notification-channel-compat adds Notification Channels support to pre-Oreo Android devices. You use the same required coding as for the Android 8.0 built-in channel classes, with minimal change, to add channel support for your app, to any Android 4.0+ device. In Android 8.0+ it uses the built-in channel classes, and in pre-Android 8.0, it mimics them. This frees developer of dealing with notification preferences for older devices, and easily allowed multiple preferences for multiple channels.
Color picker for v7 Preference Support Library.
Backport of Java 8 java.util.stream API to Java 6/7 and Android.
Smooth version of Google Support Design AppBarLayout.
Account Chooser for Android, backported from JellyBean.
Android library to backport Material design and allow changing colors at run-time.
Android-Device-Compatibility just yet another compatibility package for Android. This project aims to make the app compatible with various devices all over the world. The project will take care about lots of issues caused by device differences, so you don't need to write a weird compatibility code on your own.
Android CalendarView widget backported to 2.2 https://developer.android.com/reference/android/widget/CalendarView.html
A backport of the Switch widget (http://developer.android.com/reference/android/widget/Switch.html) that was introduced on Android 4. This port works on Android 2.1+.
Unofficial PreferenceFragment compatibility layer for Android 1.6 and up. Includes resources so add this as a library project to your project.
Android library for using the Honeycomb (Android 3.0) animation API on all versions of the platform back to 1.0!