[SwiftUI 开发] 显式动画和隐式动画

隐式动画

隐式动画通过修改modifier参数，每当视图的某个 animatable 参数改变时，SwiftUI 会动画化呈现旧值到新值的变化。

    @State private var animationAmount: Bool = false
    
    var body: some View {
        Image("turtlerock")
            .frame(width: 300, height: 300, alignment: .center)
            .clipShape(Circle())
            .overlay(Circle().stroke(.white,lineWidth: 4))
            .shadow( radius: 10)
            .rotation3DEffect(Angle(degrees: animationAmount ? 180 : 0), axis: (x: 0.0, y: 1.0, z: 0.0))
            .animation(.interpolatingSpring(stiffness: 30, damping: 3))
            .onTapGesture {
                self.animationAmount.toggle()
            }
    }

显式动画

显式动画通过 withAnimation { ... } 闭包指定。动画显示的内容都在闭包中描述。

    @State private var animationAmount: Bool = false
    
    var body: some View {
        Image("turtlerock")
            .frame(width: 300, height: 300, alignment: .center)
            .clipShape(Circle())
            .overlay(Circle().stroke(.white,lineWidth: 4))
            .shadow( radius: 10)
            .rotation3DEffect(Angle(degrees: animationAmount ? 180 : 0), axis: (x: 0.0, y: 1.0, z: 0.0))
            .onTapGesture {
                withAnimation(.interpolatingSpring(stiffness: 30, damping: 3)) {
                    self.animationAmount.toggle()
                } 
            }
    }