SwiftUI中如何持久化保存按钮的选中状态与颜色？

直接把父视图里的@State替换成@AppStorage就能实现状态持久化，不需要手动操作UserDefaults，具体修改如下：

修改后的完整代码 #

struct HeartButtonView: View {
    // 用@AppStorage替换@State，指定存储key，自动持久化到UserDefaults
    @AppStorage("isHeartLiked") private var isLiked = false
    var body: some View {
        HeartButton(isLiked: $isLiked)
    }
}

struct HeartButton: View {
    @Binding var isLiked: Bool
    @State private var animate = false
    private let animationDuration: Double = 0.1
    private var animationScale: CGFloat {
        isLiked ? 0.7 : 1.3
    }
    
    var body: some View {
        Button {
            self.animate = true
            DispatchQueue.main.asyncAfter(deadline: .now() + self.animationDuration) {
                self.animate = false
                self.isLiked.toggle()
            }
        } label: {
            Image(systemName: isLiked ? "heart.fill" : "heart")
                .resizable()
                .aspectRatio(contentMode: .fit)
                .frame(width: 50)
                .foregroundColor(isLiked ? .red : .gray)
        }
        .scaleEffect(animate ? animationScale : 1)
        .animation(.easeIn(duration: animationDuration), value: animate)
    }
}

关键说明 #

• @AppStorage("isHeartLiked")：这个属性包装器会自动把isLiked的值存在UserDefaults里，key设为isHeartLiked确保唯一，重启应用时会自动读取该key对应的初始值
• 子视图的@Binding无需改动，依然负责接收父视图的状态绑定、处理点击动画逻辑
• 点击按钮触发isLiked.toggle()时，状态会自动同步到UserDefaults，无需额外编写存储代码

内容的提问来源于stack exchange，提问作者Denis