判断scrlloview是否是向下滑动的

#pragma mark 判断页面是否是向下滑动的

-(void)scrollViewWillBeginDragging:(UIScrollView *)scrollView {

    CGPoint translation = [scrollView.panGestureRecognizer translationInView:scrollView.superview];

    if (translation.y>0) {

        [[NSNotificationCenterdefaultCenter]postNotificationName:@"downKeyWord"object:nil];

    }

 

}