6. 참조
O Stop Watch : thread, handler, List View
http://blog.naver.com/khs7515/20155818207
List View 역순정렬
http://devbible.tistory.com/23
O Stop Watch : switch
http://gwpark.tistory.com/1996
O GIF : thread, handler
http://droid-blog.net/2011/10/15/tutorial-how-to-play-
animated-gifs-in-android-%E2%80%93-part-2/
http://gwpark.tistory.com/1996
O Landscape 초기화 방지
http://sonseungha.tistory.com/268