自己写的一个图片轮播器

#import "ViewController.h"

@interface ViewController () <UIScrollViewDelegate>
/**
 *  图片轮播器
 */
@property (nonatomic ,weak  ) UIScrollView    *scrView;
/**
 *  页面指示器
 */
@property (nonatomic, weak  ) UIPageControl   *pgControl;
/**
 *  计时器
 */
@property (nonatomic, strong) NSTimer         *timer;
@end

@implementation ViewController
- (void)viewDidLoad
{
    [super viewDidLoad];
    //加载图片轮播器
    [self setUpScrView];
    //加载页面指示器
    [self setUpPageControl];
    //加载定时器
    [self setUpTimer];
}
- (void)setUpScrView
{
    UIScrollView *scrView                  = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 64, self.view.frame.size.width, 250)];
    scrView.alwaysBounceHorizontal         = YES;
    scrView.showsHorizontalScrollIndicator = NO;
    scrView.pagingEnabled                  = YES;
    scrView.contentSize                    = CGSizeMake(self.view.frame.size.width * 5, 250);
    _scrView                               = scrView;
    [self setUpImg];
    [self.view addSubview:_scrView];
}

- (void)setUpPageControl
{
    UIPageControl *pgControl                = [[UIPageControl alloc] initWithFrame:CGRectMake(0, 0, self.view.bounds.size.width, 32)];
    pgControl.center                        = CGPointMake(CGRectGetMidX(self.view.bounds), 300);
    pgControl.currentPage                   = 0;
    pgControl.numberOfPages                 = 5;
    pgControl.currentPageIndicatorTintColor = [UIColor redColor];
    pgControl.pageIndicatorTintColor        = [UIColor greenColor];
    _pgControl                              = pgControl;
    [self.view addSubview:_pgControl];
}

- (void)scrollImage
{
    NSInteger page = _pgControl.currentPage;
    if (page == _pgControl.numberOfPages - 1) {
        page = 0;
    } else {
        page ++;
    }
    CGFloat offsetX = page * _scrView.frame.size.width;
    [_scrView setContentOffset:CGPointMake(offsetX, 0) animated:YES];

    _pgControl.currentPage = page;
}

- (void)setUpTimer
{
    _timer             = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(scrollImage) userInfo:nil repeats:YES];
    NSRunLoop *runloop = [NSRunLoop currentRunLoop];
    [runloop addTimer:_timer forMode:NSRunLoopCommonModes];
}

- (void)setUpImg
{
    CGFloat imgW = self.view.bounds.size.width;
    CGFloat imgH = 250;
    CGFloat imgY = 0;
    for (int i = 0; i < 5; i ++) {
        CGFloat imgX = imgW * i;
        UIImageView *imgView = [[UIImageView alloc] init];
        imgView.image        = [UIImage imageNamed:[NSString stringWithFormat:@"img_%02d", i + 1]];
        imgView.frame        = CGRectMake(imgX, imgY, imgW, imgH);
        [_scrView addSubview:imgView];
    }
}

#pragma mark UIScrollView代理方法
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    CGFloat offsetX        = _scrView.contentOffset.x;
    offsetX                += _scrView.frame.size.width / 2;
    NSInteger page         = offsetX / _scrView.frame.size.width;
    _pgControl.currentPage = page;
}

- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
    [_timer invalidate];
    _timer = nil;
}

- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate
{
    [self setUpTimer];
}

@end