ScrollView的基本用法丶代理方法

- (void)viewDidLoad {
[super viewDidLoad];
_scrollView.backgroundColor = [UIColor redColor];
//设置contentSize（必须设置）
_scrollView.contentSize = CGSizeMake(400, 667);
//偏移量
_scrollView.contentOffset = CGPointMake(100, 0);
//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(50, 0, 50, 0);
//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(100, 200, 200, 300)];
[self.view addSubview:scrollView];

scrollView.backgroundColor = [UIColor redColor];
//设置内容视图的大小
scrollView.contentSize = CGSizeMake(375, 667);
//设置内容视图
UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 375, 667)];
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(0, 300) 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");
}