SwiftUI中App协议不兼容及Binding视图传参错误求助

1. App协议兼容错误 #

为Market_ExampleApp添加带Binding参数的初始化方法后，触发错误：Type 'Market_ExampleApp' does not conform to protocol 'App'

2. MarketplaceShirtView类型转换错误 #

调用ShirtDetailView时出现两个类型不匹配问题：

• 无法将$showDetailShirt（Binding<Bool>类型）转换为预期的Bool类型
• 无法将Binding<Shirt>类型转换为预期的Shirt类型

Market_ExampleApp代码 #

@main
struct Market_ExampleApp: App {

    @StateObject var appModel: AppViewModel = .init()
    @StateObject var sharedData: SharedDataModel = SharedDataModel()
    @Binding var shirtData : Shirt
    @Binding var showDetailShirt: Bool
    @Binding var trouserData : Trouser
    @Binding var showDetailTrouser: Bool

    init(shirtData: Binding<Shirt>, showDetailShirt: Binding<Bool>, trouserData: Binding<Trouser>, showDetailTrouser: Binding<Bool>){ 
        self._shirtData = shirtData
        self._showDetailShirt = showDetailShirt
        self._trouserData = trouserData
        self._showDetailTrouser = showDetailTrouser

        UITabBar.appearance().isHidden = true
    }
    
    @UIApplicationDelegateAdaptor(Appdelegate.self) var delegate
    var body: some Scene {
        WindowGroup {
            ContentView(shirtData: $shirtData, showDetailShirt: $showDetailShirt, trouserData: $trouserData, showDetailTrouser: $showDetailTrouser)
                .onOpenURL(perform: { url in
                    Auth.auth().canHandle(url)
                })
        }
    }
}

ContentView代码 #

import SwiftUI

struct ContentView: View {
  
    @AppStorage("log_status") var log_Status: Bool = false
    @StateObject var appModel: AppViewModel = .init()
    
    @StateObject var sharedData: SharedDataModel = SharedDataModel()
    
    @Binding var shirtData : Shirt
    @Binding var showDetailShirt: Bool

    @Binding var trouserData : Trouser
    @Binding var showDetailTrouser: Bool
    
    init(shirtData: Binding<Shirt>, showDetailShirt: Binding<Bool>, trouserData: Binding<Trouser>, showDetailTrouser: Binding<Bool>){ 
        self._shirtData = shirtData
        self._showDetailShirt = showDetailShirt
        self._trouserData = trouserData
        self._showDetailTrouser = showDetailTrouser
        
        UITabBar.appearance().isHidden = true
    }
    
    var body: some View {
        Group{
            if log_Status{
                MainPage(shirtData: $shirtData, showDetailShirt: $showDetailShirt, trouserData: $trouserData, showDetailTrouser: $showDetailTrouser)
            }
            else{
                OnBoardingPage()
            }
        }
    }
}

MarketplaceShirtView代码 #

import SwiftUI

struct MarketplaceShirtView: View {
    
    @EnvironmentObject var appModel: AppViewModel
    @StateObject var MarketplaceModel = MarketplaceViewModel()
    @State private var selectedMarketplaceFilter: MarketplaceFilterViewModel = .shirt
    @Namespace var animation : Namespace.ID 
    @State var showDetailShirt = false
    @State var selectedShirt : Shirt!
    
    @EnvironmentObject var sharedData: SharedDataModel
    
    var body: some View {
        
        var columns = Array(repeating: GridItem(.flexible()), count: 2)
        
        ZStack{
            
            VStack(spacing: 10){
                                     
                HStack {
                    
                    Text("Find Shirts To Buy")
                        
                    }
                
                 }
            }
                
                if MarketplaceModel.shirts.isEmpty{
                    
                    ProgressView()
                   
                }
                else{
                    
                    ScrollView {
                        

                        LazyVGrid(columns: Array(repeating: GridItem(){
                            
                            ForEach(MarketplaceModel.filteredShirt){shirt in
                                                                                
                                    ShirtView(shirtData: shirt)

                                        .onTapGesture {
                                            
                                                selectedShirt = shirt
                                                showDetailShirt.toggle()
     
                                        }
                            }
                        }
                    })
                }
            }
            
            if selectedShirt != nil && showDetailShirt{
                
                ShirtDetailView(shirtData: Binding($selectedShirt)!, showDetailShirt: $showDetailShirt,animation: _animation)
            }
}
}

修复App协议兼容问题 #

SwiftUI的App协议要求入口结构体必须提供无参数初始化方法，自定义带参数初始化会违反协议规则。正确做法是将共享状态放在顶层用@State声明，而非通过Binding传递给App结构体：

