一个简单的测试应用程序中的JMImageCache与EXC_BAD_ACCESS崩溃 [英] JMImageCache in a simple test app crashes with EXC_BAD_ACCESS

问题描述

在Xcode 5.0.2中

1. 我创建并更改 Jake Marsh（JMImageCache的作者） ）注意：

   
   

   JMImageCache有目的地使用NSString对象而不是NSURL来简化和减少[NSURL URLWithString：@... 比特到处都是。如果您发现任何奇怪的EXC_BAD_ACCESS异常，请注意以下事项，确保您传入NSString而不是NSURL。

   
   

   但是（作为一个iOS编程新手）我不明白，Marsh先生究竟是什么意思 - 因为他的文件 UIImageView + JMImageCache.m 将公共方法的第一个参数声明为 NSURL ：

      - （void）setImageWithURL：（NSURL *）url占位符：（UIImage *）占位符图像{
    [self setImageWithURL：url key： nil placeholder：placeholderImage]; 
   } 
     

   笔记可能已过时，我该如何修复我的应用程序？

   解决方案

   这是JMImageCache中的一个错误。 setImageWithURL：key ：占位符：completionBlock： 调用自身，耗尽堆栈。

   
   
   

   要解决此问题，请调用较长的形式方法：

     [_ imageView setImageWithURL：[NSURL URLWithString：kAvatar] 
    key：nil 
   占位符：[ UIImage imageNamed：@male.png] 
    completionBlock：nil 
    failureBlock：nil]; 
     

   或者，使用旧版本的库（例如 0.4.0 ）。看起来这个bug是在 1af09be78a 中引入的。

   
   

   In Xcode 5.0.2

   1. I create a blank single view app for iPhone,
   2. then add a "male.png" image to the project,
   3. drag a UIImageView to the storyboard

   4. and finally add the following code to the viewDidLoad:

      _imageView.image = [UIImage imageNamed:@"male.png"];

   This works well:

   Then I add the 4 files from JMImageCache project and change the ViewController.m to:

   #import "ViewController.h"
   #import "JMImageCache.h"
   
   static NSString* const kAvatar = @"http://gravatar.com/avatar/55b3816622d935e50098bb44c17663bc.png";
   
   @interface ViewController ()
   
   @end
   
   @implementation ViewController
   
   - (void)viewDidLoad
   {
       [super viewDidLoad];
   
       [_imageView setImageWithURL:[NSURL URLWithString:kAvatar]
               placeholder:[UIImage imageNamed:@"male.png"]];
   }
   
   @end
   

   Unfortunately, this results in app crash with the error message Thread 1: EXC_BAD_ACCESS:

   At his webpage Jake Marsh (the author of JMImageCache) notes:

   JMImageCache purposefully uses NSString objects instead of NSURL's to make things easier and cut down on [NSURL URLWithString:@"..."] bits everywhere. Just something to notice in case you see any strange EXC_BAD_ACCESS exceptions, make sure you're passing in NSString's and not NSURL's.

   But (as an iOS programming newbie) I don't understand, what exactly does Mr. Marsh mean - since his file UIImageView+JMImageCache.m declares the 1st argument for the public method as NSURL:

   - (void) setImageWithURL:(NSURL *)url placeholder:(UIImage *)placeholderImage {
       [self setImageWithURL:url key:nil placeholder:placeholderImage];
   }
   

   Is the note maybe outdated and how could I fix my app?

   解决方案

   That's a bug in JMImageCache. setImageWithURL:key:placeholder:completionBlock: calls itself, exhausting the stack.

   To work around the bug, call the longer form of the method:

   [_imageView setImageWithURL:[NSURL URLWithString:kAvatar]
       key:nil
       placeholder:[UIImage imageNamed:@"male.png"]
       completionBlock:nil
       failureBlock:nil];
   

   Or, use an older version of the library (e.g. 0.4.0). Looks like the bug was introduced in 1af09be78a.

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