自定义页面指示器无法切换激活索引的问题求助

看起来你的自定义页面指示器遇到了状态更新不生效的问题，我帮你排查了代码里的几个关键问题，应该能解决你的困扰：

1. 子视图名称的笔误 #

你在CustomDotIndicatorView的body里调用的是CloveDotItemView，但实际定义的子视图是CustomDotItemView——这是个很容易忽略的笔误！它会导致系统找不到正确的视图实现，自然无法响应activeIndex的变化。把CloveDotItemView改成CustomDotItemView就能解决这个基础问题。

2. 不必要的双向Binding使用 #

你的CustomDotItemView只是用来展示激活/未激活状态，不需要修改外部的activeIndex，所以完全没必要用@Binding var isActive: Bool，改成普通的let isActive: Bool就足够了，这样还能避免无效的Binding定义。修改后的子视图代码：

private struct CustomDotItemView: View {
    let isActive: Bool // 替换原有的@Binding
    
    private let activeImage: some View = Image(
        "dotindicator-active", bundle: Bundle(identifier: bundleID))
        .renderingMode(.original)
        .colorMultiply(.green)
    
    private let inactiveImage: some View = Image(
        "dotindicator-inactive", bundle: Bundle(identifier: bundleID))
    
    var body: some View {
        ZStack {
            isActive ? activeImage : inactiveImage
        }
    }
}

3. 简化激活状态的传递 #

既然子视图不需要双向绑定，那在父视图里直接传递计算好的Bool值就行，不需要自定义空实现的Binding。修改CustomDotIndicatorView里的ForEach部分：

ForEach(0..<indicatorCount) { index in
    CustomDotItemView(isActive: actualActiveIndex == index)
}

另外，还要确认bundleID是你项目中正确的Bundle标识符，否则图片加载失败也可能让你误以为状态没更新。

最后附上修改后的完整代码，你可以直接替换测试：

import SwiftUI

public struct CustomDotIndicatorView: View {
    let indicatorCount: Int
    @Binding var activeIndex: Int
    let height: CGFloat
    let spacing: CGFloat
    
    public var body: some View {
        let actualActiveIndex = min(max(activeIndex, 0), indicatorCount - 1)
        return HStack(alignment: .center, spacing: spacing) {
            ForEach(0..<indicatorCount) { index in
                CustomDotItemView(isActive: actualActiveIndex == index)
            }
        }
        .frame(height: height)
    }
}

private struct CustomDotItemView: View {
    let isActive: Bool
    
    private let activeImage: some View = Image(
        "dotindicator-active", bundle: Bundle(identifier: bundleID))
        .renderingMode(.original)
        .colorMultiply(.green)
    
    private let inactiveImage: some View = Image(
        "dotindicator-inactive", bundle: Bundle(identifier: bundleID))
    
    var body: some View {
        ZStack {
            isActive ? activeImage : inactiveImage
        }
    }
}

struct CustomDotIndicatorView_Previews: PreviewProvider {
    @State static var activeIndex: Int = 0
    static let indicatorCount: Int = 5
    
    static var previews: some View {
        ZStack {
            Color.blue.opacity(0.2).ignoresSafeArea(.all)
            VStack {
                Spacer()
                HStack {
                    Button {
                        activeIndex -= 1
                    } label: {
                        Label("", systemImage: "chevron.left")
                    }
                    .padding(.leading, 48)
                    
                    Spacer()
                    
                    CustomDotIndicatorView(indicatorCount: indicatorCount, activeIndex: $activeIndex, height: 6, spacing: 12)
                    
                    Spacer()
                    
                    Button {
                        activeIndex += 1
                    } label: {
                        Label("", systemImage: "chevron.right")
                    }
                    .padding(.trailing, 48)
                }
            }
        }
    }
}

内容来源于stack exchange