Building and Running from Eclipse with ADT

Eclipse and ADT provide an environment where most of the details of the build process are hidden from you. By default, the build process constantly runs in the background as you make changes to your project.

When Eclipse automatically builds your application, it enables debugging and signs the .apk with a debug key, by default. When you run the application, Eclipse invokes ADB and installs your application to a device or emulator, so you do not have to manually perform these tasks. Since most of the build process is taken care of by Eclipse, the following topics show you how to run an application, which will automatically build your application as well.

To distribute your application, however, you must build your application in release mode and sign the .apk file with your own private key.

This document shows you how to run your application on an emulator or a real device from Eclipse—all of which is done using the debug version of your application. For more information about how to sign your application with a private key for release, see Signing Your Applications

Running on the emulator

Before you can run your application on the Android Emulator, you must create an AVD.

To run (or debug) your application, select Run > Run (or Run > Debug) from the Eclipse menu bar. The ADT plugin will automatically create a default run configuration for the project. Eclipse will then perform the following:

  1. Compile the project (if there have been changes since the last build).
  2. Create a default run configuration (if one does not already exist for the project).
  3. Install and start the application on an emulator (or device), based on the Deployment Target defined by the run configuration.

    By default, Android run configurations use an "automatic target" mode for selecting a device target. For information on how automatic target mode selects a deployment target, see Automatic and manual target modes below.

If you run the application with the Debug option, the application will start in the "Waiting For Debugger" mode. Once the debugger is attached, Eclipse opens the Debug perspective and starts the application's main activity. Otherwise, if you run the application with the normal Run option, Eclipse installs the application on the device and launches the main activity.

To set or change the run configuration used for your project, use the run configuration manager. See the section below about Creating a Run Configuration for more information.

Be certain to create multiple AVDs upon which to test your application. You should have one AVD for each platform and screen type with which your application is compatible. For instance, if your application compiles against the Android 4.0 (API Level 14) platform, you should create an AVD for each platform equal to and greater than 4.0 and an AVD for each screen type you support, then test your application on each one.

Running on a device

Before you can run your application on a device, you must perform some basic setup for your device:

  • Ensure that your application is debuggable by setting the android:debuggable attribute of the <application> element to true. As of ADT 8.0, this is done by default when you build in debug mode.
  • Enable USB debugging on your device.


  • Ensure that your development computer can detect your device when connected via USB

Read Using Hardware Devices for more information.


Creating a Run Configuration

The run configuration specifies the project to run, the Activity to start, the emulator or connected device to use, and so on. When you first run a project as an Android Application, ADT will automatically create a run configuration. The default run configuration will launch the default project Activity and use automatic target mode for device selection (with no preferred AVD). If the default settings don't suit your project, you can customize the run configuration or even create a new one.

To create or modify a run configuration, refer to the Eclipse documentation on how to create Run configurations. The following steps highlight the important things you need to do for an Android project:

  1. Open the run configuration manager from the Run Menu.
  2. Expand the Android Application item and create a new configuration or open an existing one.
  3. With the Run Configuration selected, adjust your desired run configuration settings:
    • In the Android tab, specify the Project and Activity to launch.
    • In the Target tab, consider whether you'd like to use Manual or Automatic mode when selecting an AVD to run your application. See the following section on Automatic and manual target modes).

      You can specify any emulator options to the Additional Emulator Command Line Options field. For example, you could add -scale 96dpi to scale the AVD's screen to an accurate size, based on the dpi of your computer monitor. For a full list of emulator options, see the Android Emulator document.

Automatic and manual target modes

By default, a run configuration uses the automatic target mode in order to select an AVD. In this mode, ADT will select an AVD for the application in the following manner:

  1. If there's a device or emulator already running and its AVD configuration meets the requirements of the application's build target, the application is installed and run upon it.
  2. If there's more than one device or emulator running, each of which meets the requirements of the build target, a "device chooser" is shown to let you select which device to use.
  3. If there are no devices or emulators running that meet the requirements of the build target, ADT looks at the available AVDs. If there is an AVD that matches the build target of the project, ADT chooses that AVD. If the AVD versions are newer than the build target of the project, ADT chooses the oldest possible version of an AVD that meets the project's build target requirement.
  4. If there are no suitable AVDs, the application is not installed a console error warning tells you that there is no existing AVD that meets the build target requirements.

However, if a "preferred AVD" is selected in the run configuration, then the application will always be deployed to that AVD. If it's not already running, then a new emulator will be launched.

If your run configuration uses manual mode, then the "device chooser" is presented every time that your application is run, so that you can select which AVD to use.