White or black text based on background colour

ColorUtil.java

import android.graphics.Color;

/**
 * Created by lhtan on 24/8/15.
 * Based on How to decide font color in white or black depending on background color?
 * http://stackoverflow.com/questions/3942878/how-to-decide-font-color-in-white-or-black-depending-on-background-color
 */
public class ColorUtil {
    /**
     * compute text color, either white or black based on colorString
     * @param colorString color string in format #XXXXXX
     * @return int Color.WHITE or Color.BLACK based on the colorString
     */
    public static int computeTextColorFromBackgroundColor1(String colorString){
        long color = Long.parseLong(colorString.substring(1), 16);
        if (colorString.length() == 7) {
            final int r = (int)((color & 0x0000000000ff0000) >> 16);
            final int g = (int)((color & 0x000000000000ff00) >> 8);
            final int b = (int)(color & 0x00000000000000ff);
            if ((r*0.299 + g*0.587 + b*0.114) > 186){
                return Color.BLACK;
            }else{
                return Color.WHITE;
            }
        } else if (colorString.length() != 9) {
            throw new IllegalArgumentException("Unknown color");
        }
        return Color.WHITE;
    }
    public static int computeTextColorFromBackgroundColor2(String colorString){
        long color = Long.parseLong(colorString.substring(1), 16);
        if (colorString.length() == 7) {
            final int r = (int)((color & 0x0000000000ff0000) >> 16);
            final int g = (int)((color & 0x000000000000ff00) >> 8);
            final int b = (int)(color & 0x00000000000000ff);
            double rd = gammaCorrect(r);
            double gd = gammaCorrect(g);
            double bd = gammaCorrect(b);
            double luminance = 0.2126 * rd + 0.7152 * gd + 0.0722 * bd;
            if(luminance > 0.179){
                return Color.BLACK;
            }else {
                return Color.WHITE;
            }
        } else if (colorString.length() != 9) {
            throw new IllegalArgumentException("Unknown color");
        }
        return Color.WHITE;
    }
    private static double gammaCorrect(int value){
        double c = value/255.0;
        if (c <= 0.03928){
            c = c/12.92;
        } else {
            c = Math.pow(((c+0.055)/1.055), 2.4);
        }
        return c;
    }
}