UI基于UIScrollView实现图片组手动轮换和自动轮播

#import "RootViewController.h"

@interface RootViewController (){

    UIPageControl * _pageControl;
  
    NSTimer * _timer;
    
    UIScrollView * scrV;
    
    UILabel * label;
}

@end

@implementation RootViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }

    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    [self creatScrollView];
    [self creatPageController];
   [self addTimer];
    // Do any additional setup after loading the view.
}
//加入定时器，在定时器方法中执行换页操作，用于实现自动轮播
-(void)addTimer{

    _timer=[NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(toNextPage) userInfo:nil repeats:YES];
}
-(void)toNextPage{
   
    NSInteger page= _pageControl.currentPage;
    
   //此处以下使用的判断方法，都是基于界面的转换，将最后面补充的第一张图片用第一张图片顶掉，造成视觉的误差，偷梁换柱。
    if (page==0) {
        
        scrV.contentOffset=CGPointMake(0, 0);
            
    }
    page++;

    CGFloat X=page*self.view.frame.size.width;

    
    [UIView animateWithDuration:1 animations:^{
    
    scrV.contentOffset=CGPointMake(X, 0);
    }];

    
    if(page==8){
    
        page=0;
    }
     _pageControl.currentPage=page;
    label.text=[NSString stringWithFormat:@"%d/8",page+1];
}
//定义页面控件，使得页面控件跟随图片转换
-(void)creatPageController{

    _pageControl =[[UIPageControl alloc]initWithFrame:CGRectMake(0, 400, 320, 40)];

    _pageControl.backgroundColor=[UIColor blackColor];
    
    //页面控件透明度
    _pageControl.alpha=0.5;
    
    //定义页面控件显示白点的个数，实际图片为9张，最后一张与第一张一致，因为只实现从左往右，只需在最后添加一张。如需从右往左，即可在第一张前补充一张为最后一张即可，改变初始偏移量就可以实现多个方向转换
    _pageControl.numberOfPages=8;
    
    //虽然实际图片为9张或者10张，但真正要展览的图片只有8张，所以page的页码仍为8，开始展览的第一张一定为0；
    _pageControl.currentPage=0;
    
    [self.view addSubview:_pageControl];
    //定义页码，此处不写无关
    label=[[UILabel alloc]initWithFrame:CGRectMake(270, 460, 50, 20)];
    label.text=@"1/8";
    label.backgroundColor=[UIColor cyanColor];
    label.textAlignment=NSTextAlignmentCenter;
    [self.view addSubview:label];
}
//1??初始化scrollView，加载图片，我使用的动漫00.jpg--动漫08.jpg，所以可以循环创建
-(void)creatScrollView{
     //定义与屏幕大小等高等宽的scrollView
     scrV=[[UIScrollView alloc]initWithFrame:self.view.bounds];

    //加载图片
    for(int i = 0; i < 9; i++){
    
        UIImageView * imageV=[[UIImageView alloc]initWithFrame:CGRectMake(self.view.frame.size.width*i, 0, 320,self.view.frame.size.height)];
       
        [imageV setImage:[UIImage imageNamed:[NSString stringWithFormat:@"动漫%02d.jpg",i+1]]];
    
        [scrV addSubview:imageV];
    
    }
    //定义scrollView的属性
    scrV.contentSize=CGSizeMake(self.view.frame.size.width*9, 0);
    
    //定义初始偏移量 如果第一张前面加了最后一张，那就把初始改为320，0；
    scrV.contentOffset=CGPointMake(0, 0);
    
    //按页面跳转 
    scrV.pagingEnabled=YES;
   
    scrV.showsVerticalScrollIndicator=NO;
    
    //设置代理
    scrV.delegate=self;
    
    [self.view addSubview:scrV];
    
}
#pragma mark **UIScrollViewDelegate**
//在减速结束的方法里，判断页面位置，使页面控件跟随图片变换  此处用于手动轮换。
-(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{
  
    NSLog(@"减速");
    NSInteger page=scrV.contentOffset.x/320;
    
    
    if(page==8){
        
        scrollView.contentOffset=CGPointMake(0, 0);
        page=0;
        
    }
    _pageControl.currentPage=page;

}


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

@end