SwiftUI实现点击分段Picker选项后先弹出确认弹窗，确认后再切换选项

Got it, let's fix this up! The problem with your current code is that the Picker’s selection is directly bound to favoriteColor—so when you tap a segment, the selection switches immediately, and then the alert pops up. That’s backwards from what you want. Here’s a clean way to implement the "confirm first" behavior:

struct ContentView: View {
    @State private var favoriteColor = 0
    @State private var pendingColorSelection: Int?
    @State private var showAlert = false
    
    var body: some View {
        VStack {
            // Use a custom Binding to control when the selection updates
            Picker("What is your favorite color?", selection: Binding(
                get: { favoriteColor },
                set: { newValue in
                    // Save the tapped value temporarily, then show the alert
                    pendingColorSelection = newValue
                    showAlert = true
                }
            )) {
                Text("Red").tag(0)
                Text("Green").tag(1)
            }
            .pickerStyle(.segmented)
            .alert("By changing color also modifies other things...change color?", isPresented: $showAlert) {
                Button("YES") {
                    // Update the actual selection only if user confirms
                    if let newColor = pendingColorSelection {
                        favoriteColor = newColor
                    }
                }
                Button("Cancel", role: .cancel) {
                    // Clear the pending value—Picker will revert to the original selection automatically
                    pendingColorSelection = nil
                }
            }
        }
    }
}

How this works: #

• Custom Binding: Instead of directly binding to $favoriteColor, we create a custom binding. The get closure ensures the Picker always displays the current confirmed selection. The set closure triggers when the user taps a new segment—instead of updating the actual selection right away, it saves the new value to pendingColorSelection and shows the alert.
• Confirmation Logic:
  • If the user taps "YES", we take the pending value and update favoriteColor, which makes the Picker switch to the new segment.
  • If the user taps "Cancel", we just clear the pending value. Since the Picker’s binding still reads from favoriteColor, it stays on the original selection—no extra work needed to revert it.
• Cancel Role: Adding role: .cancel to the Cancel button gives it system-standard behavior (like being the default dismiss option, and proper styling on different platforms).

内容的提问来源于stack exchange，提问作者fs_tigre