UIScrollView自动循环滚动

设置三个ImageView

  - (void)setScrollViewAndPageControl {

      self.scrollView.contentSize = CGSizeMake(viewWidth*3, viewHeight);

      self.pageControl.userInteractionEnabled = NO;

      _firstView = [[UIImageView alloc]init];
      _middleView = [[UIImageView alloc]init];
      _lastView = [[UIImageView alloc]init];

      _firstView.frame = CGRectMake(0, 0, viewWidth, viewHeight);
      _middleView.frame = CGRectMake(viewWidth, 0, viewWidth, viewHeight);
      _lastView.frame = CGRectMake(viewWidth*2, 0, viewWidth, viewHeight);

      [_scrollView addSubview:_firstView];
      [_scrollView addSubview:_middleView];
      [_scrollView addSubview:_lastView];

      _currentPage = 0;

  }

刷新

- (void)reloadData {
    CGFloat contentOffSetX = self.scrollView.contentOffset.x;
    NSInteger imgCount = self.imgArray.count;

    NSInteger leftImgIndex;
    NSInteger rightImgIndex;

    if (contentOffSetX < viewWidth) {
        self.currentPage = (self.currentPage + imgCount - 1) % imgCount;
    } else if (contentOffSetX > viewWidth) {
        self.currentPage = (self.currentPage + 1) % imgCount;
    }

    leftImgIndex = (self.currentPage + imgCount - 1) % imgCount;
    rightImgIndex = (self.currentPage + 1) % imgCount;


    NSString *middelImgStr = self.imgArray[self.currentPage][@"uiIconUrl"];
    NSString *firstImgStr = self.imgArray[leftImgIndex][@"uiIconUrl"];
    NSString *lastImgStr = self.imgArray[rightImgIndex][@"uiIconUrl"];

    [_middleView sd_setImageWithURL:[NSURL URLWithString:middelImgStr] placeholderImage:nil];
    [_firstView sd_setImageWithURL:[NSURL URLWithString:firstImgStr] placeholderImage:nil];
    [_lastView sd_setImageWithURL:[NSURL URLWithString:lastImgStr] placeholderImage:nil];

  }

定时器

  - (void)setRollScrollView {

      self.imgListTimer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0));

      dispatch_source_set_timer(self.imgListTimer, DISPATCH_TIME_NOW, 5.0 * NSEC_PER_SEC, 0.0 * NSEC_PER_SEC);

      dispatch_source_set_event_handler(self.imgListTimer, ^{
    
          [self.scrollView setContentOffset:CGPointMake(viewWidth * 2, 0) animated:YES];
    
          dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.5 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
              [self scrollViewDidEndDecelerating:self.scrollView];
          });
    
      });

  }

至此，大功告成

Ps:有事拍砖