滚动视图+分页控制器+定时器

#import "ViewController.h"
@interface ViewController ()
{
    UIScrollView *_scrollView;
    UIPageControl *_pageControl;
    NSTimer *_timer;
    int _speed;
}

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    //创建
    [self createScrollView];
    //创建pagecontrol
    UIPageControl *pageControl = [self pageControl];
    [self.view addSubview:pageControl];
    _speed = 1;
    _timer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(ontimer) userInfo:nil repeats:YES];
}

#pragma mark --- createScrollview
-(void)createScrollView
{
    _scrollView = [[UIScrollView alloc]  initWithFrame:CGRectMake(0, 20, 320, 200)];
    //设置滚动视图内容的大小
    _scrollView.contentSize = CGSizeMake(320*7, 200);
    for (int a = 0; a< 7; a++)
    {
        UIImageView *imageview = [[UIImageView alloc] initWithFrame:CGRectMake(320*a, 0, 320, 200)];
        NSString *imagestr = [NSString stringWithFormat:@"%d",a+1];
        imageview.image = [UIImage imageNamed:imagestr];
        [_scrollView addSubview:imageview];
    }

    //设置是否隐藏水平指示条或者竖直指示条
    //Indicator:指示器
    //Vertical:垂直方向
    //    _scrollView.showsVerticalScrollIndicator = NO;
    //    _scrollView.showsHorizontalScrollIndicator = NO;
    //设置指示条的样式
    //    _scrollView.indicatorStyle = UIScrollViewIndicatorStyleBlack;
    //设置scrollView内容的偏移量
    //x: x方向上的偏移量 正值:往左发生偏移 负值:往右偏移
    //y:y方向上的偏移量 正值:往上偏移 负值:往下偏移
    //scrollView.contentOffset = CGPointMake(0, -100);
   
    //设置是否开启回弹的效果
    _scrollView.bounces = NO;
    //设置scrollView是否分页显示
    _scrollView.pagingEnabled = YES;
    _scrollView.delegate = self;
    [self.view addSubview:_scrollView];
}

#pragma mark --- creatpageControl
//页面指示器
-(UIPageControl *)pageControl
{
    _pageControl= [[UIPageControl alloc] initWithFrame:CGRectMake(100, 200, 130, 20)];
    //设置当前选中圆点颜色
    _pageControl.currentPageIndicatorTintColor = [UIColor yellowColor];
    //设置未选中的圆点颜色
    _pageControl.pageIndicatorTintColor = [UIColor blueColor];
    //设置pageControl的圆点个数
    _pageControl .numberOfPages = 7;
    [_pageControl addTarget:self action:@selector(pageMove) forControlEvents:UIControlEventValueChanged];
    return _pageControl;
}

#pragma mark --- pageCOntrol的帮定方法
-(void)pageMove
{
    //随着currentpage的值不断地改变,我们要及时的修改图片的偏移量
    [_scrollView setContentOffset:CGPointMake(_pageControl.currentPage*320, 0) animated:YES];
}

#pragma mark----timer
-(void)ontimer
{
    //currentPage属性设置小圆点的位置
    if (_pageControl.currentPage == 6)
    {
        _speed = -1;
    }
    if (_pageControl.currentPage == 0)
    {
        _speed = 1;
    }
    _pageControl.currentPage = _pageControl.currentPage + _speed;
    //改变偏移量带有动画的方法
    [_scrollView setContentOffset:CGPointMake(_pageControl.currentPage*320, 0) animated:YES];
}

#pragma mark --- UIScrollViewDelegate
//将要开始拖拽
-(void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
    [_timer invalidate];
    _timer = nil;
}

//拖拽结束后减速结束
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
    //手动滑动图片会修改滚动试图偏移量,偏移量改变,让currentPage的值也跟着改变;
    _pageControl.currentPage = _scrollView.contentOffset.x/320;
    _timer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(ontimer) userInfo:nil repeats:YES];
}
@end