UIScrollerView常见属性
CGPoint contentOffset
这个属性用来表示UIScrollerView滚动的位置（其实就是内容左上角与ScrollerView左上角的间距值）CGSize contentSize
这个属性用来表示UIScrollerView内容尺寸，滚动范围（能滚多远）UIEdgeInsets contentInset
这个属性能够在UIScrollerView的四周增加额外的滚动区域，一般用来避免scrollerView的内容被其他控件挡住
UIScrollerView无法滚动的原因
- 没有设置contentSize
- scrollEnabled = NO
- 没有收到触摸事件：ueserInteractionEnabled = NO
UIScrollerView代理方法
- ScrollerView滑动的代理回调
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView{
NSLog(@"即将开始滑动内容时");
}
- (void)scrollViewDidScroll:(UIScrollView *)scrollView{
NSLog(@"正在滑动");
}
- (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset{
NSLog(@"当用户完成滑动内容时");
}
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate{
NSLog(@"结束滑动");
}
- (void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView{
NSLog(@"将开始减速");
}
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{
NSLog(@"减速完毕，停止滑动");
}
- ScrollerView缩放的代理回调
必须设置scrollerView的缩放比例
scrollerView.maximumZoomScale = 2.0;
scrollerView.minimumZoomScale = 0.2;
- (void)scrollViewWillBeginZooming:(UIScrollView *)scrollView withView:(nullable UIView *)view{
NSLog(@"开始缩放");
}
- (void)scrollViewDidZoom:(UIScrollView *)scrollView{
NSLog(@"缩放");
}
- (void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(nullable UIView *)view atScale:(CGFloat)scale{
NSLog(@"结束缩放");
}
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView{
return [UIView new];
}
- ScrollerView缩放的代理回调
//滚动视图在和方法的实现结束时调用此方法，但仅在请求动画时调用setContentOffset:animated:scrollRectToVisible:animated:
- (void)scrollViewDidEndScrollingAnimation:(UIScrollView *)scrollView{
NSLog(@"结束缩放动画");
}
- (BOOL)scrollViewShouldScrollToTop:(UIScrollView *)scrollView{
NSLog(@"点击状态栏是否可以回到顶部");
return YES;
}
//scrollViewShouldScrollToTop设置为YES，滚动视图在完成滚动到内容顶部时发送此消息
- (void)scrollViewDidScrollToTop:(UIScrollView *)scrollView{
NSLog(@"滚动视图在完成滚动到内容顶部时发送此消息");
}
UIScrollerView分页（电商与新闻常用）
简单示例.gif
@interface ScrollViewPage ()<UIScrollViewDelegate>
@property (nonatomic,strong) UIImageView *imageView;
@property (nonatomic,strong) UIScrollView *scrollerView;
@property (nonatomic,strong) UIPageControl *pageControl;
@end
@implementation ScrollViewPage
- (void)viewDidLoad {
[super viewDidLoad];
UIView *view = [[UIView alloc]initWithFrame:CGRectMake(0, 64, self.view.bounds.size.width, 230)];
view.backgroundColor = [UIColor whiteColor];
[self.view addSubview:view];
[self loadScrollViewCon:view];
[self loadPageCon:view];
}
- (void)loadScrollViewCon:(UIView *)view{
self.scrollerView = [[UIScrollView alloc]initWithFrame:CGRectMake(0,0, view.bounds.size.width, 230)];
self.scrollerView.delegate = self;
[self.scrollerView setShowsVerticalScrollIndicator:NO];
[self.scrollerView setShowsHorizontalScrollIndicator:NO];
CGFloat w = self.scrollerView.bounds.size.width;
CGFloat h = self.scrollerView.bounds.size.height;
NSInteger pageCount = 5;
for (int i = 0; i < pageCount; i++) {
UIImageView *imageView = [[UIImageView alloc]initWithImage:[UIImage imageNamed:[NSString stringWithFormat:@"pic%d",i]]];
[imageView setFrame:CGRectMake(w*i, 0, w, h)];
[self.scrollerView addSubview: imageView];
}
//设置内容视图大小
[self.scrollerView setContentSize:CGSizeMake(w*pageCount, 0)];
//开启分页
[self.scrollerView setPagingEnabled:YES];
[view addSubview:self.scrollerView];
}
- (void)loadPageCon:(UIView *)view{
self.pageControl = [[UIPageControl alloc]initWithFrame:CGRectMake(view.bounds.size.width-200, view.bounds.size.height-20, 200, 20)];
self.pageControl.numberOfPages = 5;
self.pageControl.pageIndicatorTintColor = [UIColor orangeColor];
self.pageControl.currentPageIndicatorTintColor = [UIColor grayColor];
[view addSubview:self.pageControl];
}
#pragma mark- scrollViewDelegate
- (void)scrollViewDidScroll:(UIScrollView *)scrollView{
//0.3 > (int)(0.3+0.5) > 0
//0.3 > (int)(0.3+0.5) > 0
//小数四舍五入为整数：（int）(小数 + 0.5)
NSInteger page = (int)(self.scrollerView.contentOffset.x / self.view.frame.size.width + 0.5);
self.pageControl.currentPage = page;
NSLog(@"%zd",page);
}
@end
