#import "NYViewController.h"#define kImageCount 5@interface NYViewController () <UIScrollViewDelegate>
@property (nonatomic, strong) UIScrollView *scrollView;
@property (nonatomic, strong) UIPageControl *pageControl;@property (nonatomic, strong) NSTimer *timer;
@end@implementation NYViewController//懒加载加载scrollView
-(UIScrollView *)scrollView
{if (_scrollView == nil) {_scrollView = [[UIScrollView alloc]initWithFrame:CGRectMake(10, 20, 300, 130)];_scrollView.backgroundColor = [UIColor redColor];[self.view addSubview:_scrollView];//contentSize//高度为0 只水平滚动self.scrollView.contentSize = CGSizeMake(kImageCount * _scrollView.bounds.size.width, 0);//取消弹簧效果_scrollView.bounces = NO;//取消滚动条_scrollView.showsHorizontalScrollIndicator = NO;//水平_scrollView.showsVerticalScrollIndicator = NO;//竖直//要分页_scrollView.pagingEnabled = YES;//设置代理_scrollView.delegate = self;}return _scrollView;
}-(UIPageControl *)pageControl
{if (_pageControl == nil) {//分页控件，本质上和scrollView没有任何关系，是两个独立的控件_pageControl = [[UIPageControl alloc]init];//总页数_pageControl.numberOfPages = kImageCount;//控件尺寸CGSize size = [_pageControl sizeForNumberOfPages:kImageCount];_pageControl.bounds = CGRectMake(0, 0, size.width, size.height);_pageControl.center = CGPointMake(self.view.center.x, 130);//设置颜色_pageControl.pageIndicatorTintColor = [UIColor redColor];_pageControl.currentPageIndicatorTintColor = [UIColor blackColor];[self.view addSubview:_pageControl];//添加监听方法/**在OC中，绝大多数“继承UIControl控件”，都可以监听UIControlEventValueChanged事件，只有button除外，button是点得，是touchup。。。*/[_pageControl addTarget:self action:@selector(pageChanged:) forControlEvents:UIControlEventValueChanged];}return _pageControl;
}//分页控件的监听方法
-(void)pageChanged:(UIPageControl *)page
{//根据页数，调整滚动视图中得图片位置contentOffsetCGFloat x = page.currentPage * self.scrollView.bounds.size.width;[self.scrollView setContentOffset:CGPointMake(x, 0) animated:YES];
}- (void)viewDidLoad
{[super viewDidLoad];//设置图片for (int i = 0; i<kImageCount; i++) {NSString *imageName = [NSString stringWithFormat:@"img_%02d", i+1 ];UIImage *image = [UIImage imageNamed:imageName];UIImageView *imageView = [[UIImageView alloc] initWithFrame: self.scrollView.bounds];imageView.image = image;[self.scrollView addSubview:imageView];}//计算imageView的位置[self.scrollView.subviews enumerateObjectsUsingBlock:^(UIImageView *imageView, NSUInteger idx, BOOL *stop) {//调整x =》 origin =》frameCGRect frame = imageView.frame;frame.origin.x = idx * frame.size.width;imageView.frame = frame;}];//分页初始页数为0self.pageControl.currentPage = 0;//启动时钟
    [self startTimer];}/**启动时钟*/
-(void)startTimer
{self.timer = [NSTimer scheduledTimerWithTimeInterval:2.0 target:self selector:@selector(updateTimer) userInfo:nil repeats:YES];//添加运行循环
    [[NSRunLoop currentRunLoop]addTimer:self.timer forMode:NSRunLoopCommonModes];}-(void)updateTimer
{//页号发生变化//（当前页数 + 1） % 总页数int page = (self.pageControl.currentPage+1) % kImageCount;self.pageControl.currentPage = page;//调用监听方法。让滚动视图滚动
    [self pageChanged:self.pageControl];
}#pragma mark - scrollView的代理方法//滚动视图停下来
-(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{// 停下来的当前页数,通过contentOffset获取当前偏移量NSLog(@"%@",NSStringFromCGPoint(scrollView.contentOffset));//计算页数int page = scrollView.contentOffset.x/scrollView.bounds.size.width;self.pageControl.currentPage = page;}/**抓住图片时，停止时钟，松手后，开启时钟*/
-(void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{//停止时钟，停止后就不能在使用，如果要启用时钟，需要重新实例化
    [self.timer invalidate];
}-(void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate
{//启动时钟
    [self startTimer];}
@end