Pro Android with Kotlin

4
CHAPTER 1: System
The help included in the studio and online resources provide enough information to master 
Android Studio. In this book, we will be talking about it once in a while and in dedicated 
chapters.
Virtual Devices
Developing software for computers always included the challenge to create one program 
that is able to handle all possible target systems. With handheld devices coming in so many 
different forms nowadays, this aspect has become more critical than ever before. You have 
smartphone devices with sizes between 3.9” and 5.4” and more, tablets from 7” to 14” and 
more, wearables, TVs at different sizes, and so on, all running with Android OS.
Of course, you as a developer cannot possibly buy all devices that are needed to cover all 
possible sizes. This is where emulators come in handy. With emulators you don’t have to buy 
hardware and you still can develop Android apps.
Android Studio
makes it easy for you to use emulators for developing and testing apps, and 
using the tools from the software development kit you can even operate the emulators from 
outside Android Studio.
Figure 1-2.
Android Studio
Caution
You 
can
develop apps without owning a single real device. This is, however, not 
recommended. You should have at least one smartphone from the previous generation and maybe 
also a tablet if you can afford it. The reason is that operating real devices feels different compared to 
emulators. The physical handling is not 100 percent the same, and the performance differs as well.

---

5
CHAPTER 1: System
To manage virtual devices from inside Android Studio, open the Android Virtual Device 
Manager via 
Tools 
➤
Android 
➤
 AVD Manager
. From here you can investigate, alter, create, 
delete, and start virtual devices. See Figure 
1-3
.
When creating a new virtual device, you will be able to choose from a TV, wear, phone, or 
tablet device; you can select the API level to use (and download new API levels); and in the 
settings you can specify things like this:
 
Graphics performance
 
Camera mode (advanced settings)
 
Network speed (advanced settings)
 
Boot option (advanced settings; quick boot considerably improves 
bootup speed once the device has been booted for the first time)
 
Number of simulated CPUs (advanced settings)
 
Memory and storage settings (advanced settings)
The virtual device base images and skins used for creating virtual images can be found here:
SDK_INST/system-images
SDK_INST/skins
The actual virtual devices with installed apps and user data are in the following location:
~/.android/avd