SwiftUI 测量视图的高度 [英] SwiftUI measuring the height of a view

问题描述

我尝试使用 coordinatespace 测量视图的高度，但它返回的值是全屏的高度.知道为什么我的代码没有给我我想要的吗?

I tried measuring the height of a view by using coordinatespace on it but the value it returns is the height of the full screen. Any idea why my code isn't giving me what I want ?

struct GeoReader: View {
    var body: some View {
        GeometryReader { geo in
            VStack {
                ZStack {
                    Rectangle()
                        .foregroundColor(.blue)
                    Text("Heigt of full screen is \(geo.size.height)")
                }
                ZStack {
                    Rectangle()
                        .foregroundColor(.red)
                        .coordinateSpace(name: "Redbox")
                    Text("Height of red box is \(geo.frame(in: .named("Redbox")).height)")
                }
            }
        }
    }
}

推荐答案

显示大小是作为内部视图的容器的完整视图的尺寸.

The showing size is the dimension of the full view that is the container of the inner view.

您需要使用另一个 GeometryReader 来获取第二个 ZStack 的内部维度.

You need to use another GeometryReader to get the inner dimension of a second ZStack.

struct ContentView: View {
    var body: some View {
        GeometryReader { geo in
            VStack {
                ZStack {
                    Rectangle()
                        .foregroundColor(.blue)
                    Text("Heigt of full screen is \(geo.size.height)")
                }
                GeometryReader { innterGeo in //<Here
                    ZStack {
                        Rectangle()
                            .foregroundColor(.red)
                            .coordinateSpace(name: "Redbox")
                        Text("Height of red box is \(innterGeo.frame(in: .named("Redbox")).height)")
                    }
                }
            }
        }
    }
}

---

如果你需要在任何地方使用它，那么你可以使用这个方法.

---

if you need to use this in any places then you can use this approch.

首先，创建一个结构体并使用 GeometryReader 包装您的内容.

First, create one struct and wrapped your content with GeometryReader.

struct GeometryContentSize<Content: View>: View {
    public var content: (CGSize) -> Content
    
    var body: some View {
        GeometryReader { geo in
            content(geo.size)
        }
    }
}

用法:

struct ContentView: View {
    var body: some View {
        GeometryReader { geo in
            VStack {
                ZStack {
                    Rectangle()
                        .foregroundColor(.blue)
                    Text("Heigt of full screen is \(geo.size.height)")
                }
                
                GeometryContentSize { (size) in //<--- Here
                    ZStack {
                        Rectangle()
                            .foregroundColor(.red)
                        Text("Height of red box is \(size.height)")
                    }
                }
            }
        }
    }
}

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