NGUI is a powerful UI system and event notification framework for Unity (both Pro and Free) written in C# that closely follows the . It features clean code and simple, minimalistic approach to everything. Most classes are kept under 200 lines of code. For a programmer this means a much easier time when it comes to working with the kit — from extending its functionality to tweaking the existing one. For everyone else this means better performance, less frustration, and more fun.
If you want to go in depth of NGUI then follow the bellow link..
1. For Background Image or Screen Resolution Problem on Android while using NGUI with Unity
for background image…Use UIStretch…!
Go To Component -> NGUI ->UI->UIStretch..!
adjust Style to Both in UIStretch script.
2. For Button View Problem in NGUI on Android Devices–
If your button position is not same for all existing android devices then do the following step to get it right.
NGUI…->Attach An Anchor to Buttons Group, Game Object…!
Then in UIAnchor Script set the side property. For Example for The given View/Screen ……
Group High Score,Option,Share buttons to a group…Anchor it to BottomLeft using side property.
Group Play,Help buttons to a group…Anchor it to Bottom using side property.
Group MoreFunGame,Heyzap buttons to a group…Anchor it to BottomRight using side property.