6. Android virtual device - Emulator

6.1. What is the Android Emulator?

The Android Development Tools (ADT) includes an emulator to run an Android system. The emulator behaves like a real Android device (in most cases) and allows you to test your application without having a real device.

You can configure the version of the Android system you would like to run, the size of the SD card, the screen resolution and other relevant settings. You can define several of them with different configurations.

These devices are called "Android Virtual Device" (AVD) and you can start several in parallel. Starting a new emulator is very slow, because the file system of the new AVD needs to get prepared.

The ADT allows to deploy and run your Android program on the AVD.

6.2. Google vs. Android AVD

During the creation of an AVD you decide if you want an Android device or a Google device.

An AVD created for Android will contain the programs from the Android Open Source Project. An AVD created for the Google API's will also contain several Google applications, most notable the Google Maps application.

If you want to use functionality which is only provided via the Google API's, e.g. Cloud2DeviceMessaging or Google Maps you must run this application on an AVD with Google API's.

6.3. Emulator Shortcuts

The following shortcuts are useful for working with the emulator.

Alt+Enter Maximizes the emulator. Nice for demos.

Ctrl+F11 changes the orientation of the emulator.

F8 Turns network on / off.

6.4. Performance

The graphics of the emulator are rendered in software, which is very slow. To have a responsive emulator use a small resolution for your emulator, as for example HVGA.

Also if you have sufficient memory on your computer, add at least 1 GB of memory to your emulator. This is the value "Device ram size" during the creation of the AVD.

Also set the flag "Enabled" for Snapshots. This will save the state of the emulator and will let it start much faster.

6.5. Hardware button

Android 4.0 introduced that devices do not have to have hardware button anymore. If you want to create such an AVD, add the "Hardware Back/Home keys" property to the device configuration and set it to "false".