The Live Preview Canvas
Use Xcode previews to see UI changes instantly.
The Live Preview Canvas is a free SwiftUI Academy lesson on CoddyKit — lesson 3 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the SwiftUI Academy learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
Meet the Canvas
Beside your code, Xcode shows a canvas that renders your view live. You see your UI without ever building and launching the full app. 👀
Show or Hide It
If the canvas is missing, open the Editor menu and turn on Canvas. It appears on the right, next to your Swift code.
The #Preview Block
A small #Preview block at the bottom of the file tells the canvas what to render. The template adds one for ContentView automatically.
#Preview {
ContentView()
}Live Updates
Change your code and the canvas refreshes almost instantly. This live update loop is what makes SwiftUI feel fast and playful. ⚡
Try an Edit
Edit the Text view's wording and watch the canvas change as you type. Seeing results immediately makes experimenting safe and fun.
Text("Hello, SwiftUI!")Resume the Preview
Sometimes the canvas pauses and shows a Resume button. Click it to restart the preview after a change it could not apply live.
Interactive Mode
The play-style live mode lets you tap and scroll right in the canvas. You can test buttons and gestures without a simulator.
Preview Devices
You can point a preview at a specific device, like an iPhone SE. This helps you check how your layout looks on smaller screens.
Multiple Previews
Add more than one #Preview block to compare states side by side, such as light mode next to dark mode at the same time.
Previews Are Not Shipped
Preview code is for development only. It never ships to users, so feel free to fill previews with fake sample data.
Faster Than Building
The canvas is far quicker than a full build. Use it as your main loop while designing, and reach for the simulator only for deeper testing.
Quick Check
Which block in your file tells the canvas what to render?
Recap
The canvas renders your view live via a #Preview block, updating as you type. It is your fastest way to design and iterate. 🎨
Frequently asked questions
Is the “The Live Preview Canvas” lesson free?
Yes — the full text of “The Live Preview Canvas” is free to read here on the web, and the SwiftUI Academy course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the SwiftUI Academy course, upgrade to CoddyKit PRO.
What will I learn in “The Live Preview Canvas”?
Use Xcode previews to see UI changes instantly. You practise SwiftUI Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start SwiftUI Academy?
No prior experience is required. SwiftUI Academy on CoddyKit is structured for beginners through advanced learners; this is — lesson 3 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “The Live Preview Canvas” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this SwiftUI Academy lesson?
Yes. Every SwiftUI Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.