iOS实现无限循环图片轮播器的封装

@interface JGCirculateSwitchImgView : UIView@property(nonatomic,strong)NSArray *imgUrlArr;@end

typedef NS_ENUM(NSInteger, SwitchDirection){//未成功旋转 SwitchDirectionNone = -1,//向右旋转图片 SwitchDirectionRight = 0,//向左训转图片SwitchDirectionLeft = 1,};

//默认5秒训转图片一次,可以根据需要改变#define WiatForSwitchImgMaxTime 5#import "JGCirculateSwitchImgView.h"#import "UIImageView+WebCache.h"@interface JGCirculateSwitchImgView ()//底部UIScrollView@property(nonatomic,weak)UIScrollView *contentScrollView;//显示页码的UIPageControl控件@property(nonatomic,weak)UIPageControl *pageControlView;//用保存当前UIPageControl控件显示的当前位置@property(nonatomic,assign)NSInteger currentPage;//用于保存当前显示图片在图片urlArr数组中的索引@property(nonatomic,assign)NSInteger currentImgIndex;//UIScrollView上的三个UIImgaView这里通过3个UIImageView实现无限循环图片轮转@property(nonatomic,weak)UIImageView *imgView1;@property(nonatomic,weak)UIImageView *imgView2;@property(nonatomic,weak)UIImageView *imgView3;@property(nonatomic,assign)BOOL isDragImgView;//SwitchDirection类型，用于保存滑动的方向@property(nonatomic,assign)SwitchDirection swDirection;@end

-(id)initWithFrame:(CGRect)frame{  if (self = [super initWithFrame:frame])  {    [self createContentScrollView];    [self createPageControlView];   //默认第一页   _currentPage = 0;   //默认显示第一张图片   _currentImgIndex = 0;   _isDragImgView = NO;   _swDirection = SwitchDirectionNone;  }   return self;}

-(void)createContentScrollView{  UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:self.bounds];  scrollView.delegate = self;  scrollView.showsHorizontalScrollIndicator = NO;  scrollView.shouldGroupAccessibilityChildren = NO;  scrollView.pagingEnabled = YES;  [self addSubview:scrollView];  _contentScrollView = scrollView;}

-(void)createPageControlView{  UIPageControl *pageControlVw = [[UIPageControl alloc] init];  pageControlVw.frame = CGRectMake(0, 0, 80, 20);  pageControlVw.center = CGPointMake(self.center.x, self.bounds.size.height - 20);  pageControlVw.backgroundColor = [UIColor redColor];  _pageControlView.pageIndicatorTintColor = [UIColor yellowColor];  _pageControlView.currentPageIndicatorTintColor = [UIColor purpleColor];  [self addSubview:pageControlVw];  _pageControlView = pageControlVw;}

//value对Count取模,并保证为正值//这里很重要，是实现无限循环的重要的一步，比如现在显示的是第一张图片，_currentImgIndex=0,向左滑动后就显示_currentImgIndex+1张图片，可是_currentImgIndex+1可能回大于_imgUrlArr的数组count，这里取模，其次还要保证为正数，比如，如果向右边滑动是就显示_currentImgIndex-1张图片，_currentImgIndex-1取模也可能为负数，此时加上count保证为正数-(NSInteger)switchToMValue:(NSInteger)value Count:(NSInteger)count{  NSInteger result = value % count;  return result >=0 ? result : result + count;}

-(void)setImgUrlArr:(NSArray *)imgUrlArr{  _imgUrlArr = [imgUrlArr copy];  NSInteger count = imgUrlArr.count;  if (count <= 0 )  {   return;  }  //如果只显示一张图片,那就没有旋转情况  if (count == 1)  {    UIImageView *imgView = [[UIImageView alloc]init];    imgView.frame = CGRectMake(0, 0, self.bounds.size.width, self.bounds.size.height);   [_contentScrollView addSubview:imgView];    _pageControlView.numberOfPages = 1;    _pageControlView.currentPage = 0;   _contentScrollView.contentSize = CGSizeMake(self.bounds.size.width, self.bounds.size.height);   NSURL *imgUrl = [NSURL URLWithString:imgUrlArr[0]];   [imgView sd_setImageWithURL:imgUrl placeholderImage:nil];   return;  }  if (count > 1)  {     //这里只使用3个ImgView轮转多张图片，数量2,3,4,5,6...     for(int i = 0; i < 3 ;i++)     {       UIImageView *imgView = [[UIImageView alloc] init];       imgView.frame = CGRectMake(i * self.bounds.size.width, 0, self.bounds.size.width, self.bounds.size.height);       imgView.layer.masksToBounds = YES;       NSString *urlStr = urlStr = _imgUrlArr[[self switchToValue:i-1 Count:count]];       NSURL *imgUrl = [NSURL URLWithString:urlStr];       [imgView sd_setImageWithURL:imgUrl placeholderImage:nil];       if (i == 0)       {         _imgView1 = imgView;         }        else if (i == 1)       {         _imgView2 = imgView;       }       else if (i == 2)       {         _imgView3 = imgView;        }       [_contentScrollView addSubview:imgView];     }    _pageControlView.numberOfPages = count;     _pageControlView.currentPage = 0;    _contentScrollView.contentSize = CGSizeMake(self.bounds.size.width * 3,  self.bounds.size.height);    _currentImgIndex = 0;    [_contentScrollView setContentOffset:CGPointMake(self.bounds.size.width, 0) animated:NO];   dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{      //循环轮转图片      [self switchImg];   });  }}

