Question

我正在尝试使用带textField的警报控制器，使用mapView作为标题创建textField注释。我可以打印我创建的所有常量，但注释不起作用。当我在alertAction之外使用注释代码时，它工作正常，但我无法获得textField输入。我究竟做错了什么？

override func viewDidLoad() {
    super.viewDidLoad()

    let uilpgr = UILongPressGestureRecognizer(target: self, action: #selector(ViewController.longpress(gestureRecognizer:)))
    uilpgr.minimumPressDuration = 2
    map.addGestureRecognizer(uilpgr)

}

func longpress(gestureRecognizer: UIGestureRecognizer) {

    let alert = UIAlertController(title: "New Place", message: "Enter a name", preferredStyle: UIAlertControllerStyle.alert)

    alert.addTextField { (textField: UITextField) in
        textField.placeholder = "Name"
    }

    let okAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.default) { (UIAlertAction) in

        if let tempPlace = alert.textFields?[0].text {
            let place = tempPlace
            let touchpoint = gestureRecognizer.location(in: self.map)
            let coordinate = self.map.convert(touchpoint, toCoordinateFrom: self.map)
            let annotation = MKPointAnnotation()
            let latitude = coordinate.latitude
            let longitude = coordinate.longitude

            annotation.title = place
            annotation.subtitle = "Lat " + (String(format: "%.2f", latitude) + " Lon " + String(format: "%.2f", longitude))
            annotation.coordinate = coordinate
            self.map.addAnnotation(annotation)
        }


    }

    let cancelAction = UIAlertAction(title: "Cancel", style: UIAlertActionStyle.cancel) { (UIAlertAction) in

    }


    alert.addAction(okAction)
    alert.addAction(cancelAction)

    present(alert, animated: true, completion: nil)

}

Answer 1

只需在UIAlertController演示之前存储触摸点并在UIAlterAction中使用它，因为当长按时警报弹出/存在时，它无法保存/获取触点，为什么UIAlterAction内的触点始终为0,0。

func longpress(gestureRecognizer: UIGestureRecognizer) {

let touchpointtemp = gestureRecognizer.location(in: self.map_home)

let alert = UIAlertController(title: "New Place", message: "Enter a name", preferredStyle: UIAlertControllerStyle.alert)

    alert.addTextField { (textField: UITextField) in
        textField.placeholder = "Name"
    }

    let okAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.default) { (UIAlertAction) in

        if let tempPlace = alert.textFields?[0].text {
            let place = tempPlace
            let touchpoint = touchpointtemp
            let coordinate = self.map_home.convert(touchpoint, toCoordinateFrom: self.map_home)

            print(coordinate)
            let annotation = MKPointAnnotation()
            let latitude = coordinate.latitude
            let longitude = coordinate.longitude

            annotation.title = place
            annotation.subtitle = "Lat " + (String(format: "%.2f", latitude) + " Lon " + String(format: "%.2f", longitude))
            annotation.coordinate = coordinate
            self.map_home.addAnnotation(annotation)
        }


    }

    let cancelAction = UIAlertAction(title: "Cancel", style: UIAlertActionStyle.cancel) { (UIAlertAction) in

    }


    alert.addAction(okAction)
    alert.addAction(cancelAction)

    present(alert, animated: true, completion: nil)

}

Swift使用AlertController在mapView上添加注释

1 个答案: