如何将URL中的图像加载到UITableViewCell的UIImageView中？

Question

尝试提取从JSON图像和显示器上的tableview细胞，而且在转换到数据变得nill

dispatch_async(dispatch_get_global_queue(0,0), ^{ 
    NSData * data = [[NSData alloc] initWithContentsOfURL: [NSURL URLWithString: @"http://myurl/mypic.jpg"]]; 
    if (data == nil) 
     return; 
    dispatch_async(dispatch_get_main_queue(), ^{ 
     // WARNING: is the cell still using the same data by this point?? 
     cell.imageView.image = [UIImage imageWithData: data]; 
    }); 
}); 

为NSData的*数据其始终表示零，即使我硬编码等

NSData *data = [NSData dataWithContentsOfURL:[NSURL URLWithString:@"http://upload.wikimedia.org/wikipedia/commons/thumb/6/6b/American_Beaver.jpg/220px-American_Beaver.jpg"]]; 

它是在数据变量中显示nil

我是否做错了什么？任何其他最好的方式相同？

Answer 1

您可以使用SDWebImage为图像执行延迟加载。

#import <SDWebImage/UIImageView+WebCache.h> 

[cell.imageView sd_setImageWithURL:[NSURL URLWithString:IMAGE_URL] 
      placeholderImage:[UIImage imageNamed:@"placeholder.png"]]; 

Answer 2

此代码正在工作，您可能从json得到了错误的图片网址。

dispatch_async(dispatch_get_global_queue(0,0), ^{ 
      NSData * data = [[NSData alloc] initWithContentsOfURL: [NSURL URLWithString: @"http://upload.wikimedia.org/wikipedia/commons/thumb/6/6b/American_Beaver.jpg/220px-American_Beaver.jpg"]]; 
      if (data == nil) 
       return; 
      dispatch_async(dispatch_get_main_queue(), ^{ 
       // WARNING: is the cell still using the same data by this point?? 
       UIImage *image = [UIImage imageWithData:data]; 
       NSLog(@"%@",image); 

      }); 
     }); 

Answer 3

#import "SDWebImage/UIImageView+WebCache.h" 

[cell.imageView sd_setImageWithURL:[NSURL URLWithString:@"http://www.freeiconspng.com/uploads/flower-png-22.png"] 
     placeholderImage:[UIImage imageNamed:@"placeholder.png"]]; 

You can download class of SDWebImage from this link