修改后的Market_ExampleApp代码：

@main
struct Market_ExampleApp: App {
    @StateObject var appModel: AppViewModel = .init()
    @StateObject var sharedData: SharedDataModel = SharedDataModel()
    // 将状态改为顶层@State，而非Binding
    @State var shirtData: Shirt = Shirt()
    @State var showDetailShirt: Bool = false
    @State var trouserData: Trouser = Trouser()
    @State var showDetailTrouser: Bool = false

    // 恢复无参数初始化
    init(){
        UITabBar.appearance().isHidden = true
    }
    
    @UIApplicationDelegateAdaptor(Appdelegate.self) var delegate
    var body: some Scene {
        WindowGroup {
            ContentView(shirtData: $shirtData, showDetailShirt: $showDetailShirt, trouserData: $trouserData, showDetailTrouser: $showDetailTrouser)
                .onOpenURL(perform: { url in
                    Auth.auth().canHandle(url)
                })
                // 将全局对象注入环境，避免重复初始化
                .environmentObject(appModel)
                .environmentObject(sharedData)
        }
    }
}

同时修改ContentView，用@EnvironmentObject接收全局对象：

struct ContentView: View {
    @AppStorage("log_status") var log_Status: Bool = false
    // 通过环境接收全局对象，而非重新初始化
    @EnvironmentObject var appModel: AppViewModel
    @EnvironmentObject var sharedData: SharedDataModel
    
    @Binding var shirtData : Shirt
    @Binding var showDetailShirt: Bool
    @Binding var trouserData : Trouser
    @Binding var showDetailTrouser: Bool
    
    init(shirtData: Binding<Shirt>, showDetailShirt: Binding<Bool>, trouserData: Binding<Trouser>, showDetailTrouser: Binding<Bool>){ 
        self._shirtData = shirtData
        self._showDetailShirt = showDetailShirt
        self._trouserData = trouserData
        self._showDetailTrouser = showDetailTrouser
        UITabBar.appearance().isHidden = true
    }
    
    var body: some View {
        Group{
            if log_Status{
                MainPage(shirtData: $shirtData, showDetailShirt: $showDetailShirt, trouserData: $trouserData, showDetailTrouser: $showDetailTrouser)
            }
            else{
                OnBoardingPage()
            }
        }
    }
}

修复MarketplaceShirtView类型转换错误 #

问题源于ShirtDetailView的参数定义与传递类型不匹配，分两种情况处理：

情况1：ShirtDetailView需要值类型参数 #

如果ShirtDetailView的参数是Shirt和Bool，直接传递值即可：

// 替换原错误调用代码
if let selectedShirt = selectedShirt, showDetailShirt {
    ShirtDetailView(shirtData: selectedShirt, showDetailShirt: showDetailShirt, animation: animation)
}

情况2：ShirtDetailView需要Binding类型参数 #

如果ShirtDetailView的参数是Binding<Shirt>和Binding<Bool>，直接用$符号传递绑定，同时修正animation的传递方式：

// 先确保ShirtDetailView的定义是Binding参数
struct ShirtDetailView: View {
    @Binding var shirtData: Shirt
    @Binding var showDetailShirt: Bool
    var animation: Namespace.ID
    
    var body: some View {
        // 视图内容
    }
}

// 调用时的正确写法
if let selectedShirt = selectedShirt, showDetailShirt {
    ShirtDetailView(shirtData: $selectedShirt, showDetailShirt: $showDetailShirt, animation: animation)
}

同时修正MarketplaceShirtView的语法错误（括号不匹配、强制解包风险）：

struct MarketplaceShirtView: View {
    @EnvironmentObject var appModel: AppViewModel
    @StateObject var marketplaceModel = MarketplaceViewModel()
    @State private var selectedMarketplaceFilter: MarketplaceFilterViewModel = .shirt
    @Namespace var animation
    @State var showDetailShirt = false
    @State var selectedShirt: Shirt? // 改为可选类型，避免强制解包
    
    @EnvironmentObject var sharedData: SharedDataModel
    
    var body: some View {
        let columns = Array(repeating: GridItem(.flexible()), count: 2)
        
        ZStack{
            VStack(spacing: 10){
                HStack {
                    Text("Find Shirts To Buy")
                }
            }
            
            if marketplaceModel.shirts.isEmpty {
                ProgressView()
            } else {
                ScrollView {
                    LazyVGrid(columns: columns) {
                        ForEach(marketplaceModel.filteredShirt) { shirt in
                            ShirtView(shirtData: shirt)
                                .onTapGesture {
                                    selectedShirt = shirt
                                    showDetailShirt.toggle()
                                }
                        }
                    }
                }
            }
            
            if let selectedShirt = selectedShirt, showDetailShirt {
                ShirtDetailView(shirtData: $selectedShirt, showDetailShirt: $showDetailShirt, animation: animation)
            }
        }
    }
}

内容的提问来源于stack exchange，提问作者Mxyb