Get the Android SDK

The Android SDK provides you the API libraries and developer tools necessary to build, test, and debug apps for Android.

If you're a new Android developer, we recommend you download the ADT Bundle to quickly start developing apps. It includes the essential Android SDK components and a version of the Eclipse IDE with built-in ADT (Android Developer Tools) to streamline your Android app development.

With a single download, the ADT Bundle includes everything you need to begin developing apps:

• Eclipse + ADT plugin
• Android SDK Tools
• Android Platform-tools
• The latest Android platform
• The latest Android system image for the emulator

Download the ADT Plugin

1. Start Eclipse, then select Help > Install New Software.
2. Click Add, in the top-right corner.
3. In the Add Repository dialog that appears, enter "ADT Plugin" for the Name and the following URL for the Location:

   https://dl-ssl.google.com/android/eclipse/

4. Click OK.
   

   If you have trouble acquiring the plugin, try using "http" in the Location URL, instead of "https" (https is preferred for security reasons).

5. In the Available Software dialog, select the checkbox next to Developer Tools and click Next.
6. In the next window, you'll see a list of the tools to be downloaded. Click Next.
7. Read and accept the license agreements, then click Finish.
   

   If you get a security warning saying that the authenticity or validity of the software can't be established, click OK.

8. When the installation completes, restart Eclipse

SDK Manager

The Android SDK separates tools, platforms, and other components into packages you can download using the SDK Manager.

You can launch the SDK Manager in one of the following ways:

• From Eclipse (with ADT), select Window > Android SDK Manager.
• On Windows, double-click the SDK Manager.exe file at the root of the Android SDK directory.
• On Mac or Linux, open a terminal and navigate to the tools/ directory in the Android SDK, then execute android sdk.

You can select which packages you want to download by toggling the checkboxes on the left, then click Install to install the selected packages.

Create a Project with Eclipse

1. Click New in the toolbar.
2. In the window that appears, open the Android folder, select Android Application Project, and click Next.


Figure 1. The New Android App Project wizard in Eclipse.

3. Fill in the form that appears:
   
   • Application Name is the app name that appears to users. For this project, use "My First App."
   • Project Name is the name of your project directory and the name visible in Eclipse.
   • Package Name is the package namespace for your app (following the same rules as packages in the Java programming language). Your package name must be unique across all packages installed on the Android system. For this reason, it's generally best if you use a name that begins with the reverse domain name of your organization or publisher entity. For this project, you can use something like "com.example.myfirstapp." However, you cannot publish your app on Google Play using the "com.example" namespace.
   • Minimum Required SDK is the lowest version of Android that your app supports, indicated using the API level. To support as many devices as possible, you should set this to the lowest version available that allows your app to provide its core feature set. If any feature of your app is possible only on newer versions of Android and it's not critical to the app's core feature set, you can enable the feature only when running on the versions that support it (as discussed in Supporting Different Platform Versions). Leave this set to the default value for this project.
   • Target SDK indicates the highest version of Android (also using the API level) with which you have tested with your application.
     

     As new versions of Android become available, you should test your app on the new version and update this value to match the latest API level in order to take advantage of new platform features.

   • Compile With is the platform version against which you will compile your app. By default, this is set to the latest version of Android available in your SDK. (It should be Android 4.1 or greater; if you don't have such a version available, you must install one using the SDK Manager). You can still build your app to support older versions, but setting the build target to the latest version allows you to enable new features and optimize your app for a great user experience on the latest devices.
   • Theme specifies the Android UI style to apply for your app. You can leave this alone.

   Click Next.

4. On the next screen to configure the project, leave the default selections and click Next.
5. The next screen can help you create a launcher icon for your app.
   

   You can customize an icon in several ways and the tool generates an icon for all screen densities. Before you publish your app, you should be sure your icon meets the specifications defined in the Iconography design guide.

   Click Next.

6. Now you can select an activity template from which to begin building your app.
   

   For this project, select BlankActivity and click Next.

7. Leave all the details for the activity in their default state and click Finish.

Run on a Real Device

If you have a real Android-powered device, here's how you can install and run your app:

1. Plug in your device to your development machine with a USB cable. If you're developing on Windows, you might need to install the appropriate USB driver for your device. For help installing drivers, see the OEM USB Drivers document.
2. Enable USB debugging on your device.
   
   • On most devices running Android 3.2 or older, you can find the option under Settings > Applications > Development.
   • On Android 4.0 and newer, it's in Settings > Developer options.
     

     Note: On Android 4.2 and newer, Developer options is hidden by default. To make it available, go to Settings > About phone and tap Build number seven times. Return to the previous screen to find Developer options.
     

Run on the Emulator

Whether you're using Eclipse or the command line, to run your app on the emulator you need to first create an Android Virtual Device (AVD). An AVD is a device configuration for the Android emulator that allows you to model different devices.

Figure 1. The AVD Manager showing a few virtual devices.

To create an AVD:

1. Launch the Android Virtual Device Manager:
   
   1. In Eclipse, click Android Virtual Device Manager from the toolbar.
   2. From the command line, change directories to <sdk>/tools/ and execute:

      android avd

2. In the Android Virtual Device Manager panel, click New.
3. Fill in the details for the AVD. Give it a name, a platform target, an SD card size, and a skin (HVGA is default).
4. Click Create AVD.
5. Select the new AVD from the Android Virtual Device Manager and click Start.
6. After the emulator boots up, unlock the emulator screen.

This lesson teaches you to

1. Create a Linear Layout
2. Add a Text Field
3. Add String Resources
4. Add a Button
5. Make the Input Box Fill in the Screen Width

This lesson teaches you to

1. Respond to the Send Button
2. Build an Intent
3. Start the Second Activity
4. Create the Second Activity
5. Receive the Intent
6. Display the Message

Welcome to code samples for Android developers. Here you can browse sample code and learn how to build different components for your applications. Use the categories on the left to browse the available samples.

Each sample is a fully functioning Android app. You can browse the resources, source files and see the overall project structure. You can copy and paste the code you need, and if you want to share a link to a specific line you can double-click it to the get the url.

If you want to download a complete project, just click on any source file in the project and click the link in the upper right of the source page.