如何更改返回視圖類型<tupleview<(view, view)> > 到 <_> 進行初始化？ </tupleview<(view,>

Question

我有一個以<TupleView<(View, View)>>形式返回視圖的視圖，如下所示：

我還有一個以<_>形式返回視圖的視圖，如下所示：

知道這兩種方法都有效並且我希望的方法是在掩護下使用TupleView但具有<_>的外觀，我嘗試在MyView3上工作，正如您在我嘗試過的代碼中看到的那樣我想要這種外觀(content: () -> _) -> MyView3<_>更簡單易懂，但我需要 TupleView 方式初始化卧底。 我為MyView3遇到了 3 個錯誤以使其正常工作。 你認為有沒有辦法實現我的目標？

有關詳細信息，請參閱此代碼：

struct ContentView: View {
    var body: some View {
        
        MyView1(content: {
            Text("Text 1").fixedSize()
            Text("Text 2").fixedSize()
        })
            .padding()

        MyView2(tupleViewContent: {
            Text("Text 3").fixedSize()
            Text("Text 4").fixedSize()
        })
            .padding()

        // This part has issue!
        MyView3(content: {
            Text("Text 5").fixedSize()
            Text("Text 6").fixedSize()
        })
            .padding()

    }
}

struct MyView1<Content: View>: View {
    
    let content: () -> Content
    
    init(@ViewBuilder content: @escaping () -> Content) {
        self.content = content
    }
    
    var body: some View {
        content()
    }
}

struct MyView2<Content: View>: View {
    
    let content: () -> Content
    
    init<Content1: View, Content2: View>(@ViewBuilder tupleViewContent: @escaping () -> Content) where Content == TupleView<(Content1, Content2)> {
        self.content = tupleViewContent
    }
    
    var body: some View {
        content()
    }
}

struct MyView3<Content: View>: View {

    let content: () -> Content

    private init<Content1: View, Content2: View>(@ViewBuilder tupleViewContent: @escaping () -> Content) where Content == TupleView<(Content1, Content2)> {
         self.content = tupleViewContent
    }
    
    init(@ViewBuilder content: @escaping () -> Content) {
        
        //Error:
        // Generic parameter 'Content1' could not be inferred
        // Generic parameter 'Content2' could not be inferred
        // Initializer 'init(tupleViewContent:)' requires the types 'Content' and 'TupleView<(Content1, Content2)>' be equivalent
        self.init(tupleViewContent: content)
        
    }
    
    var body: some View {
        content()
    }
}

Answer 1

generics是在編譯時解析的，所以init/s應該go從more specific到more common（最后到designated one）。

在你的情況下它應該像（用 Xcode 13.2 測試）

struct MyView3<Content: View>: View {

    let content: () -> Content

    init<Content1: View, Content2: View>(@ViewBuilder tupleViewContent: @escaping () -> Content) where Content == TupleView<(Content1, Content2)> {
         self.init(content: tupleViewContent)
    }

    init(@ViewBuilder content: @escaping () -> Content) {
        self.content = content
    }

    var body: some View {
        content()
    }
}