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swift - 滑块移动时删除注释 - 迅速

问题描述

我遇到了无法解决的注释问题。当您单击 UIButton 时，@IBAction pressPlay 函数会启动，这会导致我的地图上的滑块开始移动。滑块的最大值为 0，最小值为 -31，初始值为 0，只有在拇指到位时才开始移动！= 从 0 开始，每 1 秒移动一次。这可以正确移动滑块。

@IBAction func pressPlay(_ sender: Any)
    {
        let calendar2 = Calendar.current
        let today = Date()
        var cnt = Int(sliderTime.value)
        let play = UIImage(named: "play")
        let pause = UIImage(named: "pause")
        let format = DateFormatter()
        playButton.setImage(play, for: .normal)
        if control == true && Int(sliderTime.value) < 0
        { //mette in play
            control = false
            playButton.setImage(pause, for: .normal)
            //removeSeismometers = true
            if Int(sliderTime.value) < 0
            {
                timer = Timer.scheduledTimer(withTimeInterval: 1,repeats: true)
                { [self]t in //ogni secondo questo timer cambia il valore dell'alpha del pin che sta vibrando
                    
                    if cnt < 0
                    {
                        cnt = Int(self.sliderTime.value)
                        self.sliderTime.value += 1
                        let newDate2 = calendar2.date(byAdding: .day, value: Int(self.sliderTime.value), to:today)! //sottraggo alla data attuale il vlaore dello slider per tornare indietro nel tempo
                        format.dateStyle = .medium // "MM/GG/AAAA"
                        self.labelTime.text = "\(format.string(from: newDate2))"
                        appo += 1
                        for i in mapEqAnnotation{
                            let str: String = i.eq.eventTime
                            let index = str.index(str.endIndex, offsetBy: -9)
                            let mySubstring = str[..<index]
                            nuovaData = calendario.date(byAdding: .day, value: Int(sliderTime.value), to:dataCorrente)!
                            let format = DateFormatter()
                            format.dateFormat = "yyyy-MM-dd"
                            let dataCntr = "\(format.string(from: nuovaData))"
                            if mySubstring == dataCntr{
                                printQuake(quake: i)
                            }else{
                                removeQuake(quake:i)
                            }
                        }
                        //printQuake(sliderValue: appo)
                    }else if cnt == 0{
                        //removeSeismometers = false
                        playButton.setImage(play, for: .normal)
                        timer!.invalidate()
                    }
                }
            }
        }else if control == false && Int(sliderTime.value) < 0 {
            playButton.setImage(play, for: .normal)
            control = true
            timer!.invalidate()
        }
    }

我的问题是，当您单击 UIButton 时，滑块每秒钟都必须移动，并且每秒钟都必须向地图添加注释，并在您再次移动滑块时立即将其删除。一切正常，除了当滑块滚动时，上一步的注释不会消失，而是保留在地图上

    func printQuake(quake: MapEarthquakeAnnotation){
        let q = MapEarthquakeAnnotation(eq:quake.eq)
        mapView.addAnnotation(q)
    }

    func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView?
    {
        if annotation is MapEarthquakeAnnotation{
            annotazioni.append(annotation)
            let EQAnnotation = annotation as! MapEarthquakeAnnotation
            var view: MKPinAnnotationView
            view = MKPinAnnotationView(annotation: annotation, reuseIdentifier: EQAnnotation.identifier)
            view.canShowCallout = true
            view.pinTintColor = UIColor.brown
            return view
            
        }else if (annotation is MapSeismometerAnnotation) {
            if let annotation = annotation as? MapSeismometerAnnotation
            {
                var view: MKPinAnnotationView
                view = MKPinAnnotationView(annotation: annotation, reuseIdentifier: annotation.identifier)
                view.canShowCallout = true
                view.pinTintColor = UIColor.green
                view.image = UIImage(named: "pin-verde")
                return view
            }
            return nil
        }
        return nil
    }

你能给我一些建议吗？

标签： swiftmkmapviewuislidermkannotationmkpinannotationview

解决方案

查看您使用的代码会很有帮助，removeQuake但在快速查看您的代码后，很可能候选者就是代码

func printQuake(quake: MapEarthquakeAnnotation){
    let q = MapEarthquakeAnnotation(eq:quake.eq)
    mapView.addAnnotation(q)
}

每次调用此方法时，您都会在此处创建一个新注释。并且此注释不会保留在任何地方。因此，当您打电话时，removeQuake(quake:i)您不能指望这i是您使用添加的任何注释printQuake。

我不确定为什么要构建此代码，但您可能需要做的就是将此方法更改为

func printQuake(quake: MapEarthquakeAnnotation){
    mapView.addAnnotation(quake)
}

