scrollView ——自动轮播并且设置图片底部小圆点

#import "ScrollViewController.h"
#import "Global.h"


#define ScrollViewHeight (SCREENHEIGHT - 100)

@interface ScrollViewController ()

@property (nonatomic, strong) UIScrollView *scrollView;
@property (nonatomic, strong) UILabel *label;
@property (nonatomic, strong) UIPageControl *pageControl;
@property (nonatomic, strong) NSTimer *timer;

@end

@implementation ScrollViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    
    
    
    [self initView];
}

- (void)initView
{
    
    //设置滚动视图的主体
    _scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, SCREENWIDTH, ScrollViewHeight)];
    
    _scrollView.pagingEnabled = YES;
    _scrollView.bounces = NO;
    
    _scrollView.delegate = self;
    
    for (int i = 1; i < 5; ++i)
    {
        
        UIImageView *imageView = [[UIImageView alloc] initWithFrame: CGRectMake(0, (i - 1) * ScrollViewHeight, SCREENWIDTH, ScrollViewHeight)];
        
        imageView.image = [UIImage imageNamed:[NSString stringWithFormat:@"%d.jpg", i]];
        [_scrollView addSubview:imageView];
    }
    
    //设置第五张图片和第一张图片相同
    
    UIImageView *imageView = [[UIImageView alloc] initWithFrame: CGRectMake(0, 4 * ScrollViewHeight, SCREENWIDTH, ScrollViewHeight)];
    
    imageView.image = [UIImage imageNamed:@"1.jpg"];
    [_scrollView addSubview:imageView];
    
    _scrollView.contentSize = CGSizeMake(SCREENWIDTH, ScrollViewHeight * 5);
    
    [self.view addSubview:_scrollView];
    
    //设置时钟
    _timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(changeView) userInfo:nil repeats:YES];
    
    //设置底部文字
    _label = [[UILabel alloc] initWithFrame:CGRectMake(SCREENWIDTH / 2 - 50, ScrollViewHeight, SCREENWIDTH, 50)];
    _label.textColor = [UIColor whiteColor];
    _label.text = @"这是第1页";
    [self.view addSubview:_label];
    
    //设置视图上的小圆点
    _pageControl = [[UIPageControl alloc] initWithFrame:CGRectMake(0, ScrollViewHeight - 50, SCREENWIDTH, 30)];
    _pageControl.numberOfPages = 4;
    _pageControl.currentPage = 0;
    
    [_pageControl addTarget:self action:@selector(pageTurn:) forControlEvents:UIControlEventValueChanged];
    
    [self.view addSubview:_pageControl];

}

//设置时钟调用的方法
- (void)changeView
{
    float resultPiontY = 0.0;
    //这里获取的信息是未翻页前的信息。
    
    //当前的点不在最后一页的时候，每次正常翻页，当是最后一页的时候，把最后一页变为第一页（小圆点当前页数设置为1，当前点设置为0.0）
    //注意：当前的计算点是下一页的点，当前计算的页数是下一页的页数
    int i = 1;
    if (_scrollView.contentOffset.y < 3 * ScrollViewHeight)
    {
        i = _scrollView.contentOffset.y / (SCREENHEIGHT - 100) + 1;
    }
    else if (_scrollView.contentOffset.y == 3 *ScrollViewHeight)
    {
        i = 0;
    }
    else
    {
        _scrollView.contentOffset = CGPointMake(0, 0);
    }
    
    
    _label.text = [NSString stringWithFormat:@"这是第%d页", i + 1];
    
    _pageControl.currentPage = i;
    
    resultPiontY = _scrollView.contentOffset.y + ScrollViewHeight;
    
    [_scrollView setContentOffset:CGPointMake(0, resultPiontY) animated:YES];
}

//设置小圆点点击方法
- (void)pageTurn:(UIPageControl *)sender
{
    
    [_scrollView setContentOffset:CGPointMake(0, sender.currentPage * _scrollView.frame.size.height) animated:YES];
}

//当开始拖拽的时候停止时钟
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
    [_timer setFireDate:[NSDate distantFuture]];
}

//当结束拖拽时执行的方法，
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate
{
    _label.text = [NSString stringWithFormat:@"这是第%d页", (int)(scrollView.contentOffset.y / (SCREENHEIGHT - 100)) + 1];
    
    
}
//当结束滚当时执行的方法，变更页数，并且在5秒后开始时钟
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
    //这里获取的信息是已经翻过页的信息
    int i = 0;
    if (_scrollView.contentOffset.y < 4 * ScrollViewHeight)
    {
        i = scrollView.contentOffset.y / (SCREENHEIGHT - 100);
    }
    else
    {
        _scrollView.contentOffset = CGPointMake(0, 0);
        i = 0;
    }
    
    _label.text = [NSString stringWithFormat:@"这是第%d页", i + 1];
    
    _pageControl.currentPage = i;
    
    [_timer setFireDate:[NSDate dateWithTimeInterval:5.0 sinceDate:[NSDate date]]];
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

/*
#pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    // Get the new view controller using [segue destinationViewController].
    // Pass the selected object to the new view controller.
}
*/

@end