- (void)viewDidLoad {

    [super viewDidLoad];

    _scrollView.backgroundColor = [UIColor redColor];

    //设置contentSize（必须设置）

    _scrollView.contentSize = CGSizeMake(, );

    //偏移量

    _scrollView.contentOffset = CGPointMake(, );

    //contentInset(在原有的基础上调整内容滚动区域的大小)

    //_scrollView.contentInset = UIEdgeInsetsMake(-100, 0, 0, 0);

    //锁定方向(当系统识别滚动方向的时候，会把另外一个方向锁定，如果识别不了，就不锁定方向)

    _scrollView.directionalLockEnabled = YES;

    //反弹效果(默认为yes)

    _scrollView.bounces = YES;

    //默认是no，假如是yes并且bounces是yes,甚至如果内容大小小于bounds的时候，允许垂直拖动

    _scrollView.alwaysBounceVertical = YES;

    //分页（默认no）

    _scrollView.pagingEnabled = YES;

    //滚动(默认yes允许滚动)

    _scrollView.scrollEnabled = YES;

    //滚动条

    //showsHorizontalScrollIndicator默认yes 显示

    _scrollView.showsHorizontalScrollIndicator = NO;

    //滚动条滚动的范围(垂直滚动条滚动范围上下各缩小50)

    _scrollView.scrollIndicatorInsets = UIEdgeInsetsMake(, , , );

    //样式

    _scrollView.indicatorStyle = UIScrollViewIndicatorStyleWhite;

    // Do any additional setup after loading the view, typically from a nib.

}

- (void)viewDidLoad {

    [super viewDidLoad];

    //创建并添加scrollView

    UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(, , , )];

    [self.view addSubview:scrollView];

    scrollView.backgroundColor = [UIColor redColor];

    //设置内容视图的大小

    scrollView.contentSize = CGSizeMake(, );

    //设置内容视图

    UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(, , , )];

    imageView.image = [UIImage imageNamed:@"new_feature_1"];

    [scrollView addSubview:imageView];

    _imageView = imageView;

    //设置代理

    scrollView.delegate = self;

    //[self performSelector:@selector(changeScrollViewContentOffSet:) withObject:scrollView afterDelay:3];

    //设置缩放内容视图的缩放比例范围

    scrollView.minimumZoomScale = 0.5;

    scrollView.maximumZoomScale = 1.5;

    //当缩放比例超出范围之后，是否有反弹效果（no:不会超出范围，yes:超出范围之后反弹）

    scrollView.bouncesZoom = YES;

    //属性设置滚动至顶部

    //scrollView.scrollsToTop = YES;

    // Do any additional setup after loading the view, typically from a nib.

}

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

    [scrollView setContentOffset:CGPointMake(, ) animated:YES];

}

#if 0

#pragma mark -UIScrollViewDelegate 滚动

//当scrollView滚动的时候，不停调用（可以监听scrollView的contentOffset）

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

    //NSLog(@"%@",NSStringFromCGPoint(scrollView.contentOffset));

    //NSLog(@"decelerating：%d",scrollView.decelerating);

    //NSLog(@"dragging：%d",scrollView.dragging);

    //NSLog(@"tracking:%d",scrollView.tracking);

    NSLog(@"%s",__func__);

}

//开始拖动的时候调用

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

    //NSLog(@"tracking:%d",scrollView.tracking);

    NSLog(@"%s",__func__);

}

// called on finger up if the user dragged. velocity is in points/millisecond. targetContentOffset may be changed to adjust where the scroll view comes to rest

//将要结束拖动

- (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset {

//    NSLog(@"velocity:%@",NSStringFromCGPoint(velocity));

//    NSLog(@"targetContentOffset:%@",NSStringFromCGPoint(*targetContentOffset));

    //强制设置scrollView的偏移量

    //*targetContentOffset = CGPointMake(0, 200);

    NSLog(@"%s",__func__);

}

// 已经结束拖动

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

    //NSLog(@"dragging：%d",scrollView.dragging);

    NSLog(@"%s",__func__);

}

//将要开始减速

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

    //NSLog(@"decelerating：%d",scrollView.decelerating);

    NSLog(@"%s",__func__);

}

//减速完成（停止）

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

    //NSLog(@"contentOffset:%@",NSStringFromCGPoint(scrollView.contentOffset));

    NSLog(@"%s",__func__);

}

// called when setContentOffset/scrollRectVisible:animated: finishes. not called if not animating

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

    NSLog(@"%s",__func__);

}

#endif

#pragma mark -UIScrollViewDelegate(缩放)

//指定缩放视图

- (nullable UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView{

    NSLog(@"%s,zooming:%d",__func__,scrollView.zooming);

    return _imageView;

}

//缩放之前调用

- (void)scrollViewWillBeginZooming:(UIScrollView *)scrollView withView:(nullable UIView *)view {

    NSLog(@"%s,zooming:%d",__func__,scrollView.zooming);

}

//完成缩放

- (void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(nullable UIView *)view atScale:(CGFloat)scale{

    NSLog(@"%s,zooming:%d",__func__,scrollView.zooming);

}

//缩放时调用

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

    NSLog(@"%s,zooming:%d",__func__,scrollView.zooming);

}

#pragma mark -UIScrollViewDelegate(滚动至顶部)

//允许滚动至顶部

- (BOOL)scrollViewShouldScrollToTop:(UIScrollView *)scrollView{

    return YES;

}

//已经滚动至顶部

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

    NSLog(@"加载新数据，刷新界面");

}