我有一个 SwiftUI 应用程序,其中有几个 View 是使用 MapKit 制作的 map UIViewRepresentable。我有兴趣点和使用的自定义注释 用于进一步操作的左右标注按钮。在右边我只是想要 显示有关航路点的信息。在左侧,我想发出警报 进一步操作的选择 - 例如,插入一个新的注释点。前 SwiftUI 我刚刚发出警报并执行了上述两项操作。但据我所知, UIViewRepresentable 版本上没有 self.present。因此我没有去过 能够显示警报。
只是为了实验 - 我将 SwiftUI 警报代码附加到 SwiftUI View 调用 map View 。使用 Observable bool 值我确实可以引发这两个警报。 这对我来说似乎很奇怪,但也许是绑定(bind)到全局属性的警报代码 可以在任何地方。
我的第一次尝试:(结构是 DetailMapView)
func mapView(_ mapView: MKMapView, annotationView view: MKAnnotationView, calloutAccessoryControlTapped control: UIControl) {
if control == view.leftCalloutAccessoryView {
guard let tappedLocationCoord = view.annotation?.coordinate else {return}
let tappedLocation = CLLocation(latitude: tappedLocationCoord.latitude, longitude: tappedLocationCoord.longitude)
let ac = UIAlertController(title: nil, message: nil, preferredStyle: .alert)
let deleteAction = UIAlertAction(title: "Delete Waypoint", style: .destructive) { (action) in
//some stuff
}
let insertAction = UIAlertAction(title: "Insert Waypoint After This", style: .default) { (action) in
//some stuff
}
let cancelAction = UIAlertAction(title: "Cancel", style: .default) { (action) in
//some stuff
}//cancelAction
ac.addAction(deleteAction)
ac.addAction(insertAction)
ac.addAction(cancelAction)
//tried adding self, referencing parent - always error saying
//the object does not have a .present
mapView.present(ac, animated: true)
} else if control == view.rightCalloutAccessoryView {
//more of the same
}
}//annotationView
然后我删除了警报代码并添加了:
parent.userDefaultsManager.shouldShowAnnotationEditMenu.toggle()
我将通话屏幕更改为:
@ObservedObject var userDefaultsManager: UserDefaultsManager
var aTrip: Trip?
var body: some View {
VStack {
Text(aTrip?.name ?? "Unknown Map Name")
.padding(.top, -50)
.padding(.bottom, -20)
DetailMapView(aTrip: aTrip, userDefaultsManager: userDefaultsManager)
.padding(.top, -20)
.alert(isPresented: $userDefaultsManager.shouldShowAddress) {
//Alert(title: Text("\(aTrip?.name ?? "No") Address"),
Alert(title: Text(self.userDefaultsManager.approximateAddress),
message: Text("This is the approximate street address."),
dismissButton: .default(Text("Got it!")))
}//.alert shouldShowAddress
Text("This is the view where the trip information will be displayed.")
.multilineTextAlignment(.center)
.alert(isPresented: $userDefaultsManager.shouldShowAnnotationEditMenu) {
Alert(title: Text("Edit Annotations"),
message: Text("Choose this to insert an Annotation."),
dismissButton: .default(Text("Got it!")))
}//.alert shouldShowAddress
}
}
我想如果这安全的话我可以让它工作——但它看起来比它更复杂 应该是。
思路是这样的:
任何指导将不胜感激:Xcode 版本 11.3.1 (11C504)
最佳答案
我为此花了一个小时,我是 SwiftUI 的新手,我跳进去只是为了回答一些简单的问题。
一种方法是使用 Bool
(@State
和 @Binding
)。
您还需要有一个View
,而不是直接在您的SceneDelegate
中使用您的UIViewRepresentable
。因为那是您链接警报
的地方。
像这样:
struct MainView: View {
@State var text = ""
@State var showingAlert: Bool
var body: some View {
VStack {
MapView(showingAlert: self.$showingAlert)
.alert(isPresented: $showingAlert) { () -> Alert in
print("SHOWING ALERT BODY: --> \($showingAlert.wrappedValue)")
return Alert(title: Text("Important message"), message: Text("Go out and have a girlfriend!"), dismissButton: .default(Text("Got it!")))
}
}
}
}
然后你的 MapView
应该是这样的:
struct MapView: UIViewRepresentable {
let landmarks = LandmarkAnnotation.requestMockData()
@Binding var showingAlert: Bool
func makeCoordinator() -> MapViewCoordinator {
MapViewCoordinator(mapView: self, showingAlert: self.$showingAlert)
}
/**
- Description - Replace the body with a make UIView(context:) method that creates and return an empty MKMapView
*/
func makeUIView(context: Context) -> MKMapView {
MKMapView(frame: .zero)
}
func updateUIView(_ view: MKMapView, context: Context){
//If you changing the Map Annotation then you have to remove old Annotations
//mapView.removeAnnotations(mapView.annotations)
view.delegate = context.coordinator
view.addAnnotations(landmarks)
}
}
struct MapView_Previews: PreviewProvider {
static var previews: some View {
MapView(showingAlert: Binding<Bool>.constant(true))
}
}
最后,在您的 MapViewCoordinator
中(我想您有这个类,这是实现 MKMapViewDelegate
的委托(delegate)方法的类。)。
/*
Coordinator for using UIKit inside SwiftUI.
*/
class MapViewCoordinator: NSObject, MKMapViewDelegate {
var mapViewController: MapView!
@Binding var showAlert: Bool
init(mapView: MapView, showingAlert: Binding<Bool>) {
self.mapViewController = mapView
self._showAlert = showingAlert
super.init()
}
func mapView(_ mapView: MKMapView, viewFor
annotation: MKAnnotation) -> MKAnnotationView?{
//Custom View for Annotation
let annotationView = MKAnnotationView(annotation: annotation, reuseIdentifier: "customView")
annotationView.canShowCallout = true
//Your custom image icon
annotationView.image = UIImage(named: "locationPin")
return annotationView
}
func mapView(_ mapView: MKMapView, annotationView view: MKAnnotationView, calloutAccessoryControlTapped control: UIControl) {
print("calloutAccessoryControlTapped")
}
func mapView(_ mapView: MKMapView, didSelect view: MKAnnotationView) {
print("didSelect")
self.showAlert = true
}
}
如您所见,我只使用了 Bool 标志。特别是 @Binding
一个。
关于ios - SwiftUI MapKit UIViewRepresentable 无法显示警报,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/60348668/