如何解决SwiftUI:保存MapKit注释数据以传递到另一个视图
我正在努力保存MapKit注释数据(例如名称,地址,坐标等),然后将其传递回具有链接到地图视图的视图。我可以使用didSelect选择注释并将所需的数据打印到终端,但是我不知道如何将其传递回去。我一直在尝试使用Observedobject,但出现一条错误消息:属性'self.contentData'未在隐式生成的super.init调用中初始化。
import SwiftUI
import MapKit
//MARK:- COORDINATOR
class Coordinator: NSObject,MKMapViewDelegate {
//@Observedobject var contentData: ContentData // << deleted based on answer
var control: MapUIView
var contentData: ContentData // << added based on answer
init(_ control: MapUIView) {
self.control = control
self.contentData = control.contentData // << added based on answer
}
func mapView(_ mapView: MKMapView,didAdd views: [MKAnnotationView]) {
if let annotationView = views.first {
if let annotation = annotationView.annotation {
if annotation is MKUserLocation {
let region = MKCoordinateRegion(center: annotation.coordinate,latitudinalMeters: 8000,longitudinalMeters: 8000)
mapView.setRegion(region,animated: true)
}
}
}
}
func selectAnnotation(_ annotation: MKAnnotation,animated: Bool) {
}
func mapView(_ mapView: MKMapView,didSelect view: MKAnnotationView) {
if mapView.selectedAnnotations.count > 0 {
if let selectedPinName = mapView.selectedAnnotations[0].title {
print("\(selectedPinName!)")
}
}
let region = MKCoordinateRegion(center: view.annotation!.coordinate,span: mapView.region.span)
mapView.setRegion(region,animated: true)
contentData.selectedLocationName = (mapView.selectedAnnotations[0].title as? String)!
}
}
//MARK:- LOCATION MANAGER
class LocationManager: NSObject,ObservableObject {
private let locationManager = CLLocationManager()
@Published var location: CLLocation? = nil
override init() {
super.init()
self.locationManager.delegate = self
self.locationManager.desiredAccuracy = kCLLocationAccuracyBest
self.locationManager.distanceFilter = kCLheadingFilterNone
self.locationManager.requestWhenInUseAuthorization()
self.locationManager.startUpdatingLocation()
}
}
extension LocationManager: CLLocationManagerDelegate {
func locationManager(_ manager: CLLocationManager,didChangeAuthorization status: CLAuthorizationStatus) {
print(status)
}
func locationManager(_ manager: CLLocationManager,didUpdateLocations locations: [CLLocation]) {
guard let location = locations.last else {
return
}
self.location = location
}
}
//MARK:- LANDMARK ANNOTATION
final class LandmarkAnnotation: NSObject,MKAnnotation {
let title: String?
let subtitle: String?
let coordinate: CLLocationCoordinate2D
init(landmark: Landmark) {
self.title = landmark.name
self.subtitle = landmark.title
self.coordinate = landmark.coordinate
}
}
//MARK:- LANDMARK
struct Landmark {
let placemark: MKPlacemark
var id: UUID {
return UUID()
}
var name: String {
self.placemark.name ?? ""
}
var title: String {
self.placemark.title ?? ""
}
var coordinate: CLLocationCoordinate2D {
self.placemark.coordinate
}
}
//MARK:- VIEW
struct MapView: View {
@Observedobject var locationManager = LocationManager()
@State private var landmarks: [Landmark] = [Landmark]()
@State private var search: String = ""
@State private var tapped: Bool = false
@State private var showCancelButton: Bool = false
@Observedobject var contentData: ContentData
private func getNearByLandmarks() {
let request = MKLocalSearch.Request()
request.naturalLanguageQuery = search
let search = MKLocalSearch(request: request)
search.start { (response,error) in
if let response = response {
let mapItems = response.mapItems
self.landmarks = mapItems.map {
Landmark(placemark: $0.placemark)
}
}
}
}
var body: some View {
ZStack(alignment: .top) {
MapUIView(contentData: contentData,landmarks: landmarks)
HStack {
HStack {
Image(systemName: "magnifyingglass")
TextField("Search",text: $search,onEditingChanged: { _ in
self.showCancelButton = true
self.getNearByLandmarks()
}).foregroundColor(.primary)
Button(action: {
self.search = ""
}) {
Image(systemName: "xmark.circle.fill").opacity(search == "" ? 0 : 1)
}
}
.padding(EdgeInsets(top: 8,leading: 6,bottom: 8,trailing: 6))
.foregroundColor(.secondary)
.background(Color(.secondarySystemBackground))
.cornerRadius(10.0)
}
.padding(EdgeInsets(top: 10,leading: 0,bottom: 1,trailing: 0))
.padding(.horizontal)
}
}
}
//MARK:- MAPUIVIEW
struct MapUIView: UIViewRepresentable {
@Observedobject var contentData: ContentData
let landmarks: [Landmark]
func makeUIView(context: Context) -> MKMapView {
let map = MKMapView()
map.showsUserLocation = true
map.delegate = context.coordinator
return map
}
func makeCoordinator() -> Coordinator {
Coordinator(self)
}
func updateUIView(_ uiView: MKMapView,context: UIViewRepresentableContext<MapUIView>) {
updateAnnotations(from: uiView)
}
func updateAnnotations(from mapView: MKMapView) {
mapView.removeAnnotations(mapView.annotations)
let annotations = self.landmarks.map(LandmarkAnnotation.init)
mapView.addAnnotations(annotations)
}
}
struct MapView_Previews: PreviewProvider {
static var previews: some View {
MapView(contentData: ContentData())
}
}
调用地图视图:
NavigationLink(destination: MapView(contentData: contentData).edgesIgnoringSafeArea(.bottom),tag: 1,selection: $tag)
任何帮助将不胜感激。提前非常感谢。
编辑----------------------
在实施建议的更改之前和之后添加了注释行为的屏幕快照,以允许将注释数据与ObservableObject一起传递回先前的swiftui视图。
解决方法
这是固定的部分
class Coordinator: NSObject,MKMapViewDelegate {
var contentData: ContentData // << here !!
var control: MapUIView
init(_ control: MapUIView) {
self.control = control
self.contentData = control.contentData // << here !!
}
// ... other code
}
注意:@ObservedObject
设计为可在SwiftUI视图中使用,而在类中则不需要
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