UPGRADE YOUR SKILLS: Learn advanced Swift and SwiftUI on Hacking with Swift+! >>

SOLVED: Animated view with rotation, has problem as it moves up and down

Forums > SwiftUI

Ok, so I've a simple loader animation, but when I present the animation from a NavigationLink, just for showcase, the view moves up and down, it works fine in the view preview, but simulator and devices have this issue.

struct SystemDesignView: View {

    var body: some View {
        NavigationStack  {
            List {
                Section("Animated Components WIP") {
                    NavigationLink {
                        LoaderView()
                    } label: {
                        Text("Loader")
                    }
                }
                .navigationTitle("System Design")
            }
        }
    }
}

And this is the animated view:

struct LoaderView: View {
    @State private var rotationAngle: Angle = .degrees(0)
    private var lineWidth = 2.0
    private var lenght = 42.0

    var body: some View {
        ZStack {
            // Full circle
            Circle()
                .strokeBorder(Color.electric.opacity(0.1), lineWidth: lineWidth)
                .frame(width: lenght, height: lenght)
                .background(Color.clear)

            // Quarter circle
            Circle()
                .trim(from: 0.0, to: 0.25)
                .stroke(Color.electric.opacity(1.0), style: StrokeStyle(lineWidth: lineWidth, lineCap: .round, lineJoin: .round)) // Rounded corners
                .frame(width: lenght - lineWidth, height: lenght - lineWidth)
                .rotationEffect(rotationAngle, anchor: .center)

        }
        .onAppear() {
            withAnimation(Animation.linear(duration: 1.0).repeatForever(autoreverses: false)) {
                rotationAngle = .degrees(360)
            }
        }
    }
}

struct LoaderView_Previews: PreviewProvider {
    static var previews: some View {
        LoaderView()
    }
}

Any idea how to fix it?, thank you

Here is a video https://github.com/Edhoru/MyParty/blob/main/Simulator%20Screen%20Recording%20-%20iPhone%2014%20Pro%20-%202023-05-11%20at%2008.51.07.mp4

1      

Hi,

I found 2 work arounds to this problem, only tested on simulator,

  1. is to wrap the withAnimation in a DispatchQueue.main.async
  2. is to change from a onApear to a task
.onAppear {
    DispatchQueue.main.async {
        withAnimation(Animation.linear(duration: 1.0).repeatForever(autoreverses: false)) {
            rotationAngle = .degrees(360)
        }
    }
}
.task {
    withAnimation(Animation.linear(duration: 1.0).repeatForever(autoreverses: false)) {
        rotationAngle = .degrees(360)
    }
}

2      

Hacking with Swift is sponsored by RevenueCat

SPONSORED Take the pain out of configuring and testing your paywalls. RevenueCat's Paywalls allow you to remotely configure your entire paywall view without any code changes or app updates.

Learn more here

Sponsor Hacking with Swift and reach the world's largest Swift community!

Reply to this topic…

You need to create an account or log in to reply.

All interactions here are governed by our code of conduct.

 
Unknown user

You are not logged in

Log in or create account
 

Link copied to your pasteboard.