通过反射调用判断蓝牙是否已连接
Method isConnectedMethod = BluetoothDevice.class.getDeclaredMethod("isConnected", (Class[]) null);
isConnectedMethod.setAccessible(true);
boolean isConnected = (boolean) isConnectedMethod.invoke(bluetoothDevice, (Object[]) null);
Method isConnectedMethod = BluetoothDevice.class.getDeclaredMethod("isConnected", (Class[]) null);
isConnectedMethod.setAccessible(true);
boolean isConnected = (boolean) isConnectedMethod.invoke(bluetoothDevice, (Object[]) null);