SwiftUI - 从外部调用视图中的函数

如何解决SwiftUI - 从外部调用视图中的函数

是否可以从外部调用 View 的 func。
我这样试过，但没有成功。

@main
struct CallFromOutsideApp: App {
  var body: some Scene {
    WindowGroup {
      ContentView()
    }
  }
}

struct ContentView: View {
  var body: some View {
    vstack{
      SubView()
      Button("Call alterX in ContentView"){
        // How to call alterX in SubView????
      }
    }
    .padding()
  }
}

struct SubView: View {
  @State var x = "Status A"
  
  var body: some View {
    vstack{
      Text("Status: \(x)")
      Button("Call alterX in SubView"){ alterX()
      }
    }
    .padding()
  }
  
  func alterX(){
    x = "Status B"
  }
}

解决方法

编辑

您不应从 SubView 控制 @State 的 ContentView。相反，将 @State 放入 ContentView 并将其传递给 @Binding 中的 SubView。

struct ContentView: View {
    @State var x = "Status A"
    var body: some View {
        VStack{
            
            SubView(x: $x) /// pass in the binding
            
            Button("Alter X in ContentView"){
                x = "Status B"
            }
        }
        .padding()
    }
}

struct SubView: View {
    @Binding var x: String
    
    var body: some View {
        VStack{
            Text("Status: \(x)")
            Button("Alter X in SubView") {
                x = "Status B"
            }
        }
        .padding()
    }
}

---

您可以将 SubView 存储在属性中。喜欢

struct ContentView: View {
  let subView = SubView()
  var body: some View {
    VStack{

      subView /// like this

      Button("Call alterX in ContentView"){
        subView.alterX() /// call it
      }
    }
    .padding()
  }
}

struct SubView: View {
  @State var x = "Status A"
  
  var body: some View {
    VStack{
      Text("Status: \(x)")
      Button("Call alterX in SubView"){ alterX()
      }
    }
    .padding()
  }
  
  func alterX(){
    x = "Status B"
  }
}