Swift - 绑定更改未调用 didSet 属性

Question

My problem:

I want to call a function when my customView clicked

So I use @State variable to observe the click action from my custom view. But the problem is my value changed but didSet function not triggered

My code:

Main struct:

   @State var buttonClicked : Bool = false {
        didSet{
          needToCallMyFunction() // not triggered 
        }
    }

Custom struct:(for my customview)

@Binding var isClicked : Bool

someview
.onTapGesture(perform: {
            print("custom clicked")
            isClicked.toggle()
        })

Answer 1

Use instead in main view .onChange(of:) modifier, like

  SomeView()
    .onChange(of: buttonClicked) { _ in
       self.needToCallMyFunction()
    }

Update: variant for SwiftUI 1.0 / iOS 13+

import Combine   // needed to use Just

...

  SomeView()
    .onReceive(Just(buttonClicked)) { _ in
       self.needToCallMyFunction()
    }

Answer 2

Asperi solution working fine.

But it have one bug in lower versions. It called multiple times

I found another solution

SomeView(buttonClicked: 
             Binding(get: { self.buttonClicked },
                     set: { self.buttonClicked = $0
                               print("your action here ")
                }))