UIScrollView下拉刷新跳动

scrollView.m

- (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset {
    
    CGFloat y = scrollView.contentOffset.y;
    if (y < -65) {

        [self.collectionView.mj_header beginRefreshing];
        // 消除刷新时functionView跳动的问题 动画时间不低于0.25s
        UIEdgeInsets inset = scrollView.contentInset;
        dispatch_async(dispatch_get_main_queue(), ^{
            [UIView animateWithDuration:0.25 animations:^{
                self.scrollView.contentInset = inset;
                [self.scrollView setContentOffset:CGPointMake(0, -inset.top) animated:NO];
            } completion:^(BOOL finished) {
            }];
        });
    } else if (y>0 && y<=kFunctionViewHeight) {
        [self setScrollViewAnimation:y];
    }
}