有没有办法用 withAnimation(...?

问题描述

由于某种原因，SwiftUi withAnimation 在 navigationBarItems 修饰符中不起作用。有解决办法吗？我知道视图上的 .animation 修饰符是动画作品，但这对于更复杂的动画来说还不够。

我想知道以前没有人问过这个问题，我想更多的人有这个问题。有人知道解决方法吗？

这里有一个例子：https://drive.google.com/file/d/1d2Ud2xxhVCJBCfBQwlZ1mJgTnyNpxc_-/view?usp=sharing

    struct TestView: View {
    
      @State var red = true
    
      var body: some View {
        NavigationView {

            vstack {
                HStack {
                    Rectangle()
                        .fill(red ? Color.red : .blue)
                        .onTapGesture {
                         
                         
                         withAnimation(Animation.easeIn(duration: 1),{
                                
                            red.toggle()
                            })
                        }
                    
                }
                
                
                Spacer()
                
            }
            
            
                
            .navigationTitle("Test")
            .navigationBarItems(leading:
                                    HStack {
                                        Rectangle()
                                            .fill(red ? Color.red : .blue)
                                            .onTapGesture {
                                             
                                             
                                                   withAnimation(Animation.easeIn(duration: 1),{
                                                    
                                                red.toggle()
                                                })
                                            }
                                    }
                                    
            )
        }
        
       }
    }


    struct TestView_Previews: PreviewProvider {
    
      static var previews: some View {
        TestView()
      }
    }
    

    ```


Edit: Aspires solution is valid for my original question. For some reason it still does not work in the context I am using it in:

    struct ContentView: View {
    
    
    @State var redColor = false

    var body: some View {
        NavigationView {
            
            Button("change Color",action: {
                withAnimation(Animation.easeIn(duration: 1),{
                    redColor.toggle()
                })
            })
            
            .navigationTitle("Test")
            .navigationBarItems(leading:
                                    RectView(redColor: $redColor)
            )
        }

     }
}


struct RectView: View {
    
    @State var red: Bool = false
    @Binding var redColor: Bool

    var body: some View {
        HStack {
             Rectangle()
                  .fill(red ? Color.red : .blue)
        }.onChange(of: redColor,perform: { _ in
            red.toggle()
        })
    }
}


  

解决方法

一种可能的解决方案是将依赖于状态的动画代码分离到独立视图中，如下所示。

使用 Xcode 12.4 / iOS 14.4 测试

struct TestBarAnimationView: View {

      @State var red = true

      var body: some View {
        NavigationView {
            VStack {
                RectView(red: $red)       // << here !!
                Spacer()
            }
            .navigationTitle("Test")
            .navigationBarItems(leading:
                RectView(red: $red)       // << here !!
            )
        }

       }
    }


struct RectView: View {
    @Binding var red: Bool

    var body: some View {
        HStack {
             Rectangle()
                  .fill(red ? Color.red : .blue)
                  .onTapGesture {
                    withAnimation(Animation.easeIn(duration: 1),{
                        red.toggle()
                        })
                  }
        }
    }
}