SwiftUI 列表行 onTapGesture 来处理推送

Question

• 我有一个带有非可选person变量的 DetailView：

struct DetailView: View {
    let person: Person
    var body: some View {
        VStack {
            Text("Person Name: \(person.name)")
            Text("Person Email: \(person.email)")
        }
    }
}

class Person: Identifiable {
    let id = UUID()
    let name: String
    let email: String
    init(name: String, email: String) {
        self.name = name
        self.email = email
    }
}

• 我有一个 ContentView（主屏幕），加载人员 ID 列表：

struct ContentView: View {
    private let personIDs: [String] = ["xx1", "xx2", "xx3", "xx4", "xx5"]
    var body: some View {
        NavigationView(content: {
            List(self.personIDs, id: \.self) { personID in
                Text("personID: \(personID)")
            }
        })
    }
}

• 这里的问题是当我点击行时，我想在推送到 DetailView 之前从服务器获取人员数据，但是遇到了问题：

struct ContentView: View {
    private let personIDs: [String] = ["xx1", "xx2", "xx3", "xx4", "xx5"]
    var body: some View {
        NavigationView(content: {
            List(self.personIDs, id: \.self) { personID in
                Text("personID: \(personID)")
                    .onTapGesture {
                        // Load Person data (by `personID`) from server.
                        // How can I push to DetailView here?
                    }
            }
        })
    }
}

• 我曾尝试使用 NavigationLink，但没有用于 DetailView 初始化的person数据：

struct ContentView: View {
    private let personIDs: [String] = ["xx1", "xx2", "xx3", "xx4", "xx5"]
    var body: some View {
        NavigationView(content: {
            List(self.personIDs, id: \.self) { personID in
                // `person` argument is non-optional
                // no `person: Person` data here
                NavigationLink(destination: DetailView(person: /* ??? */)) {
                    Text("personID: \(personID)")
                        .onTapGesture {
                            // Load Person data (by `personID`) from server.
                            // ???
                        }
                }
            }
        })
    }
}

• 有没有人遇到过这个问题以及如何解决？

Answer 1

最后，我找到了修复它的方法。 感谢@William Hu 在这篇文章中SwiftUI NavigationLink：如何在显示目标视图之前调用函数

具体来说，对于我的问题：

struct ContentView: View {
    
    private let personIDs: [String] = ["xx1", "xx2", "xx3", "xx4", "xx5"]
    @State private var person: Person = Person(name: "", email: "")
    @State private var navigationLinkTriggerer: String? = nil
    
    var body: some View {
        NavigationView(content: {
            List(self.personIDs, id: \.self) { personID in
                Button(action: {
                    // --- --- ---
                    // Simulate loading data from server
                    self.person = Person(name: "\(personID) Name", email: "\(personID)@gmail.com")
                    
                          // ---
                          // Completion Handler
                          self.navigationLinkTriggerer = personID
                          // ---
                    
                    // --- --- ---
                }, label: {
                    NavigationLink(destination: DetailView(person: person),
                                   tag: personID,
                                   selection: self.$navigationLinkTriggerer) {
                        Text("personID: \(personID)")
                    }
                })
                
            }
        })
    }
}