iOS实现图片轮播器

//（1）将需要展⽰的内容添加到UIScrollView中//（2）设置UIScrollView的contentSize属性,告诉UIScrollView所有内容的尺寸,也就是告诉 它滚动的范围(能滚多远,滚到哪⾥是尽头)#define imageCount 5#import "ViewController.h" @interface ViewController ()<UIScrollViewDelegate>@property (weak, nonatomic) IBOutlet UIScrollView *scrollView;@property (weak, nonatomic) IBOutlet UIPageControl *pageControl;@property(nonatomic,strong)NSTimer *timer; @end @implementation ViewController - (void)viewDidLoad{ [super viewDidLoad]; //1.添加5张图片到scrollView中 //设置图片frame,尺寸与scrollView一样高 CGFloat imageW=self.scrollView.frame.size.width; CGFloat imageH=self.scrollView.frame.size.height; //图片的具体位置需要动态计算 CGFloat imageY=0; for (int i=0; i<imageCount; i++) {  UIImageView *imageView=[[UIImageView alloc]init];  CGFloat imageX=i*imageW;  imageView.frame=CGRectMake(imageX, imageY, imageW, imageH);    //设置图片  NSString *name=[NSString stringWithFormat:@"img_0%d",i+1];  imageView.image=[UIImage imageNamed:name];    [self.scrollView addSubview:imageView]; }  //2.设置滚动内容的尺寸 CGFloat contentW=5*imageW; self.scrollView.contentSize=CGSizeMake(contentW, 0);  //3.隐藏水平的滚动条 self.scrollView.showsHorizontalScrollIndicator=NO;  //4.分页 self.pageControl.enabled=YES;  //5.设置代理 self.scrollView.delegate=self;  //6.设置pageControl的总页数 self.pageControl.numberOfPages=imageCount;  //7.添加定时器 self.timer=[NSTimer scheduledTimerWithTimeInterval:2.0 target:self selector:@selector(nextImage) userInfo:nil repeats:YES]; [[NSRunLoop currentRunLoop]addTimer:self.timer forMode:NSRunLoopCommonModes];}-(void)nextImage{ int page=0; if(self.pageControl.currentPage==imageCount-1) {  //如果滚动到最后一页了，那下一页就是第一页  page=0; } else {  //否则就是下一页  page=(int)self.pageControl.currentPage+1; }  //2.计算scrollView滚动的位置 CGFloat offsetX=page*self.scrollView.frame.size.width; CGPoint offset=CGPointMake(offsetX, 0); [self.scrollView setContentOffset:offset animated:YES];} //开始拖拽的时候调用-(void)scrollViewWillBeginDragging:(UIScrollView *)scrollView{ //停止定时器 [self.timer invalidate]; self.timer=nil;} //停止拖拽的时候调用-(void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate{ //再次开启定时器 self.timer=[NSTimer scheduledTimerWithTimeInterval:2.0 target:self selector:@selector(nextImage) userInfo:nil repeats:YES]; [[NSRunLoop currentRunLoop]addTimer:self.timer forMode:NSRunLoopCommonModes]; }//当scrollView正在滚动就会调用-(void)scrollViewDidScroll:(UIScrollView *)scrollView{ //根据scrollView的滚动位置决定pageControl显示第几页 int page=(scrollView.contentOffset.x+self.scrollView.frame.size.width*0.5)/scrollView.frame.size.width; self.pageControl.currentPage=page;}