Android SDK Notes By ShariqSP

Android SDK

The Android Software Development Kit (SDK) is a set of tools provided by Google to facilitate the development, testing, and deployment of Android applications. It includes a comprehensive collection of libraries, debuggers, emulators, and documentation necessary to create Android apps.

Key Components of Android SDK

  • SDK Tools: Essential tools for developing Android apps, such as the ADB (Android Debug Bridge) and Fastboot.
  • SDK Platform Tools: Tools that work directly with Android platforms and devices.
  • SDK Build Tools: Tools like Gradle, used to compile and build your application.
  • Emulator: A virtual Android device that allows testing apps on various versions of Android without requiring physical hardware.
  • Android Debug Bridge (ADB): A command-line tool for communication with an emulator instance or connected device.
  • API Libraries: Provide pre-built functions and classes to interact with the Android operating system and perform tasks such as networking, storage, and UI rendering.

Why Use the Android SDK?

The Android SDK simplifies application development by providing:

  • A unified development environment for writing code using languages like Java, Kotlin, and C++.
  • Tools to test, debug, and deploy applications on physical devices or emulators.
  • Access to APIs for system services, multimedia, location services, and more.
  • Backward compatibility for supporting different versions of the Android operating system.

Android Studio IDE

Android Studio is the official Integrated Development Environment (IDE) for Android app development, developed and maintained by Google. It provides a complete environment for building, testing, and debugging Android applications.

Features of Android Studio

  • Code Editor: A powerful editor with syntax highlighting, code suggestions, and refactoring tools.
  • Emulator: Built-in Android Emulator to test applications on various virtual devices.
  • Gradle Integration: Automates the build process with advanced dependency management.
  • Layout Editor: Drag-and-drop interface to design UI components visually.
  • Real-Time Previews: Allows developers to preview changes in UI designs instantly.
  • Performance Monitoring Tools: Tools to analyze CPU, memory, and network usage.

Getting Started with Android Studio

  1. Download the latest version of Android Studio.
  2. Install the software and set up the SDK during installation.
  3. Create a new project or import an existing one.
  4. Use the built-in emulator or connect a physical device for testing.

Android Studio supports multiple programming languages such as Java, Kotlin, and C++ and provides all the tools needed for full-stack Android app development.

Android Command Line Tools

The Android Command Line Tools provide a lightweight way to manage Android development processes without the Android Studio IDE. These tools are essential for automating builds, managing devices, and performing advanced debugging tasks.

Key Tools in Android Command Line Tools

  • ADB (Android Debug Bridge): A command-line tool to communicate with an emulator or a connected Android device. It supports file transfers, debugging, and shell commands.
  • SDK Manager: Allows installing, updating, and managing Android SDK components.
  • AVD Manager: Used to create and manage virtual devices (Android emulators).
  • Fastboot: A tool for flashing images, unlocking bootloaders, and recovering bricked devices.
  • Lint: Analyzes code to identify errors, inefficiencies, and potential bugs in the app.

Installing Android Command Line Tools

  1. Download the Command Line Tools package from the Android developer website.
  2. Extract the package and add the tools directory to your system's PATH variable.
  3. Run sdkmanager to install platform tools, build tools, and desired SDK versions.

Basic Commands

  • adb devices: Lists connected devices.
  • adb install app.apk: Installs an APK to a connected device.
  • sdkmanager --list: Lists available SDK components.
  • avdmanager create avd: Creates a virtual device.

The command-line tools are ideal for advanced users, CI/CD pipelines, or developers who prefer a lightweight and scriptable development setup.

Setting Environment Variables for Android SDK

To ensure the Android SDK tools and commands work seamlessly from the terminal or command prompt, you need to configure the environment variables on your system. This step makes tools like adb, sdkmanager, emulator, and build tools globally accessible.

Steps to Set Environment Variables

1. Locate Your Android SDK Path

Find the path where the Android SDK is installed. The default installation directories are:

  • Windows: C:\Users\YourUsername\AppData\Local\Android\Sdk
  • macOS/Linux: /Users/YourUsername/Library/Android/sdk or /home/YourUsername/Android/Sdk

2. Set Environment Variables

Depending on your operating system, follow these steps:

On Windows
  1. Right-click on "This PC" or "Computer" and select Properties.
  2. Go to Advanced System Settings > Environment Variables.
  3. Under System Variables, click New and set:
    • Variable Name: ANDROID_HOME
    • Variable Value: Path to your Android SDK (e.g., C:\Users\YourUsername\AppData\Local\Android\Sdk).
  4. Edit the Path variable and add the following:
    • %ANDROID_HOME%\tools
    • %ANDROID_HOME%\tools\bin
    • %ANDROID_HOME%\platform-tools
    • %ANDROID_HOME%\build-tools\{version} (Replace {version} with the installed build-tools version, e.g., 34.0.0).
  5. Click OK to save and restart your system.
On macOS/Linux
  1. Open the terminal and edit your shell configuration file:
    • ~/.bashrc or ~/.bash_profile (for Bash)
    • ~/.zshrc (for Zsh)
  2. Add the following lines at the end of the file: 
    export ANDROID_HOME=$HOME/Android/Sdk
                export PATH=$PATH:$ANDROID_HOME/tools
                export PATH=$PATH:$ANDROID_HOME/tools/bin
                export PATH=$PATH:$ANDROID_HOME/platform-tools
                export PATH=$PATH:$ANDROID_HOME/build-tools/{version}

    Replace {version} with the version of build tools installed, such as 34.0.0.

  3. Save the file and run the following command to apply the changes: 
    source ~/.bashrc
    or 
    source ~/.zshrc

3. Verify the Configuration

To ensure the environment variables are set correctly, open a terminal or command prompt and run:

adb --version

If the configuration is correct, it will display the version of the Android Debug Bridge tool.

To verify the Build Tools path, run:

aapt version

This will confirm that the Android Asset Packaging Tool (aapt) is accessible.

Summary

Setting environment variables for the Android SDK ensures tools like adb, sdkmanager, and aapt (Build Tools) are accessible globally. This is essential for smooth Android development and build processes.

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