MaterialViewPagerAnimator.java 文件源码

/**
 * Change the color of the statusbackground, toolbar, toolbarlayout and pagertitlestrip
 * With a color transition animation
 *
 * @param color    the final color
 * @param duration the transition color animation duration
 */
void setColor(int color, int duration) {
    final ValueAnimator colorAnim = ObjectAnimator.ofInt(mHeader.headerBackground, "backgroundColor", settings.color, color);
    colorAnim.setEvaluator(new ArgbEvaluator());
    colorAnim.setDuration(duration);
    colorAnim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
        @Override
        public void onAnimationUpdate(ValueAnimator animation) {
            final int animatedValue = (Integer) animation.getAnimatedValue();
            int colorAlpha = colorWithAlpha(animatedValue, lastPercent);
            mHeader.headerBackground.setBackgroundColor(colorAlpha);
            mHeader.statusBackground.setBackgroundColor(colorAlpha);
            mHeader.toolbar.setBackgroundColor(colorAlpha);
            mHeader.toolbarLayoutBackground.setBackgroundColor(colorAlpha);
            mHeader.mPagerSlidingTabStrip.setBackgroundColor(colorAlpha);

            //set the new color as MaterialViewPager's color
            settings.color = animatedValue;
        }
    });
    colorAnim.start();
}