含scrollView上控件坐标偏移量

- (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset
{
    NSLog(@"velocity.x    === %f, %f", velocity.x, velocity.y);
    NSLog(@"targetContentOffset ==== %f, %f", targetContentOffset->x, targetContentOffset->y);
    self.targetContentOffset_y = targetContentOffset->y;
}