[AC][SampleApp] Clear cart state after onComplete (avoid failed onClick) (#333)

fix: cart left over from success won't work

Author: kieran-osgood-shopify

Samples/ShopifyAcceleratedCheckoutsApp/ShopifyAcceleratedCheckoutsApp/Views/CartBuilderView.swift

@@ -66,7 +66,8 @@ struct CartBuilderView: View {
 
                             ButtonSet(
                                 cart: $cart,
-                                firstVariantQuantity: cart.lines.nodes.first?.quantity ?? 1
+                                firstVariantQuantity: cart.lines.nodes.first?.quantity ?? 1,
+                                onComplete: clearCart
                             )
                         }
 
@@ -103,14 +104,7 @@ struct CartBuilderView: View {
                     isLoadingProducts: isLoadingProducts,
                     hasProducts: !allProducts.isEmpty,
                     onCreateCart: createCustomCart,
-                    onClearCart: {
-                        withAnimation {
-                            cart = nil
-                            selectedVariants.removeAll()
-                        }
-                        // Trigger scroll using state change
-                        scrollToTop = true
-                    }
+                    onClearCart: clearCart
                 )
                 .padding(.vertical, 12)
                 .background(Color(UIColor.systemBackground))
@@ -139,6 +133,15 @@ struct CartBuilderView: View {
         }
     }
 
+    private func clearCart() {
+        withAnimation {
+            cart = nil
+            selectedVariants.removeAll()
+        }
+        // Trigger scroll using state change
+        scrollToTop = true
+    }
+
     func onLoad() async {
         // Prevent multiple simultaneous loads
         guard !isLoadingProducts else {

Samples/ShopifyAcceleratedCheckoutsApp/ShopifyAcceleratedCheckoutsApp/Views/Components/ButtonSet.swift

@@ -28,6 +28,7 @@ import SwiftUI
 struct ButtonSet: View {
     @Binding var cart: Cart?
     let firstVariantQuantity: Int
+    let onComplete: () -> Void
 
     var body: some View {
         VStack(spacing: 16) {
@@ -37,6 +38,7 @@ struct ButtonSet: View {
                     AcceleratedCheckoutButtons(cartID: cartID)
                         .onComplete {
                             print("✅ Checkout completed successfully")
+                            onComplete()
                         }
                         .onFail {
                             print("❌ Checkout failed")