4.7

安卓蓝牙低功耗（BLE）开发详解
蓝牙低功耗（BLE）技术在物联网设备中广泛应用，安卓提供了丰富的 API 用于 BLE 开发。​

1. 权限与设备检查​
   在 AndroidManifest.xml 中添加权限：​
   ​
   ​
   ​
   ​
   ​
   在代码中检查设备是否支持 BLE：​
   ​
   BluetoothManager bluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);​
   BluetoothAdapter bluetoothAdapter = bluetoothManager.getAdapter();​
   if (bluetoothAdapter == null ||!bluetoothAdapter.isMultipleAdvertisementSupported()) {​
   // 设备不支持BLE​
   return;​
   }​
   ​
2. 扫描与连接设备​
   扫描 BLE 设备：​
   ​
   BluetoothLeScanner scanner = bluetoothAdapter.getBluetoothLeScanner();​
   ScanCallback scanCallback = new ScanCallback() {​
   @Override​
   public void onScanResult(int callbackType, ScanResult result) {​
   super.onScanResult(callbackType, result);​
   BluetoothDevice device = result.getDevice();​
   // 处理扫描到的设备​
   }​
   };​
   scanner.startScan(null, scanCallback);​
   ​
   连接设备并读取数据：​
   ​
   BluetoothGatt bluetoothGatt = device.connectGatt(this, false, new BluetoothGattCallback() {​
   @Override​
   public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {​
   if (newState == BluetoothProfile.STATE_CONNECTED) {​
   gatt.discoverServices();​
   }​
   }​
   @Override​
   public void onServicesDiscovered(BluetoothGatt gatt, int status) {​
   BluetoothGattService service = gatt.getService(UUID.fromString(SERVICE_UUID));​
   BluetoothGattCharacteristic characteristic = service.getCharacteristic(UUID.fromString(CHARACTERISTIC_UUID));​
   gatt.readCharacteristic(characteristic);​
   }​
   @Override​
   public void onCharacteristicRead(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) {​
   byte[] value = characteristic.getValue();​
   // 处理读取到的数据​
   }​
   });​