Underneath: How Apps Are Made

You use apps every day. What happens underneath the screen? Why does a tap change a number? How can a few lines of code create a whole list? What is that loading spinner waiting for? Underneath helps you understand by changing a small example app and watching it respond. No programming experience required. Start with Sprout, a plant-watering example app. Change its words, adjust numbers and colors, and rearrange its layout. The preview responds as you experiment. Tap something on the screen to find its code, or select a line of code to see what it controls. 10 hands-on lessons • See how code describes words, appearance, and layout. • Discover how taps change state, data fills lists, and conditions decide what appears. • Explore connected screens and a simulated network, including loading and failure. • Remix the example with code pieces you have learned. • Follow a teaching simulation of building, installing, and releasing an app. Try first. Understand what happened. Short explanations follow each guided experiment. Plain-language notes connect the code to what you see. Explore intentional errors and watch what changes when you fix them. Keep the ideas that click. Collect a concept card after each lesson and build a map of how apps work. Completed lessons and your saved remix stay on your device for later review. For curious people Designers, product managers, students, and first-time learners can explore the ideas behind the apps they use every day. Available in English and Simplified Chinese. Network requests, builds, installation, and App Store release steps are teaching simulations. Try lessons 1–3 for free. Unlock lessons 4–10 with a one-time in-app purchase. No subscription. The purchase price is shown in the app, and Restore purchase is available on the unlock screen. Terms of Use： https://www.apple.com/legal/internet-services/itunes/dev/stdeula/