Android is an open-source mobile operating system based on the Linux kernel.

The lifecycle includes stages like onCreate(), onStart(), onResume(), onPause(), onStop(), and onDestroy().

Four layers: Linux Kernel, Libraries, Android Runtime, Application Framework, and Applications.

RecyclerView efficiently displays large data sets as a scrollable list or grid.

APK (Android Package) is the package file format used to distribute Android apps.

A Handler allows executing code and updating UI from a background thread.

ViewModel stores and manages UI-related data in a lifecycle-conscious way.

Jetpack is a suite of libraries to help developers follow best practices and reduce boilerplate.

Room provides an abstraction layer over SQLite to enable fluent database access.

A View is the basic building block for UI components like buttons and text fields.

ContentProvider manages access to a structured set of app data, usually stored in databases.

Gradle is the build automation system used to compile, package, and manage dependencies.

Services run background tasks without a user interface, like playing music or downloading files.

A Toast is a short message displayed on the screen without user interaction.

ANR (Application Not Responding) occurs when the main thread is blocked for too long.

LiveData is an observable data holder class that updates the UI when data changes.

Explicit targets specific components; implicit lets the system find the appropriate component.

Context provides access to application-specific resources and classes.

BroadcastReceiver handles communication between the system and applications through broadcast messages.

Java and Kotlin are the primary programming languages for Android app development.

An Activity represents a single screen with a user interface in an Android app.

It declares app components, permissions, and configuration settings for the Android app.

A Fragment is a reusable portion of the user interface inside an Activity.

Originally developed by Android Inc., later acquired by Google in 2005.

An Intent is a messaging object used to request an action from another app component.