How to access parents frame in SwiftUI

Question

Still working on SwiftUI, but I got a problem. I created an Image with a dynamic frame, and I want a label which needs to be half width of the image (e.g Image width = 300; Label width 150)

In UIKit I should code something like this:

Label.widthAnchor.constraint(image.widthAnchor, multiplier: 1/2).isActive = true

I tried something similar in SwiftUI:

Image(systemName: "j.circle.fill")
            .resizable()
            .frame(width: UIScreen.main.bounds.width, height: UIScreen.main.bounds.width)
        Text("Placeholder").frame(width: Image.frame.width/2, height: 30)

But this doesn't work.

What shall I do?

Geometry Reader is a possible solution. Take a look into this thread. https://stackoverflow.com/questions/56729619/what-is-geometry-reader-in-swiftui — Md Shafiul Islam, Jul 01 '19 at 11:48

Bogdan Farca · Accepted Answer · 2019-07-01T09:31:57.293

2

Why not setting hard sizes for both then :

Image(systemName: "j.circle.fill")
     .resizable()
     .frame(width: UIScreen.main.bounds.width, height: UIScreen.main.bounds.width)

Text("Placeholder")
     .frame(width: UIScreen.main.bounds.width/2, height: 30)

If you want to change the whole size of the component in one place you could just do it like this :

struct MyView : View {

     private var compWidth: CGFloat { UIScreen.main.bounds.width }

     var body: some View {
         VStack {
             Image(systemName: "j.circle.fill")
                   .resizable()
                   .frame(width: compWidth, height: compWidth)

             Text("Placeholder")
                   .frame(width: compWidth/2, height: 30)
         }
     }
}

Or, for a more elegant approach you could look into GeometryReader.

edited Jul 01 '19 at 09:31

answered Jul 01 '19 at 09:17

Bogdan Farca

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In the second code I should put between the { } the dimension that I want? – Vipera74 Jul 01 '19 at 09:24
@Vipera74: Yes, you could even compute it with "regular" swift code. – Bogdan Farca Jul 01 '19 at 09:26
Cool, let me know if it worked (by accepting my answer :-) – Bogdan Farca Jul 01 '19 at 09:27
Btw, the `private var ...` part should be put outside the `body` of the view. – Bogdan Farca Jul 01 '19 at 09:29
"Attribute 'private' can only be used in a non-local scope" I get this error and a couple more errors – Vipera74 Jul 01 '19 at 09:30
Oh you wrote while I was writing – Vipera74 Jul 01 '19 at 09:30
Sorry, forgot to tick your answer – Vipera74 Jul 01 '19 at 18:20

How to access parents frame in SwiftUI

1 Answers1