android 颜色(color)

SDK文档定义如下:

The Color class defines methods for creating and converting color ints. Colors are represented as packed ints, made up of 4 bytes: alpha, red, green, blue. The values are unpremultiplied, meaning any transparency is stored solely in the alpha component, and not in the color components. The components are stored as follows (alpha << 24) | (red << 16) | (green << 8) | blue. Each component ranges between 0..255 with 0 meaning no contribution for that component, and 255 meaning 100% contribution. Thus opaque-black would be 0xFF000000 (100% opaque but no contributions from red, green, or blue), and opaque-white would be 0xFFFFFFFF

Alpha通道是一个8位的灰度通道，该通道用256级灰度来记录图像中的透明度信息，定义透明、不透明和半透明区域，其中黑表示全透明，白表示不透明，灰表示半透明。

public static final int BLACK

Since: API Level 1

Constant Value: -16777216 (0xff000000)

public static final int BLUE

Since: API Level 1

Constant Value: -16776961 (0xff0000ff)

public static final int CYAN

Since: API Level 1

Constant Value: -16711681 (0xff00ffff)

public static final int DKGRAY

Since: API Level 1

Constant Value: -12303292 (0xff444444)

public static final int GRAY

Since: API Level 1

Constant Value: -7829368 (0xff888888)

public static final int GREEN

Since: API Level 1

Constant Value: -16711936 (0xff00ff00)

public static final int LTGRAY

Since: API Level 1

Constant Value: -3355444 (0xffcccccc)

public static final int MAGENTA

Since: API Level 1

Constant Value: -65281 (0xffff00ff)

public static final int RED

Since: API Level 1

Constant Value: -65536 (0xffff0000)

public static final int TRANSPARENT

Since: API Level 1

Constant Value: 0 (0x00000000)

public static final int WHITE

Since: API Level 1

Constant Value: -1 (0xffffffff)

public static final int YELLOW

Since: API Level 1

Constant Value: -256 (0xffffff00)