ArgbEvaluatorHolder.java

package com.example.administrator.cookman.ui.component.magicindicator.buildins;


/**
 * 实现颜色渐变，考虑到兼容性，不使用内置的ArgbEvaluator
 * 博客: http://hackware.lucode.net
 * Created by hackware on 2016/6/26.
 */
public class ArgbEvaluatorHolder {
    public static Object eval(float fraction, Object startValue, Object endValue) {
        int startInt = (Integer) startValue;
        int startA = (startInt >> 24) & 0xff;
        int startR = (startInt >> 16) & 0xff;
        int startG = (startInt >> 8) & 0xff;
        int startB = startInt & 0xff;

        int endInt = (Integer) endValue;
        int endA = (endInt >> 24) & 0xff;
        int endR = (endInt >> 16) & 0xff;
        int endG = (endInt >> 8) & 0xff;
        int endB = endInt & 0xff;

        int currentA = (startA + (int) (fraction * (endA - startA))) << 24;
        int currentR = (startR + (int) (fraction * (endR - startR))) << 16;
        int currentG = (startG + (int) (fraction * (endG - startG))) << 8;
        int currentB = startB + (int) (fraction * (endB - startB));

        return currentA | currentR | currentG | currentB;
    }
}