UIScrollView 的嵌套以及加载图片太多的问题

Question

最近我遇到一个问题，在ios开发中做一个类似于手机相册的功能，具体内容如下：
1.有一个200/300百张的图片数组放在沙河中，做一个左右手动的轮播图，每张图都要可以实现缩放问题。
2.差不多已经实现了，就是利用scrollView的嵌套，由于加载是一张张的，导致首次在滚动的过程中会出现空白。
主要代码如下：
//结束减速

• (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView { if (scrollView == self.sv) { int index = scrollView.contentOffset.x / scrollView.frame.size.width; NSString *filePath = [fileDestination stringByAppendingString:@"/images"]; NSString *imagePath =[NSString stringWithFormat:@"/%@/%@",filePath,self.imageArr[index]]; UIImageView *imv = [self.imageViews objectAtIndex:index]; imv.image = [UIImage imageWithContentsOfFile:imagePath]; } }

• (UIScrollView *)sv {
  if(_sv == nil) {
  _scrollViews = [[NSMutableArray alloc] init];
  _imageViews = [[NSMutableArray alloc]init];

  _sv = [[UIScrollView alloc] initWithFrame:(CGRectMake(0, 64, KScrollViewWidth,  KScrollViewHeight - 128))];
  _sv.contentSize = CGSizeMake(KScrollViewWidth * self.imageArr.count, KScrollViewHeight - 128);
  _sv.delegate = self;
  CGFloat x = self.index * KScrollViewWidth;
  _sv.contentOffset = CGPointMake(x, 0);
  _sv.pagingEnabled = YES;
  //_sv是横向滚动的股东栏
  [self.view addSubview:_sv];
  for (int i = 0; i < self.imageArr.count; i ++) {
      UIScrollView * scrollView = [[UIScrollView alloc] initWithFrame:(CGRectMake(KScrollViewWidth * i, 0, KScrollViewWidth, KScrollViewHeight - 128))];
      scrollView.minimumZoomScale = 1;
      scrollView.maximumZoomScale = 10;
      [_sv addSubview:scrollView];
      scrollView.delegate = self;
      UIImageView *iv = [[UIImageView alloc] initWithFrame:(CGRectMake(0, 0, KScrollViewWidth, KScrollViewHeight - 128))];
      NSString *filePath = [fileDestination stringByAppendingString:@"/images"];
       [iv setImage:[UIImage imageNamed:@"789.png"]];
      if (self.index == i) {
          NSString *imagePath =[NSString stringWithFormat:@"/%@/%@",filePath,self.imageArr[i]];
          iv.image = [UIImage imageWithContentsOfFile:imagePath];
      }
  
      self.icon = iv;
      iv.contentMode = UIViewContentModeScaleAspectFit;
      [scrollView addSubview:iv];
      iv.tag = 1000;
      [self.imageViews addObject:iv];
      [self.scrollViews addObject:scrollView];
  }
  

  }
  return _sv;
  }
  在这里我添加了一张默认的图片，但是在使用的时候还是很别扭，哪位大神帮帮忙呀？

Answer 1

http://blog.csdn.net/ericzkx/article/details/45225263