详解iOS14 Widget 开发相关及易报错地方处理

// Provider，顾名思义为小组件提供信息得一个struct
struct Provider: TimelineProvider {
  public typealias Entry = SimpleEntry
  
  // 编辑屏幕时，左上角选择添加小组件时候，第一次展示小组件会走这个方法
  public func snapshot(with context: Context, completion: @escaping (SimpleEntry) -> ()) {
    
  }

  // 这个方法内可以进行网络请求，拿到的数据保存在对应的 entry 中，调用 completion 之后会到刷新小组件
  public func timeline(with context: Context, completion: @escaping (Timeline<Entry>) -> ()) {
    // 例如这是一个网络请求
    Network.request { data in
      let entry = SimpleEntry(date: renderDate, data: data)
      let timeline = Timeline(entries: [entry], policy: .after(nextRequestDate))
      completion(timeline)
    }
  }
}

// 我的理解是就是存储小组件的数据的一个东西
struct SimpleEntry: TimelineEntry {
  let date: Date
  let data: Data
}

// 这个是一个默认视图，例如网络请求失败、发生未知错误、第一次展示小组件都会展示这个view
struct PlaceholderView : View {
  
}

// 这个是我们需要布局小组件长什么样子的view
struct StaticWidgetEntryView : View {
  
}

@main
struct StaticWidget: Widget {
  private let kind: String = "StaticWidget"

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

@main
struct MainWidgets: WidgetBundle {

  @WidgetBundleBuilder
  var body: some Widget {
    Widget1()
    Widget2()
  }

}

@main
struct MainWidget: Widget {
  private let kind: String = "MainWidget"

  public var body: some WidgetConfiguration {
    IntentConfiguration(kind: kind, intent: XYConfigurationIntent.self, provider: Provider(), placeholder: PlaceholderView()) { entry in
      IntentWidgetEntryView(entry: entry)
    }
    .configurationDisplayName("My Widget")
    .description("This is an example widget.")
  }
}

@ViewBuilder
var body: some View {
  ZStack {
    AvatarView(entry.character)
      .widgetURL(url)
      .foregroundColor(.white)
  }
  .background(Color.gameBackground)
}

struct RecipeView: View {
  let recipe: RecipeModel
  
  var body: some View {
    Link(destination: URL(string: "你的网址")!) {
      HStack {
        WebImageView(imageUrl: recipe.squareImageUrl)
          .frame(width: 65, height: 65)
        
        Text(recipe.adjName + recipe.name)
          .font(.footnote)
          .bold()
          .foregroundColor(.black)
          .lineLimit(3)
      }
    }
  } 
}

func application(_ app: UIApplication, open url: URL, options: [UIApplication.OpenURLOptionsKey : Any] = [:]) -> Bool {
    
}

Struct Model {
 ...
 let image: UIImage
}

func timeline(with context: Context, completion: @escaping (Timeline<LFPlanEntry>) -> ()) {
  Network.request { data in
    // 解析图片
    var image: UIImage? = nil
    if let imageData = try? Data(contentsOf: url) {
      image = UIImage(data: imageData)
    }
    let model = Model(image: image ?? defalutImage) // 这里给个默认图片
    let entry = SimpleEntry(date: entryDate, data: model)
    let timeline = Timeline(entries: [entry], policy: .atEnd)
    completion(timeline)
  }
}

Struct WidgetView: View {
  
  let model: Model

  @ViewBuilder
  var body: some View {
    Image(uiImage: model.image)
          .resizable()
  }

}

struct WidgetView : View {
  
  let model: Model

  @State private var remoteImage : UIImage? = nil
  
  let defaultImage = UIImage(named: "default")!
  
  var body: some View {
    Image(uiImage: self.remoteImage ?? defaultImage)
      .onAppear(perform: fetchRemoteImage)
  }
  
  func fetchRemoteImage() {
    guard let url = URL(string: model.url) else { return }
    URLSession.shared.dataTask(with: url){ (data, response, error) in
      if let image = UIImage(data: data!){
        self.remoteImage = image
      } else {
        print(error ?? "")
      }
    }.resume()
  }
}