-(void)switchImg{   while (1)   {     [NSThread sleepForTimeInterval:WiatForSwitchImgMaxTime];     //如果正在拖拽图片，此次作废       if (_isDragImgView) {        continue;      }      _currentPage = [self switchToValue:_currentPage + 1 Count:_imgUrlArr.count];      dispatch_async(dispatch_get_main_queue(), ^{         _pageControlView.currentPage = _currentPage;         _contentScrollView.contentOffset = CGPointMake(2 * self.bounds.size.width, 0);         [self reSetImgUrlWithDirection:SwitchDirectionLeft];     });   }}

-(void)switchImgByDirection:(SwitchDirection)direction{   if (direction == SwitchDirectionNone) {     return;   }   [self reSetImgUrlWithDirection:direction];   [_contentScrollView setContentOffset:CGPointMake(self.bounds.size.width, 0) animated:NO];}

-(void)reSetImgUrlWithDirection:(SwitchDirection)direction{   if (direction == SwitchDirectionRight) {     [_imgView1 sd_setImageWithURL:[NSURL URLWithString:_imgUrlArr[[self switchToValue:_currentImgIndex - 2 Count:_imgUrlArr.count]]] placeholderImage:nil];     [_imgView2 sd_setImageWithURL:[NSURL URLWithString:_imgUrlArr[[self switchToValue:_currentImgIndex - 1 Count:_imgUrlArr.count]]] placeholderImage:nil];     [_imgView3 sd_setImageWithURL:[NSURL URLWithString:_imgUrlArr[[self switchToValue:_currentImgIndex Count:_imgUrlArr.count]]] placeholderImage:nil];     _currentImgIndex = [self switchToValue:_currentImgIndex - 1 Count:_imgUrlArr.count];   }   else if(direction == SwitchDirectionLeft)   {     [_imgView1 sd_setImageWithURL:[NSURL URLWithString:_imgUrlArr[[self switchToValue:_currentImgIndex Count:_imgUrlArr.count]]] placeholderImage:nil];     [_imgView2 sd_setImageWithURL:[NSURL URLWithString:_imgUrlArr[[self switchToValue:_currentImgIndex + 1 Count:_imgUrlArr.count]]] placeholderImage:nil];     [_imgView3 sd_setImageWithURL:[NSURL URLWithString:_imgUrlArr[[self switchToValue:_currentImgIndex + 2 Count:_imgUrlArr.count]]] placeholderImage:nil];     _currentImgIndex = [self switchToValue:_currentImgIndex + 1 Count:_imgUrlArr.count];   }}

#pragma mark -------------Delegate---------------//记住滑动的方向- (void)scrollViewDidScroll:(UIScrollView *)scrollView{  static float newx = 0;  static float oldx = 0;  newx= scrollView.contentOffset.x ;  if (newx != oldx )  {    if (newx > oldx)    {      _swDirection = SwitchDirectionLeft;    }else if(newx < oldx)   {     _swDirection = SwitchDirectionRight;   }   oldx = newx;  }}- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView{  _isDragImgView = YES;}- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{   //向左旋转   if (_swDirection == SwitchDirectionLeft)   {     _currentPage = [self switchToValue:_currentPage + 1 Count:_imgUrlArr.count];   }//向右旋转   else if (_swDirection == SwitchDirectionRight)   {     _currentPage = [self switchToValue:_currentPage - 1 Count:_imgUrlArr.count];   }   _pageControlView.currentPage = _currentPage;   if (_swDirection != SwitchDirectionNone) {   [self switchImgByDirection:_swDirection];   }  _isDragImgView = NO;}

JGCirculateSwitchImgView *jView = [[JGCirculateSwitchImgView alloc] initWithFrame:CGRectMake(20,100, 280, 250)];NSArray *imgUrlArr = @[@"http://www.blisscake.cn/Upload/Product/Show/Source/ps_1507201119031647109.jpg",@"http://www.blisscake.cn/Upload/Product/Show/Source/ps_1507201116215754685.jpg",@"http://www.blisscake.cn/Upload/Product/Show/Source/ps_1507201115524758041.jpg",@"http://www.blisscake.cn/Upload/Product/Show/Source/ps_1507201114495822068.jpg",@"http://www.blisscake.cn/Upload/Product/Show/Source/ps_1507201107522493367.jpg"];jView.imgUrlArr = imgUrlArr;[self.view addSubview:jView];