从另一个视图返回文本错误，缺少参数参数

Posted 2023-02-24

【中文标题】从另一个视图返回文本错误，缺少参数参数

【英文标题】：Return Text from another view Error, missing argument parameter

【发布时间】：2021-10-19 10:25:00

【问题描述】：

struct SettingsView: View 
    
    var body: some View 
         
         welcomeView()    
              //:Missing argument for parameter 'currentAuthStat' in call

     


struct welcomeView: View 
    @Binding var currentAuthStat: UNNotificationSetting
    
    var body: some View 
        explanatoryText
    
    
    
    private var explanatoryText: Text 
        let explanatoryText: Text
        switch currentAuthStat 
        case .enabled:
            explanatoryText = Text("Notifications are enabled")
            + Text(Image(systemName: "checkmark"))
        default:
            explanatoryText = Text("Notifications disabled ")
            + Text(Image(systemName: "x.squareroot")) 
        
        return explanatoryText
    //: explanatoryText

当我尝试在 SettingsView 中显示 welcomeView() 时出现错误 “调用中缺少参数‘currentAuthStat’的参数” 我尝试将@State var 添加到 SettingsView 但是它给了我一个错误来在 ContentView 中进行调用，当我将它添加到 ContentView 时它希望我将它添加到 App @main 页面然后我得到一个错误应用程序确实不符合 View()。

如何将此解释性文本传递给另一个视图？

【参考方案1】：

你应该好好学习和学习@State 和@Binding 的使用，因为它是 使用 SwiftUI。这是解决您收到的错误的一种可能方法：

import SwiftUI

@main
struct TesttApp: App 
    var body: some Scene 
        WindowGroup 
            ContentView()
        
    

struct ContentView: View 
    var body: some View 
        SettingsView()
    

 
struct SettingsView: View 
    @State var currentAuthStat: UNNotificationSetting = .enabled // <-- here give it a value
    
    var body: some View 
        welcomeView(currentAuthStat: currentAuthStat) // <-- pass it to the welcomeView
    


struct welcomeView: View 
    // unless you change currentAuthStat, there is no need for Binding
    @State var currentAuthStat: UNNotificationSetting // <-- here receive the value
    
    var body: some View 
        explanatoryText
    
    
    private var explanatoryText: Text 
        let explanatoryText: Text
        switch currentAuthStat 
        case .enabled:
            explanatoryText = Text("Notifications are enabled")
            + Text(Image(systemName: "checkmark"))
        default:
            explanatoryText = Text("Notifications disabled ")
            + Text(Image(systemName: "x.squareroot"))
        
        return explanatoryText
    //: explanatoryText

EDIT1：currentAuthStat 被用户更改的情况：

struct welcomeView: View 
    // if you want to change currentAuthStat, use a Binding
    @Binding var currentAuthStat: UNNotificationSetting // <--- here a Binding 
    
    var body: some View 
        VStack (spacing: 55)
            explanatoryText
            Button("disabled setting")
                currentAuthStat = .disabled  // <--- here test change
            
        
    
    
    private var explanatoryText: Text 
        let explanatoryText: Text
        switch currentAuthStat 
        case .enabled:
            explanatoryText = Text("Notifications are enabled")
            + Text(Image(systemName: "checkmark"))
        default:
            explanatoryText = Text("Notifications disabled ")
            + Text(Image(systemName: "x.squareroot"))
        
        return explanatoryText
    //: explanatoryText
 

    

【讨论】：

如果我将此设置设置为 .enabled，然后将覆盖该设置为 .enabled，我希望返回当前设置，这取决于用户是否允许通知。

正如我在代码中提到的，“除非你更改currentAuthStat，否则不需要Binding”。这意味着，如果您希望用户更改currentAuthStat，请使用Binding。我已经用这样一个例子更新了我的答案。

感谢您的帮助，谢谢。