容易的图片无限轮播器

  1 #import "ViewController.h"  2 #define kDeviceWidth [UIScreen mainScreen].bounds.size.width  3 #define kDeviceHeight [UIScreen mainScreen].bounds.size.height  4 #define   Kpage 3  5 @interface ViewController ()<UIScrollViewDelegate>  6   7 @property(nonatomic,strong)UIPageControl *pageCtrl;  8 @property (nonatomic,weak) UIScrollView *scrollView;  9 @property (nonatomic,weak) UIImageView *currentImageView; // 当前imageView 10 @property (nonatomic,weak) UIImageView *nextImageView; // 下一个imageView 11 @property (nonatomic,weak) UIImageView *preImageView; //上一个imageView 12 @property (nonatomic,assign) BOOL isDragging; // 是否正在拖动 13 @property (nonatomic,strong)NSTimer *timer; 14 @end 15  16 @implementation ViewController 17  18 - (void)viewDidLoad { 19     [super viewDidLoad]; 20     UIScrollView *scrollView =[[UIScrollView alloc] init]; 21     scrollView.frame = CGRectMake(0, 0, kDeviceWidth, kDeviceHeight); 22     [self.view addSubview:scrollView]; 23     self.scrollView = scrollView; 24     [self.scrollView setContentSize:CGSizeMake(kDeviceWidth * 3, kDeviceWidth)]; 25     //  设置隐藏横向条 26     self.scrollView.showsHorizontalScrollIndicator = NO; 27     //  设置自动分页 28     self.scrollView.pagingEnabled = YES; 29     //  设置代理 30     self.scrollView.delegate = self; 31     //  设置当前点 32     self.scrollView.contentOffset = CGPointMake(kDeviceWidth, 0); 33     //  设置是否有边界 34     self.scrollView.bounces = NO; 35     //  初始化当前视图 36     UIImageView *currentImageView =[[UIImageView alloc] init]; 37     currentImageView.image = [UIImage imageNamed:@"bg_01"]; 38     [self.scrollView addSubview:currentImageView]; 39     self.currentImageView = currentImageView; 40     self.currentImageView.frame = CGRectMake(kDeviceWidth, 0, kDeviceWidth, kDeviceHeight); 41     self.currentImageView.contentMode = UIViewContentModeScaleAspectFill; 42     //  初始化下一个视图 43     UIImageView *nextImageView = [[UIImageView alloc] init]; 44     nextImageView.image = [UIImage imageNamed:@"bg_02"]; 45     [self.scrollView addSubview:nextImageView]; 46     self.nextImageView = nextImageView; 47     self.nextImageView.frame = CGRectMake(kDeviceWidth * 2, 0, kDeviceWidth, kDeviceHeight); 48     self.nextImageView.contentMode = UIViewContentModeScaleAspectFill; 49     //  初始化上一个视图 50     UIImageView *preImageView =[[UIImageView alloc] init]; 51     preImageView.image = [UIImage imageNamed:@"bg_03"]; 52     preImageView.frame = CGRectMake(0, 0, kDeviceWidth, kDeviceHeight); 53     [self.scrollView addSubview:preImageView]; 54     self.preImageView = preImageView; 55     self.preImageView.contentMode =UIViewContentModeScaleAspectFill; 56  57     //  设置时钟动画 定时器 58  59     self.timer = [NSTimer scheduledTimerWithTimeInterval:2 target:self selector:@selector(update:) userInfo:nil repeats:YES]; 60     //  将定时器添加到主线程 61     [[NSRunLoop mainRunLoop] addTimer:self.timer forMode:NSRunLoopCommonModes]; 62  63 } 64     // 分页 65 -(UIPageControl *)pageCtrl{ 66     if (_pageCtrl == nil) { 67          68         //分页控件 69         _pageCtrl = [[UIPageControl alloc]init]; 70         _pageCtrl.numberOfPages = Kpage; 71          72         CGSize size = [_pageCtrl sizeForNumberOfPages:Kpage]; 73         _pageCtrl.bounds = CGRectMake(0, 0, size.width, size.height); 74         _pageCtrl.center = CGPointMake(self.view.center.x, CGRectGetMaxY(self.scrollView.frame) - 20); 75         _pageCtrl.pageIndicatorTintColor = [UIColor redColor]; 76         _pageCtrl.currentPageIndicatorTintColor = [UIColor greenColor]; 77          78         [self.view addSubview:_pageCtrl]; 79          80          81     } 82     return _pageCtrl; 83 } 84  85  86 -(void)updateTimer{ 87     //修改页号 88     int page = (self.pageCtrl.currentPage + 1 ) % Kpage; 89     self.pageCtrl.currentPage = page; 90    91 } 92  93  94 - (void)update:(NSTimer *)timer{ 95     //定时移动 96      97     if (_isDragging == YES) { 98          99         return ;100     }101     CGPoint offSet = self.scrollView.contentOffset;102     offSet.x +=offSet.x;103     104     [self updateTimer];105     106     [self.scrollView setContentOffset:offSet animated:YES];107     if (offSet.x >= kDeviceWidth *2) {108         offSet.x = kDeviceWidth;109     }110    111 }112 #pragma mark - UIScrollViewDelegate113 - (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView114 {115     _isDragging = YES;116 }117     //  停止滚动118 - (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView119 {120     _isDragging = NO;121 122 }123 124     // 开始拖动125 - (void) scrollViewDidScroll:(UIScrollView *)scrollView{126     static int i =1; //   当前展示的是第几张图片127     float offset = self.scrollView.contentOffset.x;128     if (self.nextImageView.image == nil || self.preImageView.image == nil) {129     //  加载下一个视图130     NSString *imageName1 = [NSString stringWithFormat:@"bg_0%d",i == Kpage ? 1:i +1];131     _nextImageView.image = [UIImage imageNamed:imageName1];132     // 加载上一个视图133     NSString *imageName2 = [NSString stringWithFormat:@"bg_0%d",i==1 ? Kpage :i-1];134     _preImageView.image = [UIImage imageNamed:imageName2];135      136     }137     if(offset ==0){138         _currentImageView.image = _preImageView.image;139         scrollView.contentOffset = CGPointMake(scrollView.bounds.size.width, 0);140         _preImageView.image = nil;141         if (i == 1) {142         i =Kpage;143         } else{144         i-=1;145         }146 147     }148     if (offset == scrollView.bounds.size.width * 2) {149         _currentImageView.image = _nextImageView.image;150         scrollView.contentOffset = CGPointMake(scrollView.bounds.size.width, 0);151         _nextImageView.image = nil;152         if (i == Kpage) {153         i = 1 ;154         }else{155         i +=1 ;156         }157       158     }159    160 }161 162 163 @end