ColorUtils.java

public class ColorUtils {

    private static final float DEFAULT_LIGHTNESS_ADJUST_PERCENTAGE = 0.2f;
    
    public static boolean isFlagshipLight(@ColorInt int color) {
        return getBrightness(color) >= 204.0f;
//        return getLightness(color) > 0.5f;
//        return getContrast(color, Color.BLACK) > 4.5;
    }

    public static int lightenOrDarken(int color) {
        return lightenOrDarken(color, DEFAULT_LIGHTNESS_ADJUST_PERCENTAGE);
    }
    
    public static int lightenOrDarken(int color, float percentage) {
        if (getLightness(color) > 0.5f) {
            return darken(color, percentage);
        } else {
            return lighten(color, percentage);
        }
    }
    
    /**
     * Formula defined
     * <a href="https://www.w3.org/WAI/ER/WD-AERT/#color-contrast">here</a>
     */
    private static float getBrightness(@ColorInt int color) {
        int r = Color.red(color);
        int g = Color.green(color);
        int b = Color.blue(color);

        return ((r * 299) + (g * 587) + (b * 114)) / 1000.0f;
    }

    private static float getLightness(@ColorInt int color) {
        float[] hsl = new float[3];
        ColorUtils.colorToHSL(color, hsl);
        return hsl[2];
    }

    private static int lighten(@ColorInt int color, float percentage) {
        float[] hsl = new float[3];
        ColorUtils.colorToHSL(color, hsl);
        hsl[2] = constrain(hsl[2] + percentage, 0f, 1f);
        return ColorUtils.HSLToColor(hsl);
    }

    private static int darken(@ColorInt int color, float percentage) {
        float[] hsl = new float[3];
        ColorUtils.colorToHSL(color, hsl);
        hsl[2] = constrain(hsl[2] - percentage, 0f, 1f);
        return ColorUtils.HSLToColor(hsl);
    }
    
    private static float constrain(float amount, float low, float high) {
        return amount < low ? low : (amount > high ? high : amount);
    }
    
    /**
     * WCAG 2.0
     * level AA requires a contrast ratio of 4.5:1 for normal text and 3:1 for large text.
     * Level AAA requires a contrast ratio of 7:1 for normal text and 4.5:1 for large text.
     *
     * Large text is defined as 14 point (typically 18.66px) and bold or larger, or 18 point (typically 24px) or larger.
     *
     * <a href="http://webaim.org/resources/contrastchecker">reference</a>
     */
    private static double getContrast(@ColorInt int foreground, @ColorInt int background) {
        // [1:21]
        return ColorUtils.calculateContrast(foreground, background);
    }
    
    public static int[] colorToARGB(@ColorInt int color) {
        return new int[]{Color.alpha(color), Color.red(color), Color.green(color), Color.blue(color)};
    }

    public static int[] getGradientARGB(@ColorInt int start, @ColorInt int end, @IntRange(from = 2) int step) {
        if (step <= 2) {
            return new int[]{start, end};
        }

        int[] gradient = new int[step];
        gradient[0] = start;
        gradient[step - 1] = end;

        int[] startArgb = colorToARGB(start);
        int[] endArgb = colorToARGB(end);

        int interval = step - 1;
        float[] intervalArgb = new float[]{
                (endArgb[0] - startArgb[0]) / (float) interval,
                (endArgb[1] - startArgb[1]) / (float) interval,
                (endArgb[2] - startArgb[2]) / (float) interval,
                (endArgb[3] - startArgb[3]) / (float) interval
        };

        for (int i = 1; i < interval; i++) {
            gradient[i] = Color.argb(
                    startArgb[0] + (int) (intervalArgb[0] * i),
                    startArgb[1] + (int) (intervalArgb[1] * i),
                    startArgb[2] + (int) (intervalArgb[2] * i),
                    startArgb[3] + (int) (intervalArgb[3] * i)
            );
        }

        return gradient;
    }
}

You can also use ColorUtils.blendARGB(originalColor, Color.WHITE, 0.2f); if you want to make a color lighter or ColorUtils.blendARGB(originalColor, Color.BLACK, 0.2f); if you want to make a color darker.

Cool! Let me check if they have the same result.