如何在SwiftUI列表中使用自定义视图平滑地扩展行单元格? [英] How to expand a row cell smoothly with a custom view in SwiftUI List?

问题描述

我正在尝试在轻击手势上扩展行单元格(这是一个自定义视图). 必须增加像元的高度，并在扩展区域中移动按钮. 但是我得到了下面的跳跃动画效果.按下的蓝卡应保持稳定，但会跳来跳去.

I am trying to expand a row cell (which is a custom view) on tap gesture. The cell height has to be increased and a button is being moved in the expanded area. But I get the following jumpy animation effect. The pressed blue card shall remain steady but instead it jumps around.

简单的代码可以重现这个跳动的动画:

Simple Code to reproduce this jumpy animation:

import SwiftUI

struct ContentView: View {
    var body: some View {
        VStack {
            Text("Hello, World!")
            List {
                Detail(isExpanded: false)
                Detail(isExpanded: false)
                Detail(isExpanded: false)
            }
        }
    }
}
struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}



struct Detail: View {
    @State var isExpanded :Bool
    var body: some View {
        ZStack {
            ZStack {
                RoundedRectangle(cornerRadius: 8)
                .fill(Color(red: 0.0, green: 1.0, blue: 1.0, opacity: 1.0)).frame(height: 115)
                Text("Hello, World!")
            }.zIndex(3).frame(height: 115).contentShape(Rectangle()).onTapGesture {
                withAnimation {
                    self.isExpanded.toggle()
                }
            }
            Button(action: {
            }) {
                ZStack {
                    RoundedRectangle(cornerRadius: 50)
                        .fill(Color(red: 1.0, green: 0.0, blue: 1.0, opacity: 1.0)).frame(height: 70)
                        .cornerRadius(8)
                        .shadow(radius: 3)
                        Text("Test")
                }
            }.padding([.leading, .trailing], 12)
                .padding(.top, 6)
                .frame(height: 70)
                .buttonStyle(BorderlessButtonStyle())
                .offset(y: self.isExpanded ? 0 : 40)
                .disabled(!self.isExpanded)
        }.frame(height: self.isExpanded ? 120 : 200)
    }
}

我非常感谢您提供有关如何解决此问题的任何提示或提示.

I am grateful for any tips or hints on how to smoothe this out.

编辑

单击时，hello world卡应保持在单元格本身顶部的对齐状态.像这样:

When clicked the hello world card should remain aligned at the top in the cell itself. Like so:

推荐答案

只需从此我的解决方案中使用可动画修饰的

Just use animatable modifier from this my solution

通过Xcode 11.4/iOS 13.4测试

Tested with Xcode 11.4 / iOS 13.4

ZStack {
 // .. other your code here
}
.modifier(AnimatingCellHeight(height: self.isExpanded ? 120 : 200))

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