Virtual devices

There are so many Android devices available on the market that it would be an impossibility to thoroughly test our apps on very many real devices . It is for this reason that the system allows us to create emulated devices using the virtual device manager.

The AVD Manager allows us to create both form factor and hardware profiles from scratch and to provide several ready-made virtual devices and system images that can be downloaded from various manufacturers' websites.

Android emulators can be notoriously slow, even on very powerful machines, and this is to be expected, as creating a fully functioning virtual device is a remarkably complex task. There are, however, a few things that can be done to speed things up a little by designing each virtual device to match the particular tasks of the app we are developing. For example, if your app does not make use of the device camera, then do not include it in the configuration. Likewise, do not allocate much more memory than the app itself requires.

Android virtual devices are not the only option available to us, and there are a small but growing number of third-party emulators. Many of these are designed with gamers rather than developers in mind; although Genymotion is specifically a development tool, it contains more functions and is generally faster than the native emulators. Its only drawbacks are that is only free for personal use and only provides system images for phones and tablets and not wearables or large screen devices, such as TVs.

Real-world devices naturally respond far faster than any emulator and, when it comes to testing basic functionality, using our own devices will provide swifter results. This approach is great for testing the fundamentals of an app but provide little to no feedback on just how our apps will look on the wide variety of screen sizes, shapes, and densities that Android devices can have.

Using real devices is a fast way to test application logic but developing apps for specific models or even generic size and shapes will inevitably require the creation of virtual devices. Fortunately, Android Studio comes equipped with an accelerated build process: Instant Run.