如何在Java中使用UUID生成颜色代码

Question

I want to create random color code with UUID in java, and i could not find best code for my problem.

Sample code for C# with GUID

public static Color ColorFromGuid(UUID id)
{
    var values = id.ToByteArray().Select(b => (int)b);
    int red = values.Take(5).Sum() % 255;
    int green = values.Skip(5).Take(5).Sum() % 255;
    int blue = values.Skip(10).Take(5).Sum() % 255;

    Color color = Color.FromArgb(200, red, green, blue);
    return color;
}

Answer 1

Here is an alternative :

        public static void main(String[] args) {

            getRandomColor(UUID.randomUUID());

        }

        /**
         * Method return a random color.
         */
        public static Color getRandomColor(UUID id) {

            byte[] bytes = UUID2Bytes(id);

            int r= Math.abs(bytes[0]);
            int g = Math.abs(bytes[1]);
            int b = Math.abs(bytes[2]);

            return  new Color(r, g, b);
        }

        public static byte[] UUID2Bytes(UUID uuid) {

            long hi = uuid.getMostSignificantBits();
            long lo = uuid.getLeastSignificantBits();
            return ByteBuffer.allocate(16).putLong(hi).putLong(lo).array();
        }

Answer 2

Answer for Android

 public  int getRandomColor(UUID id) {

        byte[] bytes = UUID2Bytes(id);

        int r= Math.abs(bytes[0]);
        int g = Math.abs(bytes[1]);
        int b = Math.abs(bytes[2]);
        int color = Color.argb(255, r, g, b);
        Log.e("Color",color+"");
        return  color;
    }

    public  byte[] UUID2Bytes(UUID uuid) {

        long hi = uuid.getMostSignificantBits();
        long lo = uuid.getLeastSignificantBits();
        Log.e("UUID2Bytes",hi+"  "+lo);
        return ByteBuffer.allocate(16).putLong(hi).putLong(lo).array();
    }

Answer 3

You can do something like this:

public static Color colorFromGuid(UUID uuid) {
    ByteBuffer bb = ByteBuffer.wrap(new byte[8]);
    bb.putLong(uuid.getLeastSignificantBits());
    int red = bb.get(0) & 0xff;
    int green = bb.get(1) & 0xff;
    int blue = bb.get(2) & 0xff;
    int alpha = bb.get(3) & 0xff;

    Color color = new Color(red, green, blue, alpha);
    return color;
}

You could also use the most significant bits from the UUID and generate 4 colours from each one, since this is only using a quarter half of the bits.

[Edited to only use 1 byte for each colour component.]