iOS16后SwiftUI程序化选中列表项及解决数组传参错误

在iOS 16及以后，Apple弃用了NavigationLink(tag:selection:) API，取而代之的是NavigationStack结合NavigationPath的方式实现程序化导航。以下是修改后的代码，启动时会直接跳转到"Math"对应的详情页：

import SwiftUI
import Foundation

// 让BookItem遵循Hashable，才能加入NavigationPath
struct BookItem: Hashable {
    let id: Int
    let name: String
    
    init(id: Int, name: String) {
        self.id = id
        self.name = name
    }
}

struct ContentView: View {
    let bookList: [BookItem] = [BookItem(id: 0, name: "History"), 
                                BookItem(id: 1, name: "Math"), 
                                BookItem(id: 2, name: "Science")]

    let selectBookItemId: Int = 1
    // 管理导航路径的状态变量
    @State private var path = NavigationPath()
    
    var body: some View {
        // 绑定path到NavigationStack
        NavigationStack(path: $path) {
            List(bookList, id: \.id) { bookItem in
                // 用按钮触发导航，也可替换为NavigationLink(value: bookItem) { ... }
                Button {
                    path.append(bookItem)
                } label: {
                    HStack {
                        Text(bookItem.name)
                        Spacer()
                    }
                    .contentShape(Rectangle())
                }
            }
            // 指定BookItem类型对应的导航目标视图
            .navigationDestination(for: BookItem.self) { bookItem in
                DetailsView(bookItem: bookItem)
            }
            // 页面加载时自动跳转到指定条目
            .onAppear {
                if let targetBook = bookList.first(where: { $0.id == selectBookItemId }) {
                    path.append(targetBook)
                }
            }
        }
    }
}

struct DetailsView: View {
    var bookItem: BookItem

    var body: some View {
        VStack {
            Text(bookItem.name)
                .font(.body.bold())
                .foregroundColor(.blue)
        }
    }
}

你遇到的Cannot convert value of type 'String' to expected argument type '[String]'错误，核心是导航目标声明的类型和实际传递的类型不匹配：你往path里添加的是[String]类型的listing，但navigationDestination声明要处理String类型，导致类型冲突。

下面是两种修正方案，推荐第一种（更符合数据逻辑）：

方案一：传递完整的BookItem（推荐） #

直接把整个BookItem传给详情页，便于后续扩展，不需要单独传递数组：

import SwiftUI
import Foundation

struct BookItem: Hashable {
    let id: Int
    let name: String
    let listing: [String]
    
    init(id: Int, name: String, listing: [String]) {
        self.id = id
        self.name = name
        self.listing = listing
    }
}

struct ContentView: View {
    let bookList: [BookItem] = [BookItem(id: 0, name: "History", listing: ["1", "2"]),
                                BookItem(id: 1, name: "Math", listing: ["1", "2"]),
                                BookItem(id: 2, name: "Science", listing: ["1", "2"])]

    let selectBookItemId: Int
    @State private var path = NavigationPath()
    
    var body: some View {
        NavigationStack(path: $path) {
            List(bookList, id: \.id) { bookItem in
                Button {
                    path.append(bookItem)
                } label: {
                    HStack {
                        Text(bookItem.name)
                        Spacer()
                    }
                    .contentShape(Rectangle())
                }
            }
            // 指定处理BookItem类型的导航
            .navigationDestination(for: BookItem.self) { bookItem in
                DetailsView(listing: bookItem.listing)
            }
            .onAppear {
                if let targetBook = bookList.first(where: { $0.id == selectBookItemId }) {
                    path.append(targetBook)
                }
            }
        }
    }
}

struct DetailsView: View {
    var listing: [String]

    var body: some View {
        VStack {
            // 遍历显示数组内容
            ForEach(listing, id: \.self) { item in
                Text(item)
            }
        }
    }
}

方案二：直接传递[String]类型 #

如果确实只需要传递数组，要确保navigationDestination的类型和传递的类型完全一致：

import SwiftUI
import Foundation

struct BookItem: Hashable {
    let id: Int
    let name: String
    let listing: [String]
    
    init(id: Int, name: String, listing: [String]) {
        self.id = id
        self.name = name
        self.listing = listing
    }
}

struct ContentView: View {
    let bookList: [BookItem] = [BookItem(id: 0, name: "History", listing: ["1", "2"]),
                                BookItem(id: 1, name: "Math", listing: ["1", "2"]),
                                BookItem(id: 2, name: "Science", listing: ["1", "2"])]

    let selectBookItemId: Int
    @State private var path = NavigationPath()
    
    var body: some View {
        NavigationStack(path: $path) {
            List(bookList, id: \.id) { bookItem in
                Button {
                    path.append(bookItem.listing)
                } label: {
                    HStack {
                        Text(bookItem.name)
                        Spacer()
                    }
                    .contentShape(Rectangle())
                }
            }
            // 修改为[String].self，匹配传递的数组类型
            .navigationDestination(for: [String].self) { listing in
                DetailsView(bookItem: listing)
            }
            .onAppear {
                if let targetBook = bookList.first(where: { $0.id == selectBookItemId }) {
                    path.append(targetBook.listing)
                }
            }
        }
    }
}

struct DetailsView: View {
    var bookItem: [String]

    var body: some View {
        VStack {
            ForEach(bookItem, id: \.self) { item in
                Text(item)
            }
        }
    }
}

内容的提问来源于stack exchange，提问作者tech_human