1.想实现的效果：

浏览文章的时候，当向下滑动时候，navigationBar 和 toolbar 隐藏 , 当到结尾时候再向上滑动，navigationBar 和 toolbar 重新显示出来。

2.思路：

首先，这里用来显示文章的是webview ，我们都知道webview中包含scrollview，这样就好办了，我们利用scrollview来实现即可。

 

代码如下:

#pragma mark - UIScrollViewDelegate- (void)scrollViewDidScroll:(UIScrollView *)scrollView{    int currentPostion = scrollView.contentOffset.y;    if (currentPostion - lastPostion > kSlide && currentPostion > 0) {        lastPostion = currentPostion;                //重设frame        [UIView animateWithDuration:kAnimationTime animations:^{            CGRect rc = self.navigationController.navigationBar.frame;            self.navigationController.navigationBar.frame = CGRectMake(0, -CGRectGetHeight(rc), CGRectGetWidth(rc), CGRectGetHeight(rc));                        rc= self.toolbar.frame;            self.toolbar.frame = CGRectMake(0, [UIScreen mainScreen].bounds.size.height, CGRectGetWidth(rc), CGRectGetHeight(rc));                    self.webView.frame = CGRectMake(0, 0, [UIScreen mainScreen].bounds.size.width, [UIScreen mainScreen].bounds.size.height);        }];    }    else if (lastPostion - currentPostion > kSlide && (currentPostion  <= scrollView.contentSize.height-scrollView.bounds.size.height-kSlide))    {        lastPostion = currentPostion;                //重设frame        [UIView animateWithDuration:kAnimationTime animations:^{            CGRect rc = self.navigationController.navigationBar.frame;            self.navigationController.navigationBar.frame = CGRectMake(0, 0, CGRectGetWidth(rc), CGRectGetHeight(rc));                        rc= self.toolbar.frame;            self.toolbar.frame = CGRectMake(0, [UIScreen mainScreen].bounds.size.height - CGRectGetHeight(rc), CGRectGetWidth(rc), CGRectGetHeight(rc));                        self.webView.frame = CGRectMake(0, CGRectGetHeight(self.navigationController.navigationBar.frame), [UIScreen mainScreen].bounds.size.width, [UIScreen mainScreen].bounds.size.height - CGRectGetHeight(self.navigationController.navigationBar.frame) - CGRectGetHeight(rc));        }];    }    }

 

 

ps:不要忘记设置

self.webView.scrollView.delegate = self;

demo示例: