在Canvas SwiftUI上崩溃

Question

我正在用新的iOS框架SwiftUI实现一个小应用程序。我@EnvironmentObject用来绑定数据进行查看。一切正常，但Canvas崩溃并没有显示任何内容。为什么？

struct CompetitionsListSwiftUIView : View {

    @EnvironmentObject var competitionsViewModel: CompetitionsViewModel

    var body: some View {
        List(self.competitionsViewModel.competitions.identified(by: \.id)) { competition in
                CompetitionCellSwiftUIView(competition: competition)
            }
    }
}

#if DEBUG
struct CompetitionsListSwiftUIView_Previews : PreviewProvider {
    static var previews: some View {
        CompetitionsListSwiftUIView()
    }
}
#endif

画布的错误消息是这样的：

Error Domain=render service Code=12 "Rendering service was interrupted" UserInfo={NSLocalizedDescription=Rendering service was interrupted}

Answer 1

尝试将环境对象添加到预览中：

#if DEBUG
struct CompetitionsListSwiftUIView_Previews : PreviewProvider {
    static var previews: some View {
        CompetitionsListSwiftUIView()
          .environmentObject(CompetitionsViewModel())
    }
}
#endif