使用未解决的标识符“showAlert”斯威夫特

Question

我在斯威夫特新的，我堆放着每次回到我的时候这段代码和“对用户使用未解决的标识符‘showAlert’的输入区域和用户出口区域：

func setupData() { 
     // 1. check if system can monitor regions 
     if CLLocationManager.isMonitoringAvailable(for: CLCircularRegion.self) { 

      // 2. region data 
      let title = "Primo punto" 
      let coordinate = CLLocationCoordinate2DMake(38.121973, 13.360855) 
      let regionRadius = 300.0 

      // 3. setup region 
      let region = CLCircularRegion(center: CLLocationCoordinate2D(latitude: coordinate.latitude, 
                     longitude: coordinate.longitude), radius: regionRadius, identifier: title) 
      locationManager.startMonitoring(for: region) 

      // 4. setup annotation 
      let restaurantAnnotation = MKPointAnnotation() 
      restaurantAnnotation.coordinate = coordinate; 
      restaurantAnnotation.title = "\(title)"; 
      mapView.addAnnotation(restaurantAnnotation) 

      // 5. setup circle 
      let circle = MKCircle(center: coordinate, radius: regionRadius) 
      mapView.add(circle) 
     } 
     else { 
      print("System can't track regions") 
     } 
    } 

    // 6. draw circle 
    func mapView(mapView: MKMapView, rendererForOverlay overlay: MKOverlay) -> MKOverlayRenderer { 
     let circleRenderer = MKCircleRenderer(overlay: overlay) 
     circleRenderer.strokeColor = UIColor.red 
     circleRenderer.lineWidth = 1.0 
     return circleRenderer 
    } 

    // 1. user enter region 
    func locationManager(manager: CLLocationManager, didEnterRegion region: CLRegion) { 
     showAlert("enter \(region.identifier)") 
    } 

    // 2. user exit region 
    @nonobjc func locationManager(manager: CLLocationManager, didExitRegion region: CLRegion) { 
     showAlert("exit \(region.identifier)") 
    } 
} 

Answer 1

我不知道，如果你有一个'showAlert（）函数，但如果你想提醒用户，那么你可以做这样的：

//Create alert 
let alert = UIAlertController(title: "Alert", message: "Message", preferredStyle: UIAlertControllerStyle.alert) 

// Add action buttons to the alert 
alert.addAction(UIAlertAction(title: "Click", style: UIAlertActionStyle.default, handler: nil)) 

// Present the alert to the view 
self.present(alert, animated: true, completion: nil) 

，如果你想将其作为一个函数，然后创建一个名为show alerts的函数，并将自己的参数添加到该函数中，如下所示：

func showAlert(Title: String, Message: String) { 
    let alert = UIAlertController(title: Title, message: Message, preferredStyle: UIAlertControllerStyle.alert) 
    alert.addAction(UIAlertAction(title: "Click", style: UIAlertActionStyle.default, handler: nil)) 
    self.present(alert, animated: true, completion: nil) 
}