android 색상 alpha값 적용

android:background="#80000000"

80 : 알파값

000000 : 0-255 색상값 

알파 적용

100% — FF

90% — E6

80% — CC

70% — B3

60% — 99

50% — 80

40% — 66

30% — 4D

20% — 33

10% — 1A

0% — 00