位置访问是目前我正在建设的应用程序所需要的。我已经开发了一个警报显示在位置上时，用户没有在位置上。我的代码正确运行时，我去的页面。但弹出警报消息不显示时，我去设置页面，并回到上一页没有在位置上。我怎么能显示警报消息，直到用户在位置上？这是我的代码。

componentDidMount() {
    ScaleModule.initBluetoothManager();
    // this.optionsDropDown.show()
    this.setState({
      netQuantity: this.props.route.params.data.quantity,
      // noOfPackages: this.props.route.params.noOfPackages,
      // packageList: this.props.route.params.packageList
    });
    // this.getList()
    // console.log(this.props.user)
    // this.groupBy()
    Geolocation.getCurrentPosition(
        (position) => {
          console.log('Location services are enabled.',position);
        },
        (error) => {
          switch (error.code) {
            case 1:
              console.log('Location services are disabled.');
              this.showLocationAlert();
              break;
            case 2:
              console.log('Network connection is unavailable.');
              this.showLocationAlert();
              break;
            case 3:
              console.log('Location request timed out.');
              this.showLocationAlert();
              break;
            default:
              console.log('An unknown error occurred.');
              this.showLocationAlert();
          }
        },
        { enableHighAccuracy: true, timeout: 15000, maximumAge: 10000 },
      );
  }
  
  showLocationAlert = () => {
    Alert.alert(
      'Location Required',
      'Please enable location services to continue.',
      [
        {text: 'Open Settings', onPress: () => DeviceSettings.open()},
      ]
    );
  };