In the history of smartphones, the revolutionary technologies have made a agreat transformation from the giant brick-structure smartphones in 1995 to slim and stylish form factor nowadays. Over the past few decades ago, smartphones become more abundant, for instance, 300 million units were sold world-wide in 2010  while one out of two Americans started using smartphones mobile phones in the year 2011 . This has caused Smart mobile operating system (OS) to become a blazing hot issue, after Apple reintroduced the term “Smart” in a phone in the year 2007. An Android phone manufacturer, Samsung, sold 319.8 million units 32.2 percent, a 15% increase from 2012 whereas Apple sold 153.5 million iPhones worldwide with a 15.5 % market share. In the year 2013 alone, global smart phones shipments boost up 41 percent to reach a record-high 990 million units according to the Thomson Reuters, the world's largest international multimedia news.
However, under the hood of market statistics, an enormous technical progress has been made since the inception of mobile devices. As the performance of the mobile device becomes significantly increased, the potential use of such devices is also tremendous. As a result, the developers are now facing the challenge of designing not only hardware architectures but also complex software. One of the most challenging problems is to design a well usable smartphone. For instance, the process of designing the graphical user interface of a