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How to create basic animations

Paul Hudson @twostraws September 18th 2019

Updated for Xcode 12.0

SwiftUI has built-in support for animations with its animation() modifier. To use this modifier, place it after any other modifiers for your views, and tell it what kind of animation you want.

For example, this code creates a button that increases its scale effect by 1 each time it’s pressed:

struct ContentView: View {
    @State private var scale: CGFloat = 1

    var body: some View {
        Button(action: {
            self.scale += 1
        }) {
            Text("Tap here")
                .scaleEffect(scale)
                .animation(.linear)
        }
    }
}

You can specify a precise duration for the animation if you want. For example, this animates the scale effect over three seconds:

Text("Tap here")
    .scaleEffect(scale)
    .animation(.linear(duration: 3))

Instead of simple linear animations, you can specify a curve from .easeIn, .easeOut, .easeInOut, or use .timingCurve to specify your own control points.

For example, this animates the scale effect so that it starts slow and gets faster:

Text("Tap here")
    .scaleEffect(scale)
    .animation(.easeIn)

You can animate many other modifiers, such as 2D and 3D rotation, opacity, border, and more. For example, this makes a button that spins around and increases its border every time it’s tapped:

struct ContentView: View {
    @State private var angle: Double = 0
    @State private var borderThickness: CGFloat = 1

    var body: some View {
        Button(action: {
            self.angle += 45
            self.borderThickness += 1
        }) {
            Text("Tap here")
                .padding()
                .border(Color.red, width: borderThickness)
                .rotationEffect(.degrees(angle))
                .animation(.easeIn)
        }
    }
}

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How to create basic animations

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