SwiftUI @Binding更新不会刷新视图 [英] SwiftUI @Binding update doesn't refresh view

问题描述

我觉得我缺少一些非常基本的东西，但是此示例SwiftUI代码在单击按钮时不会修改视图(尽管进行了绑定更新)

I feel like I'm missing something very basic, but this example SwiftUI code will not modify the view (despite the Binding updating) when the button is clicked

教程我阅读过，建议这是使用绑定的正确方法，视图应自动刷新

Tutorials I have read suggest this is the correct way to use a binding and the view should refresh automatically

import SwiftUI

struct ContentView: View {
    @Binding var isSelected: Bool

    var body: some View {
        Button(action: {
            self.isSelected.toggle()
        }) {
            Text(isSelected ? "Selected" : "Not Selected")
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    @State static var selected: Bool = false

    static var previews: some View {
        ContentView(isSelected: $selected)
    }
}

推荐答案

您没有误解任何东西.当基础@State更改时，使用@Binding的View将更新，但是 @State必须在视图层次结构中定义.(否则您可以绑定到发布者)

You have not misunderstood anything. A View using a @Binding will update when the underlying @State change, but the @State must be defined within the view hierarchy. (Else you could bind to a publisher)

下面，我将您的ContentView的名称更改为OriginalContentView，然后在包含您的原始内容视图的新ContentView中定义了@State.

Below, I have changed the name of your ContentView to OriginalContentView and then I have defined the @State in the new ContentView that contains your original content view.

import SwiftUI

struct OriginalContentView: View {
    @Binding var isSelected: Bool

    var body: some View {
        Button(action: {
            self.isSelected.toggle()
        }) {
            Text(isSelected ? "Selected" : "Not Selected")
        }
    }
}

struct ContentView: View {
    @State private var selected = false

    var body: some View {
       OriginalContentView(isSelected: $selected)
    }
}



struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

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