計算其滑動距離
- (void)scrollViewDidScroll:(UIScrollView *)scrollView{
if ([self.collectionView isEqual:scrollView]) {
//計算偏移量
CGFloat offsetX = self.collectionView.contentOffset.x;
//150----滾動條的總長度
CGFloat X = offsetX*(150-self.line.frame.size.width)/(self.collectionView.contentSize.width-self.collectionView.frame.size.width);
[self.line mas_updateConstraints:^(MASConstraintMaker *make) {
make.left.mas_equalTo(X);
}];
[self.line.superview layoutIfNeeded];
}
}
