-(void)scrollViewDidScroll:(UIScrollView *)scrollView
{
footbutton.frame = CGRectMake(footbutton.frame.origin.x, WINDOW_HEIGHT-49+self.collectionView.contentOffset.y , footbutton.frame.size.width, footbutton.frame.size.height);
}
-(void)scrollViewDidScroll:(UIScrollView *)scrollView
{
footbutton.frame = CGRectMake(footbutton.frame.origin.x, WINDOW_HEIGHT-49+self.collectionView.contentOffset.y , footbutton.frame.size.width, footbutton.frame.size.height);
}