Android app development is the practice of building lifecycle-driven software that runs on the Android platform, typically using Kotlin with the Android SDK + AndroidX (Jetpack). Most production complexity comes from coordinating UI state with asynchronous work (network, storage, background execution) while respecting component lifecycles and modern platform restrictions. A useful mental model is: the system owns your process and components, and your app reacts to callbacks, intents, and state rather than “owning” a linear main loop.