iOS SwiftUI - 尝试调整 GIF 图像大小时忽略帧大小

Question

import SwiftUI
import PhotosUI
import AVKit
import Swime
import WebKit

struct GifImage: UIViewRepresentable {
    enum URLType {
        case local(String)
        case remote(URL?)

        var url: URL? {
            switch self {
                case .local(let name):
                return Bundle.main.url(forResource: name, withExtension: "gif")
                
                case .remote(let url):
                return url
            }
        }
    }

    let type: URLType
    var loaded: ((UIImageView, UIImage?) -> Void)?

    func makeUIView(context: Context) -> UIView {
        
        let view = UIImageView()
        DispatchQueue.global(qos: .background).async {
            
            if let url = type.url, let data = try? Data(contentsOf: url) {
                DispatchQueue.main.async {
                    if let image = UIImage.gif(data: data) {
                        view.image = image
                        view.contentMode = .scaleAspectFit
                        self.loaded?(view, image)
                    }
                }
            } else {
                DispatchQueue.main.async {
                    self.loaded?(view, nil)
                }
            }
        }
        return view
    }

    func updateUIView(_ uiView: UIView, context: Context) {}
}


struct VidPlay: View {
    
    @State var gifSize: CGSize?
    @State var gifHeight: CGFloat = 80

    var body: some View {
        
        VStack(spacing: 20){
            

            ZStack{

                GifImage(type: .remote(URL(string: "https://media.tenor.com/hRiPtsp-m0IAAAAM/the-simpsons-homer-simpson.gif"))) { _, image in
                  gifSize = image?.size
                }
                .frame(width: 80, height: gifHeight)

            }
            .onChange(of: gifSize) { _ in
                
                if(gifSize != nil){
                    
                    gifHeight = 80 * (gifSize!.height / gifSize!.width)
                    print(gifHeight)
                }
            }
            .frame(width: 240, height: 240)
            .background(Color.blue)

        }
    }
}

它打印出正确的

gifHeight

，但帧大小被忽略，如何解决这个问题？

Answer 1

SwiftUI 视图都可以根据

ProposedViewSize

选择自己的尺寸，并且完全可以选择比提案更大的尺寸。

.frame

仅更改建议的大小，但

UIViewRepresentable

选择了其

UIView

的固有大小。

您可以在您的

sizeThatFits

中实现

UIViewRepresentable

:

func sizeThatFits(_ proposal: ProposedViewSize, uiView: UIImageView, context: Context) -> CGSize? {
    guard let imageSize = uiView.image?.size else {
        return nil
    }
    return if let width = proposal.width, let height = proposal.height {
        CGSize(width: width, height: height)
    } else if let width = proposal.width {
        CGSize(width: width, height: width * imageSize.height / imageSize.width)
    } else if let height = proposal.height {
        CGSize(width: height * imageSize.width / imageSize.height, height: height)
    } else {
        nil
    }
}

请注意，我在

UIImageView

的签名中使用了

sizeThatFits

- 您还应该更改

makeUIView

和

updateUIView

的签名，也将

UIView

替换为

UIImageView

。