如何在 SwiftUI 中使用 Lottie Button 动画启用动作？

Question

我有一个简单的项目，它是运行点击按钮时的 Lottie 动画。

struct ContentView: View {

@State var number = 0
@State var toogleValue : Bool = false

var body: some View {
    ZStack {
        Color.green.opacity(0.2)
        ZStack {
            LottieButton(filename: "17247-happy-flower")
               .frame(width: 200)
               .onTapGesture {
                    self.number += 1
            }
            Text("number = \(self.number)")
            .offset( y: 150)
        }
    }.edgesIgnoringSafeArea(.all)
}
}

我想要实现的是：每当用户点击按钮时，动画应该开始并且数字计数器应该增加 1。

现在发生了什么：计数器加 1 但动画没有播放。

我尝试了什么：当我评论 // onTapGesture {self.number += 1} 动画工作正常，但计数器不工作。

这是 Lottie 按钮：

  struct LottieButton: UIViewRepresentable {
/// Create a button.
let animationButton = AnimatedButton()
var filename = "LottieLogo2"

func makeUIView(context: UIViewRepresentableContext<LottieButton>) -> UIView {
let view = UIView()

let animation = Animation.named(filename)
animationButton.animation = animation
animationButton.contentMode = .scaleAspectFit

animationButton.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(animationButton)

animationButton.clipsToBounds = false
   /// Set animation play ranges for touch states
animationButton.setPlayRange(fromMarker: "touchDownStart", toMarker: "touchDownEnd", event: .touchUpInside)
 //  animationButton.setPlayRange(fromMarker: "touchDownEnd", toMarker: "touchUpCancel", event: .touchUpOutside)
 //  animationButton.setPlayRange(fromMarker: "touchDownEnd", toMarker: "touchUpEnd", event: .touchUpInside)
                                 
NSLayoutConstraint.activate([
    animationButton.heightAnchor.constraint(equalTo: view.heightAnchor),
    animationButton.widthAnchor.constraint(equalTo: view.widthAnchor),
])

return view
}

func updateUIView(_ uiView: UIView, context: UIViewRepresentableContext<LottieButton>) {
         
}
}

我假设问题是由于视图的层次结构引起的，但我不确定。

Answer 1

您需要接受可以与 UIViewRepresentable 一起使用的 Coordinator。

通过 Coordinator class 它允许您将目标添加到 animationView。目标和 Objective-C 暴露的函数只能添加到 classes。这意味着您可以在点击动画时执行任何操作。

我们向 LottieButton 结构传递两个参数 filename 和 action。该动作基本上是一个闭包，允许我们传递一段稍后将执行的代码。

我们通过传递对我们正在创建的 LottieButton 的引用来设置 Coordinator，然后我们添加目标。这需要在调用 super.init 之后添加，因为我们需要用户 self.

import SwiftUI
import Lottie

struct LottieButton: UIViewRepresentable {

    typealias UIViewType = UIView
    let animationView = AnimatedButton()
    let filename: String
    let action: () -> Void

    func makeUIView(context: UIViewRepresentableContext<LottieButton>) -> UIView {
        let view = UIView()

        let animation = Animation.named(filename)
        animationView.animation = animation
        animationView.contentMode = .scaleAspectFit

        animationView.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(animationView)

        NSLayoutConstraint.activate([
            animationView.widthAnchor.constraint(equalTo: view.widthAnchor),
            animationView.heightAnchor.constraint(equalTo: view.heightAnchor),
        ])

        return view
    }

    func updateUIView(_ uiView: UIView, context: UIViewRepresentableContext<LottieButton>) {

    }

    func makeCoordinator() -> Coordinator {
        Coordinator(self)
    }


    class Coordinator: NSObject {
        let parent: LottieButton

        init(_ parent: LottieButton) {
            self.parent = parent
            super.init()
            parent.animationView.addTarget(self, action: #selector(touchUpInside), for: .touchUpInside)
        }

        // this function can be called anything, but it is best to make the names clear
        @objc func touchUpInside() {
            parent.action()
        }
    }
}

这意味着我们可以在 ContentView 中执行以下操作。我们的动作参数现在可以在点击按钮时执行我们想要的任何操作。

struct ContentView: View {

    @State private var tapped: Int = 0

    var body: some View {
        VStack {
            LottieButton(filename: "loading", action: {
                print("tapped")
                tapped += 1
            })
            .frame(width: 200, height: 200)

            Text("tapped count \(tapped)")
        }
    }
}

它正在运行：

如何在 SwiftUI 中使用 Lottie Button 动画启用动作？

How to enable action with Lottie Button animation in SwiftUI?

swift

animation

swiftui

lottie