Ripple effect on touched item

Google has started to use ripple animations in Material Design UIs. The setHotspot() method is added in API Level 21. This teaches the drawable a “hot spot”, and the RippleDrawable apparently uses this as the emanation point for the ripple effect. The setHotspot() method of a view take the x,y values from the MotionEvent to set the hot spot coordinates.

Source: http://commonsware.com/

Android Reflection-API Constructor without parameters

If you have to create an object with default constructor, you can invoke the newInstance() method on a Class.
This simple class creates the instance of a named class using the empty default constructor by calling the newInstance method:

Read bitmap from asset

Source: http://github.com/

Hide Keyboard

Request to hide the soft input window from the context of the window that is currently accepting input. This should be called as a result of the user doing some actually than fairly explicitly requests to have the input window hidden.

Source: https://www.reddit.com/r/androiddev/wiki/utilities