In addition, you can also use the tools attributes for some error handling like tools:targetApi, and tools:ignore.

You can use the tools namespace in most (if not all) places you can use the Android namespace within your layouts. It makes design previews with real data really neat and easy - we don’t have to have hardcoded tool attribute values in our XML files. “ Sample data” as you might guess, helps us to provide sample data to populate our fields when working with layouts in Android studio. In this quick post, I’ll be sharing how you can take advantage of sample data resources in your project. I took the feature for a spin and decided to share my findings. However, with the new Android Studio 3.2 it’s even easier to use sample data in your projects. It has probably being around even longer. I first saw it in this year’s Google I/O Android app that was open sourced. Using sample data in Android Studio isn’t particularly a new feature. One of the nice features that caught my attention was the support for Sample data. The new release brings loads of goodies (explained in the release post here).

Recently, Android Studio 3.2 became stable.

Android studio preview window