一般来说，您的代码有点难以阅读。您应该研究使用 Swift 的更现代的方法，并且应该尝试拆分部分代码，以便它们更易于阅读和维护。非英语语言也不是很有帮助。

我试图拆除并重建您的代码。并非所有东西都在那里，我不确定它是否符合您的要求。但还是请检查一下。也许它会帮助你解决你遇到的问题。

import UIKit
import MapKit

class ViewController: UIViewController {
    
    @IBOutlet private var mapView: MKMapView!
    @IBOutlet private var sliderTime: UISlider!
    @IBOutlet private var playButton: UIButton!
    @IBOutlet private var labelTime: UILabel!

    private var timer: Timer?
    private var earthquakeAnnotations: [MapEarthquakeAnnotation] = []
    
    private var dayOffset: Int = -30 {
        didSet {
            refresh()
        }
    }
    
    private var isPlaying: Bool = false {
        didSet {
            playButton.setImage(isPlaying ? UIImage(named: "play") : UIImage(named: "pause"), for: .normal)
        }
    }
    
    private func refresh() {
        let beginningOfToday: Date = Calendar.autoupdatingCurrent.date(from: Calendar.autoupdatingCurrent.dateComponents([.year, .month, .day], from: Date()))!
        let presentedDay = Calendar.autoupdatingCurrent.date(byAdding: .day, value: dayOffset, to: beginningOfToday)!
        refreshSlider()
        refreshTimeLabel(date: presentedDay)
        refreshAnnotations(date: presentedDay)
    }
    
    private func refreshSlider() {
        sliderTime.value = Float(dayOffset)
    }
    
    private func refreshTimeLabel(date: Date) {
        labelTime.text = {
            let formatter = DateFormatter()
            formatter.dateStyle = .medium
            return formatter.string(from: date)
        }()
    }
    
    private func refreshAnnotations(date: Date) {
        earthquakeAnnotations.forEach { annotation in
            if annotation.eq.date == date {
                if !mapView.annotations.contains(where: { $0 === annotation }) {
                    mapView.addAnnotation(annotation)
                }
            } else {
                if mapView.annotations.contains(where: { $0 === annotation }) {
                    mapView.removeAnnotation(annotation)
                }
            }
        }
    }
    
    private func stopPlaying() {
        timer?.invalidate()
        timer = nil
        isPlaying = false
    }
    
    private func startPlaying() {
        if dayOffset < 0 {
            isPlaying = true
            timer?.invalidate() // Just in case
            timer = Timer.scheduledTimer(withTimeInterval: 1.0, repeats: true, block: { [weak self] timer in
                guard let self = self else {
                    timer.invalidate()
                    return
                }
                
                if self.dayOffset < 0 {
                    self.dayOffset += 1
                } else {
                    self.stopPlaying()
                }
            })
        } else {
            // Already at the end. Should restart?
        }
    }
    
    @IBAction func pressPausePlay(_ sender: Any) {
        if isPlaying {
            stopPlaying()
        } else {
            startPlaying()
        }
    }
    
}

// MARK: - MKMapViewDelegate

extension ViewController: MKMapViewDelegate {
    
    func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? {
        if let annotation = annotation as? MapEarthquakeAnnotation {
            let view: MKPinAnnotationView = MKPinAnnotationView(annotation: annotation, reuseIdentifier: annotation.identifier)
            view.canShowCallout = true
            view.pinTintColor = UIColor.brown
            return view
        } else if let annotation = annotation as? MapSeismometerAnnotation {
            let view: MKPinAnnotationView = MKPinAnnotationView(annotation: annotation, reuseIdentifier: annotation.identifier)
            view.canShowCallout = true
            view.pinTintColor = UIColor.green
            view.image = UIImage(named: "pin-verde")
            return view
        } else {
            return nil
        }
    }
    
}

// MARK: - MapEarthquakeAnnotation

private extension ViewController {
    
    class MapEarthquakeAnnotation: NSObject, MKAnnotation {
        var identifier: String { "MapEarthquakeAnnotationID" }
        
        let coordinate: CLLocationCoordinate2D
        let eq: Earthquake
        
        init(earthquake: Earthquake, coordinate: CLLocationCoordinate2D) { self.eq = earthquake; self.coordinate = coordinate }
    }
    
}

// MARK: - MapSeismometerAnnotation

private extension ViewController {
    
    class MapSeismometerAnnotation: NSObject, MKAnnotation {
        var identifier: String { "MapSeismometerAnnotationID" }
        
        let coordinate: CLLocationCoordinate2D
        
        init(coordinate: CLLocationCoordinate2D) { self.coordinate = coordinate }
    }
    
}

// MARK: - Earthquake

private extension ViewController {
    
    struct Earthquake {
        let eventTime: String
        
        var date: Date {
            let index = eventTime.index(eventTime.endIndex, offsetBy: -9)
            let format = DateFormatter()
            format.dateFormat = "yyyy-MM-dd"
            return format.date(from: String(eventTime[..<index])) ?? Date()
        }
    }
    
}

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