如何使用SwiftUI对一系列图像进行动画处理？

Question

如何使用SwiftUI框架对一系列图像(比如从Frame-1.png到Frame-6)进行动画处理？

我试着创建一个“图像”数组。然后，我将图像(with: images，duration: 1.0)方法赋值给一个名为"animatedImage“的变量。最后，我在"ContentView.swift”的"body“中尝试了UIImage.animatedImage(uiImage: animatedImage)。

var images: [UIImage]! = [UIImage(named: "Sequence/frame-1")!,
                          UIImage(named: "Sequence/frame-2")!,
                          UIImage(named: "Sequence/frame-3")!,
                          UIImage(named: "Sequence/frame-4")!,
                          UIImage(named: "Sequence/frame-5")!,
                          UIImage(named: "Sequence/frame-6")!
]

let animatedImage : UIImage! = UIImage.animatedImage(with: images, duration: 1.0)

//////Then in the ContentView.swift I've tried this code:

struct ContentView : View {
    var body: some View {

        Image(uiImage: animatedImage)

    }
}

当我运行程序时，它只显示第一帧，但我希望看到帧的动画

Answer 1

公认的答案非常有效，但bhagyash ingale提到的不幸问题使其很难使用。如果可以通过协议或其他方式重用Image的特定方法，这将是很有用的。我有一个非常差的，也许是巨大的加农炮为这个苍蝇解决方案，也许它会更容易，但现在…

class LoadingTimer {

    let publisher = Timer.publish(every: 0.1, on: .main, in: .default)
    private var timerCancellable: Cancellable?

    func start() {
        self.timerCancellable = publisher.connect()
    }

    func cancel() {
        self.timerCancellable?.cancel()
    }
}

struct LoadingView: View {

    @State private var index = 0

    private let images = (0...7).map { UIImage(named: "Image-\($0).jpg")! }
    private var timer = LoadingTimer()

    var body: some View {

        return Image(uiImage: images[index])
            .resizable()
            .frame(width: 100, height: 100, alignment: .center)
            .onReceive(
                timer.publisher,
                perform: { _ in
                    self.index = self.index + 1
                    if self.index >= 7 { self.index = 0 }
                }
            )
            .onAppear { self.timer.start() }
            .onDisappear { self.timer.cancel() }
    }
}

我不喜欢这样，但它可以完成工作，并依赖于Image。

Answer 2

不带组合的版本

import SwiftUI

struct AnimatingImage: View {
    let images: [Image]

    @ObservedObject private var counter = Counter(interval: 0.05)
        
    var body: some View {
        images[counter.value % images.count]
    }
}

private class Counter: ObservableObject {
    private var timer: Timer?

    @Published var value: Int = 0
    
    init(interval: Double) {
        timer = Timer.scheduledTimer(withTimeInterval: interval, repeats: true) { _ in self.value += 1 }
    }
}

你可以使用它

struct LoadingView: View {
    private let images = (1...20).map { String(format: "i_%02d", $0) }.map { Image($0) }
    
    var body: some View {
        AnimatingImage(images: images)
    }
}

Answer 3

你有没有试过制作自己的视图包装器？

如下所示：

struct AnimatedImage: UIViewRepresentable {
    func makeUIView(context: Self.Context) -> UIImageView {
        return UIImageView(image: animatedImage)
    }

    func updateUIView(_ uiView: UIImageView, context: UIViewRepresentableContext<AnimatedImage>) {
    }
}

用法如下：

struct ContentView : View {
    var body: some View {
        AnimatedImage()
    }
}

不确定这是否能解决你的问题，至少它不再是一个静态图像:D

在Xcode Beta 2模拟器上试用过。