SwiftUI - How to get GeometryReader size/height from different View?

Question

How can I access the size of a View from another View?

To get the height of the "Hello world!" text, I attached a .background() of GeometryReader to it. For now, I'm just printing the height using let _ = print(proxy.size.height).

struct ContentView: View {
    var body: some View {
        VStack {
            Text("Hello world!")
                .background(
                    GeometryReader { proxy in
                        Color.clear /// placeholder
                        let _ = print(proxy.size.height) /// 20.333333333333332
                    }
                )
            
            Text("Height of first text is ???")
        }
    }
}

Result:

I now want to replace ??? with the height of the "Hello world!". How can I do this?

Similar question: https://stackoverflow.com/a/59733037/14351818 — aheze, Dec 04 '21 at 20:42

score 4 · Accepted Answer · answered Apr 25 '21 at 19:34

You can:

Make a @State property to store the height
Set it using an .onAppear { attached to Color.clear
Replace ??? with \(textHeight)

struct ContentView: View {
    @State var textHeight = CGFloat(0) /// 1.

    var body: some View {
        VStack {
            Text("Hello world!")
                .background(
                    GeometryReader { proxy in
                        Color.clear
                            .onAppear { /// 2.
                                textHeight = proxy.size.height
                            }
                    }
                )
                                          /// 3.
            Text("Height of first text is \(textHeight)") 
        }
    }
}

Result:

`onAppear` is only called when it appears, so it doesn't handle orientation changes. — aheze, May 25 '21 at 22:15
I spoke to an Apple engineer during WWDC21 and they said that to handle orientation, attach a `.onChange`. — aheze, Jun 22 '21 at 21:54

SwiftUI - How to get GeometryReader size/height from different View?

1 Answers1