Question

我正在尝试在收到一些数据后更新SwiftUI视图。我更新了actions: <Widget>[ PopupMenuButton<String>( icon: Container( child: ClipOval( child: Align( heightFactor: 1, widthFactor: 1, child: Image.network(googleUserUrl), ), ) ),属性的值，但这没有任何作用。似乎该值实际上根本没有更新。我也不太幸运尝试使用@State。

这是我正在尝试的游乐场示例

@Binding

此打印

import SwiftUI

struct SomeView: View {
  // I've seen example of ObservableValue using classes, but as much as possible
  // I'd like to use immutable structs for my state.
  struct ViewModel {
    let foo: [Int]
  }

  @State var viewModel: ViewModel

  init(_ viewModel: ViewModel) {
    self._viewModel = .init(initialValue: viewModel)
  }

  var body: some View {
    Text(displayText)
  }

  var displayText: String {
    print("displaying \(viewModel.foo.count) elements")
    return "\(viewModel.foo.count)"
  }
}

let view = SomeView(.init(foo: []))
print("will set new viewModel")
view.viewModel = .init(foo: [1, 2, 3]) // Looks like this doesn't do anything
print("did set new viewModel")
print("View now has \(view.viewModel.foo.count) elements")

我希望看到

displaying 0 elements
will set new viewModel
displaying 0 elements
did set new viewModel
View now has 0 elements

更新SwiftUI的视图状态不会更新状态或视图

0 个答案: