swiftui, animation applied to parent effect child animation

Question

RectangleView has a slide animation, his child TextView has a rotation animation. I suppose that RectangleView with his child(TextView) as a whole slide(easeInOut) into screen w

Answer 1

If there are several simultaneous animations the generic solution (in majority of cases) is to use explicit state value for each.

So here is a corrected code (tested with Xcode 12.1 / iOS 14.1, use Simulator or Device, Preview renders some transitions incorrectly)

struct AnimationTestView: View {
    @State private var go = false
    var body: some View {
        VStack {
            Button("Go!") {
                go.toggle()
            }
                VStack {      // container needed for correct transition !!
                    if go {
                         RectangleView()
                              .transition(.slide)
                    }
                }.animation(.easeInOut, value: go)    // << here !!
        }.navigationTitle("Animation Test")
    }
}

struct RectangleView: View {
    var body: some View {
        Rectangle()
            .frame(width: 100, height: 100)
            .foregroundColor(.pink)
            .overlay(TextView())
    }
}

struct TextView: View {
    @State private var animationRotating: Bool = false
    let animation = Animation.linear(duration: 3.0).repeatForever(autoreverses: false)
    
    var body: some View {
        Text("Test")
            .foregroundColor(.blue)
            .rotationEffect(.degrees(animationRotating ? 360 : 0))
            .animation(animation, value: animationRotating)          // << here !!
            .onAppear { animationRotating = true }
            .onDisappear { animationRotating = false }
    }
}