Popular Opensources used in Android

• AutoFitTextView: A TextView that automatically resizes text to fit perfectly within its bounds ( github )
• android-linear-layout-manager: 
• Barber: https://github.com/hzsweers/barber
• Butterknife: https://github.com/JakeWharton/butterknife
• GoldenGate: https://github.com/Flipboard/GoldenGate
• Material Dialogs: https://github.com/afollestad/material-dialogs
• MaterialEditText: https://github.com/rengwuxian/MaterialEditText
• OkHttp: An HTTP & HTTP/2 client for Android and Java applications. https://github.com/square/okhttp
• Otto: An enhanced Guava-based event bus with emphasis on Android support https://github.com/square/otto
• RxJava: Reactive Extensions for the JVM – a library for composing asynchronous and event-based programs using observable sequences for the Java VM. https://github.com/ReactiveX/RxJava
• RxAndroid: Reactive Extensions for Android https://github.com/ReactiveX/RxAndroid
• StickyListHeaders: an Android library that makes it easy to integrate section headers in your ListView https://github.com/emilsjolander/StickyListHeaders
• VerticalViewPager: https://github.com/castorflex/VerticalViewPager
• zxing: an open-source, multi-format 1D/2D barcode image processing library implemented in Java, with ports to other languages.
• DynamicGrid: Drag and drop GridView for Android.
• HockeySDK: Distribute beta versions, collect live crash reports, get feedback from real users and analyze test coverage.
• TextDrawable: provides images with letter/text
• TokenAutoComplete: Gmail style MultiAutoCompleteTextView for Android
• Rebound: a java library that models spring dynamics. Rebound spring models can be used to create animations that feel natural by introducing real world physics to your application.
• Android-betterpickers: Android library for better Picker DialogFragments https://github.com/code-troopers/android-betterpickers
• android-gif-drawable: Views and Drawable for displaying animated GIFs on Android https://github.com/koral--/android-gif-drawable
• Dagger: A fast dependency injector for Android and Java. https://github.com/square/dagger
• LoganSquare: Screaming fast JSON parsing and serialization library for Android. https://github.com/bluelinelabs/LoganSquare
• ANTLR:
• android-async-http: An asynchronous, callback-based Http client for Android built on top of Apache's HttpClient libraries.
• chat sdk - https://github.com/AppLozic/Applozic-Android-SDK