轮播图 定时滚动

图片轮播器 在很多应用软件中都有应用 ，需要制作 无限滚动的 ，下面贴上自己写的小Demo， 能实现相关的功能。

Ps： 没有用到pageControl ，只是图片自动无限滚动 ，没有任何的 处理 。

#import "ViewController.h"

 

@interface ViewController : UIViewController <</span>UIScrollViewDelegate>

@property (nonatomic,weak) UIScrollView *scrollView;

@property (nonatomic,weak) UIImageView *currentImageView;   // 当前imageView

@property (nonatomic,weak) UIImageView *nextImageView;      // 下一个imageView

@property (nonatomic,weak) UIImageView *preImageView;       //上一个imageView

@property (nonatomic,assign) BOOL isDragging;               //是否正在拖动

@property (nonatomic,strong)NSTimer *timer;                 //设置动画

@end

@implementation ViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    // Do any additional setup after loading the view, typically from a nib.

    UIScrollView *scrollView =[[UIScrollView alloc] init];

    CGFloat width = self.view.frame.size.width;

    CGFloat height = self.view.frame.size.height;

    scrollView.frame = CGRectMake(0, 0, width, height);

    [self.view addSubview:scrollView];

    self.scrollView = scrollView;

    [self.scrollView setContentSize:CGSizeMake(width * 3, height)];

    //  设置隐藏横向条

    self.scrollView.showsHorizontalScrollIndicator = NO;

    //  设置自动分页

    self.scrollView.pagingEnabled = YES;

    //  设置代理

    self.scrollView.delegate = self;

    //  设置当前点

    self.scrollView.contentOffset = CGPointMake(width, 0);

    //  设置是否有边界

    self.scrollView.bounces = NO;

    //  初始化当前视图

    UIImageView *currentImageView =[[UIImageView alloc] init];

    currentImageView.image = [UIImage imageNamed:@"1.jpg"];

    [self.scrollView addSubview:currentImageView];

    self.currentImageView = currentImageView;

    self.currentImageView.frame = CGRectMake(width, 0, width, height);

    self.currentImageView.contentMode = UIViewContentModeScaleAspectFill;

    //  初始化下一个视图

    UIImageView *nextImageView = [[UIImageView alloc] init];

    nextImageView.image = [UIImage imageNamed:@"2.jpg"];

    [self.scrollView addSubview:nextImageView];

    self.nextImageView = nextImageView;

    self.nextImageView.frame = CGRectMake(width * 2, 0, width, height);

    self.nextImageView.contentMode = UIViewContentModeScaleAspectFill;

    //  初始化上一个视图

    UIImageView *preImageView =[[UIImageView alloc] init];

    preImageView.image = [UIImage imageNamed:@"6.jpg"];

    preImageView.frame = CGRectMake(0, 0, width, height);

    [self.scrollView addSubview:preImageView];

    self.preImageView = preImageView;

    self.preImageView.contentMode =UIViewContentModeScaleAspectFill;

    

    //  设置时钟动画 定时器

    self.timer = [NSTimer scheduledTimerWithTimeInterval:1.0f target:selfselector:@selector(update:) userInfo:nil repeats:YES];

    //  将定时器添加到主线程

    [[NSRunLoop mainRunLoop] addTimer:self.timer forMode:NSRunLoopCommonModes];

    

}

- (void)update:(NSTimer *)timer{

    //定时移动

    

    if (_isDragging == YES) {

        return ;

    }

    CGPoint offSet = self.scrollView.contentOffset;

   offSet.x +=offSet.x;

   [self.scrollView setContentOffset:offSet animated:YES];

 

    if (offSet.x >= self.view.frame.size.width *2) {

        offSet.x = self.view.frame.size.width;

    }

    

    

}

#pragma mark - UIScrollViewDelegate

- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView

{

    _isDragging = YES;

}

//  停止滚动

- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView

{

    _isDragging = NO;

    step = 0;

}

// 开始拖动

- (void) scrollViewDidScroll:(UIScrollView *)scrollView{

    static int i =1; //   当前展示的是第几张图片

    float offset = self.scrollView.contentOffset.x;

    if (self.nextImageView.image == nil || self.preImageView.image == nil) {

        //  加载下一个视图

        NSString *imageName1 = [NSString stringWithFormat:@"%d.jpg",i == KOUNT ? 1:i +1];

        _nextImageView.image = [UIImage imageNamed:imageName1];

        // 加载上一个视图

        NSString *imageName2 = [NSString stringWithFormat:@"%d.jpg",i==1 ? KOUNT :i-1];

        _preImageView.image = [UIImage imageNamed:imageName2];

    }

    if(offset ==0){

        _currentImageView.image = _preImageView.image;

        scrollView.contentOffset = CGPointMake(scrollView.bounds.size.width, 0);

        _preImageView.image = nil;

        if (i == 1) {

            i =KOUNT;

        } else{

            i-=1;

        }

    }

    if (offset == scrollView.bounds.size.width * 2) {

        _currentImageView.image = _nextImageView.image;

        scrollView.contentOffset = CGPointMake(scrollView.bounds.size.width, 0);

        _nextImageView.image = nil;

        if (i == KOUNT) {

            i  =1 ;

        }else{

            i +=1 ;

        }

    }

    

}

- (void)didReceiveMemoryWarning {

    [super didReceiveMemoryWarning];

    // Dispose of any resources that can be recreated.

}

@end