[안드로이드] preferenceScreen 관련.

http://blog.naver.com/crowdark7?Redirect=Log&logNo=117994560 

 상세 설명 : 

http://tigerwoods.tistory.com/31   

 preferenceScreen 하단에 버튼 생성하기

 http://2younow.tistory.com/12 

http://www.androidpub.com/264529