(TAG, String.format("onDescriptorReadRequest:%s,%s,%s,%s,%s", device.getName(), device.getAddress(), requestId, offset, descriptor.getUuid())); String response = "DESC_" + (int) (Math.random() * 100); //模拟数据 mBluetoothGattServer.sendResponse(device, requestId, BluetoothGatt.GATT_SUCCESS, offset, response.getBytes()); // 响应客户端 logTv("客户端读取Descriptor[" + descriptor.getUuid() + "]:n" + response); }@Override public void onDescriptorWriteRequest(final BluetoothDevice device, int requestId, BluetoothGattDescriptor descriptor, boolean preparedWrite, boolean responseNeeded, int offset, byte[] value) { // 获取客户端发过来的数据 String valueStr = Arrays.toString(value); Log.i(TAG, String.format("onDescriptorWriteRequest:%s,%s,%s,%s,%s,%s,%s,%s", device.getName(), device.getAddress(), requestId, descriptor.getUuid(), preparedWrite, responseNeeded, offset, valueStr)); mBluetoothGattServer.sendResponse(device, requestId, BluetoothGatt.GATT_SUCCESS, offset, value); // 响应客户端 logTv("客户端写入Descriptor[" + descriptor.getUuid() + "]:n" + valueStr); // 简单模拟通知客户端Characteristic变化 if (Arrays.toString(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE).equals(valueStr)) { //是否开启通知 final BluetoothGattCharacteristic characteristic = descriptor.getCharacteristic(); new Thread(new Runnable() { @Override public void run() { for (int i = 0; i < 5; i++) { SystemClock.sleep(3000); String response = "CHAR_" + (int) (Math.random() * 100); //模拟数据 characteristic.setValue(response); mBluetoothGattServer.notifyCharacteristicChanged(device, characteristic, false); logTv("通知客户端改变Characteristic[" + characteristic.getUuid() + "]:n" + response); } } }).start(); } }@Override public void onExecuteWrite(BluetoothDevice device, int requestId, boolean execute) { Log.i(TAG, String.format("onExecuteWrite:%s,%s,%s,%s", device.getName(), device.getAddress(), requestId, execute)); }@Override public void onNotificationSent(BluetoothDevice device, int status) { Log.i(TAG, String.format("onNotificationSent:%s,%s,%s", device.getName(), device.getAddress(), status)); }@Override public void onMtuChanged(BluetoothDevice device, int mtu) { Log.i(TAG, String.format("onMtuChanged:%s,%s,%s", device.getName(), device.getAddress(), mtu)); } };

简书: https://www.jianshu.com/p/8ac31a5070d4
CSDN: https://blog.csdn.net/qq_32115439/article/details/80643906
GitHub博客: http://lioil.win/2018/06/10/Android-BLE.html
Coding博客: http://c.lioil.win/2018/06/10/Android-BLE.html