navigationBar根据scrollview滚动显隐

1.修改滚动时navigationBar显隐

//遵守协议，设置代理

<UIScrollViewDelegate>

self.scView.delegate = self;

//声明UIScrollview对象scView

@property (nonatomic,strong)UIScrollView *scView;

//设置contentSize 保证scrollview可以滚动

self.scView.contentSize = CGSizeMake(ScreenWidth,ScreenHeight);

//调用代理方法，监听scrollview的滚动，设置navigationBar的显隐

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

    [self.navigationControllersetNavigationBarHidden:NOanimated:YES];

}

-(void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate{

    [self.navigationControllersetNavigationBarHidden:YESanimated:YES];

}

//调用代理方法，是先navigation bar得显隐

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

    [self.navigationControllersetNavigationBarHidden:NOanimated:YES];

}

-(void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate{

    [self.navigationControllersetNavigationBarHidden:YESanimated:YES];

}