A color int always defines a color in the sRGB color space using 4 components packed in a single 32 bit integer value:
Component Name Size Range A Alpha 8 bits [0..255] R Red 8 bits [0..255] G Green 8 bits [0..255] B Blue 8 bits [0..255] The components in this table are listed in encoding order (see below), which is why color ints are called ARGB colors.
Android 中的颜色值包含透明度（transparency），格式是为 #AARRGGBB，AA 就是透明度值，即 alpha 值。 透明度分为从 0 到 255 共 256 个等级，0 就是透明，255 就是不透明，对应着 16 进制（透明）00 -> FF（不透明）。
我们的设计师喜欢用 百分比 标注 不透明度（opacity），虽然网上有换算工具 Percent to Hex，但不少人都懒得算（比如我），那么就直接存一份百分比与对应的 16 进制字串好了。
100% - FF 不透明
99% - FC
98% - FA
97% - F7
96% - F5
95% - F2
94% - F0
93% - ED
92% - EB
91% - E8
90% - E6
89% - E3
88% - E0
87% - DE
86% - DB
85% - D9
84% - D6
83% - D4
82% - D1
81% - CF
80% - CC
79% - C9
78% - C7
77% - C4
76% - C2
75% - BF
74% - BD
73% - BA
72% - B8
71% - B5
70% - B3
69% - B0
68% - AD
67% - AB
66% - A8
65% - A6
64% - A3
63% - A1
62% - 9E
61% - 9C
60% - 99
59% - 96
58% - 94
57% - 91
56% - 8F
55% - 8C
54% - 8A
53% - 87
52% - 85
51% - 82
50% - 80 半透明
49% - 7D
48% - 7A
47% - 78
46% - 75
45% - 73
44% - 70
43% - 6E
42% - 6B
41% - 69
40% - 66
39% - 63
38% - 61
37% - 5E
36% - 5C
35% - 59
34% - 57
33% - 54
32% - 52
31% - 4F
30% - 4D
29% - 4A
28% - 47
27% - 45
26% - 42
25% - 40
24% - 3D
23% - 3B
22% - 38
21% - 36
20% - 33
19% - 30
18% - 2E
17% - 2B
16% - 29
15% - 26
14% - 24
13% - 21
12% - 1F
11% - 1C
10% - 1A
9% - 17
8% - 14
7% - 12
6% - 0F
5% - 0D
4% - 0A
3% - 08
2% - 05
1% - 03
0% - 00 全透明
