我如何使用 Flutter 中的 firstWhere 导航到另一个屏幕

Question

我在 Flutter 应用程序中使用这段代码在满足来自流的条件后导航到另一个屏幕：

void initState() {
    isReady = false;
    connectToDevice();
   
    stream?.map((value) {
      final currentVal = value.toString();
      final currentParsedVal = int.parse(
        currentVal.substring(1, currentVal.length - 1),
        onError: (source) => -1,
      );
      print("String data $currentParsedVal");
      Seziurealert();

    })?.firstWhere((value) => value == 2);
  }

而这是导航到另一个屏幕的 SeizureAlert 函数：

Seziurealert() {
    Navigator.pushAndRemoveUntil(
      context,
      MaterialPageRoute(
        builder: (context) {
          return TriggeringAlert(device: widget.device);
        },
      ),
      (route) => false,
    );
  }
}

Stream 正在使用服务从 BLE 设备获取值：

// BLE
  final String SERVICE_UUID = "0365a300-8d69-4066-80c7-554298a6ec5e";
  final String CHARACTERISTIC_UUID = "cf01c075-cb75-4dea-819e-2a79dd466bcb";
  bool isReady;
  Stream<List<int>> stream;
  List<int> lastValue;

  connectToDevice() async {
    // await widget.device.connect();
    discoverServices();
  }

  discoverServices() async {
    List<BluetoothService> services = await widget.device.discoverServices();
    services.forEach((service) {
      if (service.uuid.toString() == SERVICE_UUID) {
        service.characteristics.forEach((characteristic) {
          if (characteristic.uuid.toString() == CHARACTERISTIC_UUID) {
            characteristic.setNotifyValue(!characteristic.isNotifying);
            stream = characteristic.value;
            print(stream);
            lastValue = characteristic.lastValue;
            print(lastValue);

            // setState(() {
            //   isReady = true;
            // });
          }
        });
      }
    });
  }

我不明白它是否在控制台上显示了值，那么为什么它没有导航到另一个屏幕？

请帮助我，因为我是 Flutter 的新手