滑块移动时删除注释 - 迅速
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【中文标题】滑块移动时删除注释 - 迅速【英文标题】：Remove annotation when slider moves - swift 【发布时间】：2020-10-21 21:25:53 【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，上一次移动的注释不会消失，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？
【问题讨论】：
【参考方案1】：查看您在 removeQuake 中使用的代码会很有帮助，但在快速查看您的代码后，很有可能是该代码
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解。并且此注释不会保留在任何地方。因此，当您调用removeQuake(quake:i) 时，您不能指望i 是您使用printQuake 添加的任何注释。
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。也许它会帮助您解决您遇到的问题。
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()
【讨论】：
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