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Android App Development (Kotlin) · Module 3 of 10

Activities, lifecycle and intents

Understand screens, their lifecycle and moving between them.

📖 Key ideas

  1. An Activity is an entry screen of an app.
  2. Lifecycle: onCreate, onStart, onResume, onPause, onStop, onDestroy.
  3. Configuration changes (rotation) recreate activities.
  4. Intents start activities or other apps (share, call, maps).
  5. Declare activities and permissions in AndroidManifest.xml.
💡 Real-life example: The lifecycle is a shop's daily routine: open, serve, pause for lunch, close.
ActivityA screen/entry point
onCreateLifecycle start method
IntentMessage to start a component
AndroidManifest.xmlApp declaration file