AndroidGestureRecognizer is an Android implementation of the Apple's UIGestureRecognizer framework. https://developer.apple.com/reference/uikit/uigesturerecognizer
For more info about the ui gesture recognizers look this WWDC video https://developer.apple.com/videos/play/wwdc2012/233/
UIGestureRecognizer is an abstract base class for concrete gesture-recognizer classes. A gesture-recognizer object—or, simply, a gesture recognizer—decouples the logic for recognizing a gesture and acting on that recognition. When one of these objects recognizes a common gesture or, in some cases, a change in the gesture, it sends an action message to each designated target object.
A simple, easy to use, no frills, form validator for Android.
A powerful image downloading and caching library for Android.