This tool is used to create and manage the virtual terminals (AVDs) that will host your emulator instances. These AVDs are used to simulate the software versions and hardware configurations available on different physical devices. This allows you to test your application on multiple hardware platforms without having to purchase the corresponding phones.
The Android SDK does not include any preconfigured virtual devices and you will need to create at least one before you can run your applications in an emulator.
Each device is configured by assigning it a name, a target version of Android (based on the SDK version it supports), an SD card capacity, and a screen resolution (see Figure 2.14).
You can also enable snapshot creation to save the state of the emulator when you exit it: launching an emulator from a snapshot is, indeed, much faster.
Each virtual device also supports many hardware settings and restrictions that can be added as name-value pairs in the hardware table. Selecting one of the predefined configurations will automatically use the appropriate values for these various settings.
These additional settings include:
the presence of a Dpad, touchscreen, keyboard or trackball;
support for accelerometer, GPS and proximity sensor;
the presence of the “back” and “home” keys.
Different hardware settings and screen resolutions will produce different screen layouts to represent different hardware configurations. This allows a wide variety of handsets to be simulated. Some manufacturers provide predefined settings for their products – Samsung, for example, makes them available as SDK packages.
The SDK Manager allows you to know which version of the SDK is installed and to install new ones when they become available.