🛒 Adding a Count Badge to the Cart Tab in .NET MAUI Shell Tab Bar

In this blog post, we will explore how to add a dynamic count badge 🔢 on the cart tab in the Shell Tab Bar in a .NET MAUI application. This will ensure that users can see the number of items in their cart at a glance, improving usability and engagement. 🚀

🎯 Why Add a Badge?

A count badge on a cart tab enhances the user experience by visually indicating the number of items in the cart. 🛍️ This is a common UX pattern in e-commerce and shopping applications, making it easy for users to track their selections.

🛠️ Implementation Overview

We will customize the Shell Tab Bar by creating a custom ShellRenderer and ShellTabBarAppearanceTracker in .NET MAUI for iOS. The badge count will be dynamically updated based on the cart items. 🛒📊

📌 Steps to Implement

1️⃣ Add a TabBar in AppShell

To include a cart tab in the Shell Tab Bar, update your AppShell.xaml to define the ShellContent for the cart:

<TabBar>
    <ShellContent Title="Home" Icon="home.png" Route="home" ContentTemplate="{DataTemplate local:HomePage}" />
    <ShellContent Title="Cart" Icon="cart.png" Route="cart" ContentTemplate="{DataTemplate local:CartPage}" />
    <ShellContent Title="Profile" Icon="profile.png" Route="profile" ContentTemplate="{DataTemplate local:ProfilePage}" />
</TabBar>

2️⃣ Create a Custom Shell Renderer

We need to extend ShellRenderer to apply our custom tab bar appearance tracker.

using Microsoft.Maui.Controls.Platform.Compatibility;
using CartBadge.Platforms.iOS.Customization.ShellTab;

[assembly: ExportRenderer(typeof(AppShell), typeof(CustomShellRenderer))]
namespace CartBadge.Platforms.iOS.Customization.ShellTab
{
    public class CustomShellRenderer : ShellRenderer
    {
        protected override IShellTabBarAppearanceTracker CreateTabBarAppearanceTracker()
        {
            return new CustomTabBarAppearanceTracker();
        }
    }
}

3️⃣ Create a Custom Tab Bar Appearance Tracker

The CustomTabBarAppearanceTracker class will handle the badge update dynamically. 🔄

using Foundation;
using UIKit;
using Microsoft.Maui.Controls.Platform.Compatibility;
using Microsoft.Maui.Dispatching;

namespace CartBadge.Platforms.iOS.Customization.ShellTab
{
    public class CustomTabBarAppearanceTracker : ShellTabBarAppearanceTracker
    {
        private static UITabBarController _tabBarController;

        public override void SetAppearance(UITabBarController controller, ShellAppearance appearance)
        {
            base.SetAppearance(controller, appearance);
            _tabBarController = controller;
        }

        public static void RefreshCartBadge(int count)
        {
            MainThread.BeginInvokeOnMainThread(() =>
            {
                if (_tabBarController?.TabBar?.Items == null) return;

                foreach (var item in _tabBarController.TabBar.Items)
                {
                    if (item.Title == "Cart")
                    {
                        item.BadgeValue = count > 0 ? count.ToString() : null;
                    }
                }
            });
        }

        protected override void Dispose(bool disposing)
        {
            if (disposing)
            {
                _tabBarController = null;
            }
            base.Dispose(disposing);
        }
    }
}

4️⃣ Update Badge Dynamically

To update the badge count dynamically, call RefreshCartBadge(int count) whenever the cart updates. 📈

CustomTabBarAppearanceTracker.RefreshCartBadge(cartItemCount);

🎉 Conclusion

By implementing a custom ShellRenderer and ShellTabBarAppearanceTracker, we can efficiently add a cart badge count in the Shell Tab Bar for .NET MAUI iOS applications. This enhances usability and improves user engagement with the cart functionality. 💡📱

🚀 Android implementation is in progress and will be uploaded soon! Stay tuned for updates. 📢📲

Do you have any questions or want further improvements? Let me know in the comments! 💬