Introduction to Android Development

Overview of Android OS

History and Versions of Android

• Android is a mobile operating system developed by Google, based on a modified version of the Linux kernel and other open-source software. Initially developed by Android Inc., which Google bought in 2005, Android was unveiled in 2007, with the first commercial Android device launched in September 2008.
• Android versions are named after sweets or desserts. Notable versions include:
  • Android 1.5 (Cupcake): Introduced on-screen keyboards.
  • Android 2.2 (Froyo): Added support for Flash.
  • Android 4.0 (Ice Cream Sandwich): Introduced a unified UI for tablets and phones.
  • Android 5.0 (Lollipop): Brought Material Design and 64-bit support.
  • Android 8.0 (Oreo): Introduced Project Treble for modularity and faster updates.
  • Android 12: Focused on UI personalization with Material You design language.
  • Android 14 (Upside Down Cake): The latest version, with enhancements in privacy, security, and multitasking.

Android Architecture and Components

• Linux Kernel: The core of Android, responsible for device drivers, power management, and system services.
• Hardware Abstraction Layer (HAL): Interfaces between the Android framework and the hardware drivers.
• Android Runtime (ART): Runs apps and manages memory. Since Android 5.0, ART replaced Dalvik as the runtime environment.
• Application Framework: Provides high-level services like Activity Manager, Resource Manager, and Notification Manager.
• Applications: The top layer where apps like contacts, browser, and games run.

Setting Up the Development Environment

Installing Android Studio

• Download and Install: Android Studio is the official IDE for Android development, available for download from the official Android developer website. Installation includes Android SDK, Android Emulator, and a set of tools for debugging and testing your apps.

Introduction to Android SDK and AVD

• Android SDK (Software Development Kit): A set of tools that includes libraries, documentation, and sample code to develop Android apps.
• AVD (Android Virtual Device): An emulator configuration that allows you to run and test your Android apps on a simulated device. AVD Manager in Android Studio allows you to create and manage these devices.

First Android Project

Creating a New Project

• Steps:
  1. Open Android Studio and select “Start a new Android Studio project”.
  2. Choose a template (e.g., Empty Activity).
  3. Configure the project with a name, package name, and save location.
  4. Select the language (Java/Kotlin) and the minimum SDK version.
  5. Finish the setup to generate the project files.

Understanding Project Structure

• Project Structure:
  • Manifest: AndroidManifest.xml file that contains essential information about the app, such as the package name, activities, permissions, etc.
  • Java/Kotlin: Contains source code files for your app, including activities, fragments, and services.
  • Res (Resources): Directory for app resources like layouts (XML files), drawable (images), strings, and styles.
  • Gradle Scripts: Build files (build.gradle) that manage dependencies, build types, and other configurations.