ColorUtils.java

import android.graphics.Color;
import android.support.annotation.ColorInt;
import android.support.annotation.FloatRange;

public final class ColorUtils {
    public static int blendColors(
            @ColorInt int firstColor,
            @ColorInt int secondColor,
            @FloatRange(from = 0.0, to = 1.0f) float percentage) {
        int firstAlpha = Color.alpha(firstColor);
        int firstRed = Color.red(firstColor);
        int firstGreen = Color.green(firstColor);
        int firstBlue = Color.blue(firstColor);

        int secondAlpha = Color.alpha(secondColor);
        int secondRed = Color.red(secondColor);
        int secondGreen = Color.green(secondColor);
        int secondBlue = Color.blue(secondColor);

        float inversePercentage = 1 - percentage;
        return Color.argb((int) Math.abs((inversePercentage * firstAlpha) + (percentage * secondAlpha)),
                (int) Math.abs((inversePercentage * firstRed) + (percentage * secondRed)),
                (int) Math.abs((inversePercentage * firstGreen) + (percentage * secondGreen)),
                (int) Math.abs((inversePercentage * firstBlue) + (percentage * secondBlue)));
    }

    private ColorUtils() {
    }
}