发布值上的SwiftUI toggle()函数停止使用Swift 5.2触发didSet [英] SwiftUI toggle() function on Published values stopped triggering didSet with Swift 5.2

问题描述

我刚刚将Xcode从11.3更新为11.4，用SwiftUI编写的项目的行为开始有所不同.我曾经为布尔值调用 toggle()函数，它曾经触发过 didSet 属性观察器，但是，它不再起作用了.

I have just updated my Xcode to 11.4 from 11.3 and my project written in SwiftUI started to behave differently. I used to call toggle() function for boolean values and it used to trigger didSet property observer, however, it is not working any more.

假设我们有一个名为 isSettingOn 的 State 属性.我曾经这样称呼过:

Let' say we have a State property called isSettingOn. I used to call this:

isSettingOn.toggle()

正在触发该属性的 didSet 观察者.现在，只有当我打电话给我时:

which was triggering didSet observer of the property. Now, only if I call this:

isSettingOn = true

正在工作.

我的项目都基于这种行为，现在这种变化基本上破坏了一切.有人知道我在这里实际上是否做错了什么?

My projects are all based on this behaviour and now this change basically broke everything. Does anyone know if I am actually doing anything wrong here?

添加了演示代码:

struct ContentView: View {

    @State var isSettingOn: Bool = true {
        didSet {
            print("didSet isSettingOn")
        }
    }

    var body: some View {
        Button(action: {
            self.isSettingOn = true // will trigger didSet
            self.isSettingOn.toggle() // won't trigger didSet
        }) {
            Text("Toggle isSettingOn")
        }
    }
}

推荐答案

这是 Xcode 11.4和11.4.1 中的错误，并已在 Xcode 11.5(Beta)中修复带有 Swift 5.2.4 .

This was a bug in Xcode 11.4 and 11.4.1 and it was fixed in Xcode 11.5 (Beta) with Swift 5.2.4.

这篇关于发布值上的SwiftUI toggle()函数停止使用Swift 5.2触发didSet的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！