Androiod RecycleView的滑动实现标题栏透明度渐变

1.注意：透明度都是[0,255]/**
* 设置标题栏背景透明度
* @param alpha 透明度
*/
private void setSystemBarAlpha(int alpha) {
if (alpha >= 225) {
alpha = 255;
}
text.getBackground().setAlpha(alpha);
}2.标题栏并使它默认为全透明setSystemBarAlpha(0);3.监听recycleview的滑动事件rcy_hangqing.addOnScrollListener(mOnScrollListener);

//滑动监听事件
RecyclerView.OnScrollListener mOnScrollListener = new RecyclerView.OnScrollListener() {
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
int alpha = rcy_hangqing.computeVerticalScrollOffset();
setSystemBarAlpha(alpha);
}
};