Creating an app that pleases users is not an easy task. A cool idea is a great start but it is not enough. There are a large number of apps with high quality and users expectations are also high. After coding your idea, the next step is maximizing your app's performance. For example, users want apps that:

Use power sparingly.

Start up quickly.

Respond quickly to user interaction

Module 3 discusses how to create several UIs and how to interact with other apps. It also provides you with the know-how you need in order to make your apps not only cool but also performant. By now, you should have used Android Studio for a few weeks.

How did you find this tool? Do you prefer testing your app on a real device or the emulator? Did try to use the debugger, Lint, espresso?