将视图作为视图修饰符内容传递给函数参数

Question

我正在创建一个可重复使用的自下而上面板，其中自下而上面板内显示的视图会有所不同。我还希望这个面板成为一个视图修改器。我过去创建过视图修饰符，但从未将视图作为视图修饰符内容传递。当我尝试通过视图时，出现如下所述的错误。

查看修改后的代码：

struct BottomPanel: ViewModifier {
    @Binding var isPresented: Bool
    let panelContent: Content

    init(isPresented: Binding<Bool>, @ViewBuilder panelContent: @escaping () -> Content) {
        self.panelContent = panelContent()
        self._isPresented = isPresented
    }

    func body(content: Content) -> some View {
        content.overlay(self.$isPresented.wrappedValue ? bottomPanelContent() : nil)
    }

    @ViewBuilder
    private func bottomPanelContent() -> some View {
        GeometryReader { geometry in
            VStack(spacing: 0) {
                self.panelContent
            }
            // some modifiers to change the color or height of the panel.
        }
    }
}

查看扩展：

extension View {
    func bottomPanel(isPresented: Binding<Bool>, @ViewBuilder panelContent: @escaping () -> BottomPanel.Content) -> some View {
        return modifier(BottomPanel(isPresented: isPresented, panelContent: panelContent)
    }
}

我希望在自下而上面板中打开的内容视图和子视图：

struct ContentView: View {
    @State var showBottomPanel: Bool = false

    var body: some View {
        VStack {
            Button(action: { self.showBottomPanel = true}) {
                Text("Click me to open bottom panel")
            }
        }
        .bottomPanel(isPresented: $self.showBottomPanel, panelContent: { ChildView() })
    }
}

struct ChildView: View {
    var body: some View {
        VStack {
            Button("Click Me 1", action: {}).foregroundColor(.blue)
            Button("Click Me 2", action: {}).foregroundColor(.red)
        }
    }
}

错误：Cannot convert value of type 'ChildView' to closure result type 'BottomPanel.Content' (aka '_ViewModifier_Content<BottomPanel>')。

我究竟做错了什么？如何将视图传递给 BottomPanel？

注意：我已经从底部面板中删除了很多代码以保持代码发布简短，但如果需要它，请告诉我，我可以分享。

谢谢阅读！

Answer 1

通过进行一些更改，我能够获得要呈现的内容。不知道如何内容是为了看起来，我不能明确地说这是否真的按照需要呈现了内容 -但它仍然显示内容，规避了您试图绕过的错误

import Foundation
import SwiftUI

struct ContentView: View {
    @State var showBottomPanel: Bool = false
    
    var body: some View {
        VStack {
            Button(action: { self.showBottomPanel = true}) {
                Text("Click me to open bottom panel")
            }
        }
        .bottomPanel(isPresented: $showBottomPanel, panelContent: { ChildView() }())
    }
}

struct ChildView: View {
    var body: some View {
        VStack {
            Button("Click Me 1", action: {}).foregroundColor(.blue)
            Button("Click Me 2", action: {}).foregroundColor(.red)
        }
    }
}



extension View {
    func bottomPanel(isPresented: Binding<Bool>, panelContent: ChildView) -> some View {
        return modifier(BottomPanel(isPresented: isPresented, panelContent: ChildView()))
    }
}


struct BottomPanel: ViewModifier {
    @Binding var isPresented: Bool
    let panelContent: ChildView
    
    init(isPresented: Binding<Bool>, panelContent: ChildView) {
        self.panelContent = ChildView()
        self._isPresented = isPresented
    }
    
    func body(content: Content) -> some View {
        content.overlay(self.$isPresented.wrappedValue ? bottomPanelContent() : nil)
    }
    
    @ViewBuilder
    private func bottomPanelContent() -> some View {
        GeometryReader { geometry in
            VStack(spacing: 0) {
                self.panelContent
            }
            // some modifiers to change the color or height of the panel.
        }
    }
}