MaterialDesignLibrary

MaterialDesignLibrary is an Android library written in Java that brings Google's Material Design visual style to older Android apps. Material Design is the visual language Google introduced with Android 5.0 (Lollipop) in 2014, featuring flat colors, animated buttons, and clean typography. This library lets developers use those same design components in apps that target Android 2.2 and above, so they could support users on much older devices while still looking modern.

The library provides a set of ready-made UI components that you add to your app's layout files using XML, the same way you would add standard Android interface elements. The components included are flat buttons, rectangle buttons, floating action buttons (the circular buttons that hover in a corner), checkboxes, toggle switches, several styles of progress bars, sliders, snackbars (the small pop-up notification strips that appear at the bottom of the screen), dialogs, and a color picker.

Each component is dropped into a layout file with a few lines of XML referencing the library's custom view classes. Some components have extra customization options exposed through custom XML attributes, such as setting the minimum and maximum values on a slider or disabling the entry animation on a floating button.

Installing it uses Gradle, the standard Android build tool. You add a one-line dependency to your project's build file and it is included automatically.

This project appears to have been created around 2014 to 2015, when Material Design was new and before Google shipped its own official Material Design support library. It is primarily of historical interest now, as Google's own libraries have since made this kind of backport unnecessary.