如何在 Widget 预览 SwiftUI iOS 14 中加载 WKWebView答案

【问题标题】：How to load WKWebView in Widget preview SwiftUI iOS 14如何在 Widget 预览 SwiftUI iOS 14 中加载 WKWebView
【发布时间】：2021-01-21 01:02:52
【问题描述】：

如何在 swiftui ios 14 中加载 wkwebview关于swiftui以及我很好奇苹果是否允许这件事？

import WidgetKit
import SwiftUI
import WebKit
import Photos

struct Provider: TimelineProvider {
    func placeholder(in context: Context) -> SimpleEntry {
        SimpleEntry(date: Date())
    }

    func getSnapshot(in context: Context, completion: @escaping (SimpleEntry) -> ()) {
        let entry = SimpleEntry(date: Date())
        completion(entry)
    }

    func getTimeline(in context: Context, completion: @escaping (Timeline<Entry>) -> ()) {
        var entries: [SimpleEntry] = []

        let currentDate = Date()
        for hourOffset in 0 ..< 5 {
            let entryDate = Calendar.current.date(byAdding: .hour, value: hourOffset, to: currentDate)!
            let entry = SimpleEntry(date: entryDate)
            entries.append(entry)
        }

        let timeline = Timeline(entries: entries, policy: .atEnd)
        completion(timeline)
    }
}

struct SimpleEntry: TimelineEntry {
    let date: Date
}

struct WebWidgetEntryView : View {
    var entry: Provider.Entry
     var body: some View {
        WebView(request: URLRequest(url: URL(string: "https://www.apple.com")!))
    }      
}

@main
struct WebWidget: Widget {
    let kind: String = "WebWidget"

    var body: some WidgetConfiguration {
        StaticConfiguration(kind: kind, provider: Provider()) { entry in
            WebWidgetEntryView(entry: entry)
        }
        .configurationDisplayName("My Widget")
        .description("This is an example widget.")
    }
}

struct WebWidget_Previews: PreviewProvider {    
    static var previews: some View {
        WebView(request: URLRequest(url: URL(string: "https://www.apple.com")!))
    }

}
    
struct ActivityIndicator: UIViewRepresentable {

    @Binding var isAnimating: Bool
    let style: UIActivityIndicatorView.Style

    func makeUIView(context: UIViewRepresentableContext<ActivityIndicator>) -> UIActivityIndicatorView {
        return UIActivityIndicatorView(style: style)
    }

    func updateUIView(_ uiView: UIActivityIndicatorView, context: UIViewRepresentableContext<ActivityIndicator>) {
        isAnimating ? uiView.startAnimating() : uiView.stopAnimating()
    }
}

struct LoadingView<Content>: View where Content: View {

    @Binding var isShowing: Bool
    var content: () -> Content

    var body: some View {
        GeometryReader { geometry in
            ZStack(alignment: .center) {

                self.content()
                    .disabled(self.isShowing)
                    .blur(radius: self.isShowing ? 3 : 0)

                VStack {
                    Text("Loading...")
                    ActivityIndicator(isAnimating: .constant(true), style: .large)
                }
                .frame(width: geometry.size.width / 2,
                       height: geometry.size.height / 5)
                .background(Color.secondary.colorInvert())
                .foregroundColor(Color.primary)
                .cornerRadius(20)
                .opacity(self.isShowing ? 1 : 0)

            }
        }
    }

}


struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        WebView(request: URLRequest(url: URL(string: "https://www.apple.com")!))
    }
}
struct WebView : UIViewRepresentable {
    
    let request: URLRequest
    
    func makeUIView(context: Context) -> WKWebView  {
        return WKWebView()
    }
    
    func updateUIView(_ uiView: WKWebView, context: Context) {
        uiView.load(request)
    }
    
}

【问题讨论】：

标签： swift swiftui ios14 widgetkit

【解决方案1】：

很遗憾，您可以在小部件中使用的视图存在一些限制。

由于小部件视图不允许交互（Link 除外），因此您不能在小部件中使用 ScrollView。而且我怀疑 WKWebView 是建立在 UIScrollView 之上的。

如果您想显示一些 URL 内容，您有两种选择：

在 TimelineProvider 中获取数据并传递给条目
按照this answer 中的建议使用Data(contentsOf: url)。

【讨论】：