在这种情况下，我设置了“主/细节”视图。从“事件”视图导航到“事件详细信息”视图。如果用户点击我使用“ Button（action：{self.presentationMode.wrappedValue.dismiss（）} ..”设计的“返回”按钮，则视图将暂时更改回“事件”列表，但随后跳转自动返回到用户正在浏览的详细信息视图。
这是“事件列表”页面上的代码
import SwiftUI
import Firebase
struct EventsView: View {
@Environment(\.presentationMode) var presentationMode: Binding<PresentationMode>
@State var data: [EventObject] = []
let db = Firestore.firestore()
var body: some View {
ZStack {
VStack {
List {
ForEach((self.data), id: \.self.eventID) { item in
NavigationLink(destination: EventDetail()) {
VStack {
HStack{
Text("\(item.eventDate)")
.font(.footnote)
.foregroundColor(Color("bodyText"))
Spacer()
}
HStack {
Text("\(item.eventTitle)")
.fontWeight(.bold)
.foregroundColor(Color("Charcoal"))
Spacer()
}.padding(.top, 8)
}.padding(.bottom, 16)
} // nav
}
Spacer()
}
.padding(.top, 60)
}
//Floating Navbar
ZStack {
VStack {
GeometryReader { gr in
HStack {
Button(action: {self.presentationMode.wrappedValue.dismiss()}) {
Image(systemName: "chevron.left")
.foregroundColor(Color("Charcoal"))
.padding(.leading, 16)
HStack {
Text("Explore · Disney Events")
.font(.system(size: 15))
.fontWeight(.bold)
.foregroundColor(Color("Charcoal"))
.padding()
Spacer()
}
}.frame(width: gr.size.width * 0.92, height: 48)
.background(Color("navBackground"))
.cornerRadius(8)
.shadow(color: Color("Shadow"), radius: 10, x: 2, y: 7)
}.padding(.leading, 16)
Spacer()
}
}
.padding(.top, 50)
.edgesIgnoringSafeArea(.top)
// Floating Nav Ends
}
}.onAppear(perform: self.queryEvents)
}
func queryEvents() {
self.data.removeAll()
self.db.collectionGroup("events").getDocuments() {(querySnapshot, err) in
if let err = err {
print("Error getting documents \(err)")
} else {
for document in querySnapshot!.documents {
let id = document.documentID
let title = document.get("eventTitle") as! String
let shortDesc = document.get("eventShort") as! String
let description = document.get("eventDescription") as! String
let date = document.get("eventDate") as! Timestamp
let aDate = date.dateValue()
let formatter = DateFormatter()
formatter.dateFormat = "E, MMM d · h:mm a"
let formattedTimeZoneStr = formatter.string(from: aDate)
let address = document.get("eventAddress") as! String
let cost = document.get("eventCost") as! Double
let location = document.get("eventLocation") as! String
let webURL = document.get("eventURL") as! String
self.data.append(EventObject(id: id, title: title, shortDesc: shortDesc, description: description, date: formattedTimeZoneStr, address: address, cost: cost, location: location, webURL: webURL))
}
}
}
}
}
class EventObject: ObservableObject {
@Published var eventID: String
@Published var eventTitle: String
@Published var eventShort: String
@Published var eventDescription: String
@Published var eventDate: String
@Published var eventAddress: String
@Published var eventCost: Double
@Published var eventLocation: String
@Published var eventURL: String
init(id: String, title: String, shortDesc: String, description: String, date: String, address: String, cost: Double, location: String, webURL: String) {
eventID = id
eventTitle = title
eventShort = shortDesc
eventDescription = description
eventDate = date
eventAddress = address
eventCost = cost
eventLocation = location
eventURL = webURL
}
}
事件详细信息在下面简化了代码。我试图带走东西寻找原因。它似乎与Firebase调用无关。
import SwiftUI
import Firebase
import MapKit
struct EventDetail: View {
@Environment(\.presentationMode) var presentationMode:
Binding<PresentationMode>
// var eventID: String
// var eventTitle: String
// var eventShort: String
// var eventDescription: String
// var eventDate: String
// var eventAddress: String
// var eventCost: Double
// var eventLocation: String
// var eventURL: String
var body: some View {
ZStack {
VStack {
GeometryReader { gr in
HStack {
Button(action: {self.presentationMode.wrappedValue.dismiss()}) {
Image(systemName: "chevron.left")
.foregroundColor(Color("Charcoal"))
.padding(.leading, 16)
HStack {
Text("Events · Event Details")
.font(.system(size: 15))
.fontWeight(.bold)
.foregroundColor(Color("Charcoal"))
.padding()
Spacer()
}
}.frame(width: gr.size.width * 0.92, height: 48)
.background(Color("navBackground"))
.cornerRadius(8)
.shadow(color: Color("Shadow"), radius: 10, x: 2, y: 7)
}.padding(.leading, 16)
Spacer()
}
}
.padding(.top, 50)
.edgesIgnoringSafeArea(.top)
}
}
}
这是一个视频，以说明我在说什么。Dropbox视频链接
这是一个基于您的视图的简化变体的可行方法的演示。这个想法是使用基于标记/选择的NavigationLink构造函数，并将绑定传递给选择，EventDetail以通过绑定停用选择，从而激活向后导航。
注意：我认为这presentationMode不是为导航方案设计的。
struct EventsView: View {
@State private var selectedItem: Int? = nil
var body: some View {
NavigationView {
List {
ForEach(0..<10, id: \.self) { item in
NavigationLink("Item \(item)", destination: EventDetail(selected: self.$selectedItem), tag: item, selection: self.$selectedItem)
}
}
}
}
}
struct EventDetail: View {
@Binding var selected: Int?
var body: some View {
VStack {
HStack {
Button(action: { self.selected = nil }) {
Image(systemName: "chevron.left")
HStack {
Text("Events · Event Details")
.padding()
Spacer()
}
}
.navigationBarHidden(true)
.navigationBarBackButtonHidden(true)
}
Spacer()
}
}
}
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