Flutter 错误：'BluetoothDevice' 类型的值？ 不能分配给“BluetoothDevice”类型的变量

Question

Flutter Error: A value of type 'BluetoothDevice?' can't be assigned to a variable of type 'BluetoothDevice'. Try changing the type of the variable, or casting the right-hand type to 'BluetoothDevice'.

void initState() {
    super.initState();
    // Start scanning for devices
    flutterBlue.startScan(timeout: Duration(seconds: 4));
    // Listen for scan results
    flutterBlue.scanResults.listen((results) {
      // Find the heart rate device
      device = results.firstWhere((r) => r.device.name == 'Heart Rate',
                orElse: () => null)?.device;

      if (device != null) {
        flutterBlue.stopScan();
        connectToDevice();
      }
    });
  }

Answer 1

Try this:

void initState() {
    super.initState();
    // Start scanning for devices
    flutterBlue.startScan(timeout: Duration(seconds: 4));
    // Listen for scan results
    flutterBlue.scanResults.listen((results) {
    if(results != null) {
       // Find the heart rate device
      device = results.firstWhere((r) => r.device.name == 'Heart Rate',
                orElse: () => null)!.device;

     }
      if (device != null) {
        flutterBlue.stopScan();
        connectToDevice();
      }
    });
  }