如何获取AFNetworking的UIImageView类别存储的缓存图像？ [英] How do I get cached image stored by AFNetworking's UIImageView category?

问题描述

我在我的应用中使用了 AFNetworking 中的以下类别 UIImageView + AFNetworking.h

有一次，我想获取一张已经在缓存中的图像。

因此，我深入研究上述类别，在其中找到了我认为可以帮助您的以下代码。

以下是其中的代码段：

  @implementation AFImageCache 
 
-（UIImage *）cachedImageForRequest：（NSURLRequest *）request {
开关（[request cachePolicy]）{
 case NSURLRequestReloadIgnoringCacheData：
 case NSURLRequestReloadIgnoringLocalAndRemoteCacheData：
 return nil; 
默认值：
休息时间； 
} 
 
 return [self objectForKey：AFImageCacheKeyFromURLRequest（request）]; 
} 
 
-（void）cacheImage：（UIImage *）image 
 forRequest：（NSURLRequest *）request 
 {
 if（image&& ; request）{
 [self setObject：image forKey：AFImageCacheKeyFromURLRequest（request）]; 
} 
} 
 
 @end 
  

如果您要我添加此内容的网络版本，它已经

我不确定如何解决这些警告并从缓存中获取图像？还是其他更合适的方法？

解决方案

我假设您导入了UIImageView + AFNetworking.h标头。

如果要访问缓存的图像。您应该有一个NSURLRequest对象。然后是这样的：

  UIImage * image = [[UIImageView sharedImageCache] cachedImageForRequest：request]; 
  

完成！

I'm using following category UIImageView+AFNetworking.h from AFNetworking in my app, its working fine, its caching photos for me and loads images smoothly.

At one point, I want to get an image which is already there in my cache.

So I dig up into above category class where I found following code, which I think – can be helpful.

Here's the snippet from it:

@implementation AFImageCache

- (UIImage *)cachedImageForRequest:(NSURLRequest *)request {
    switch ([request cachePolicy]) {
        case NSURLRequestReloadIgnoringCacheData:
        case NSURLRequestReloadIgnoringLocalAndRemoteCacheData:
            return nil;
        default:
            break;
    }

    return [self objectForKey:AFImageCacheKeyFromURLRequest(request)];
}

- (void)cacheImage:(UIImage *)image
        forRequest:(NSURLRequest *)request
{
    if (image && request) {
        [self setObject:image forKey:AFImageCacheKeyFromURLRequest(request)];
    }
}

@end

If you want me to add web version of this, it's already here.

I think, - (UIImage *)cachedImageForRequest:(NSURLRequest *)request is the method which can return me my cached image.

But I'm not sure, how can I use it?

If I know Objective-C a bit, it's a kinda a "protocol"?

What I have tried so far is to use it like a protocol in one of my view controller. Like this:

#import <UIKit/UIKit.h>

@interface MyViewController : UIViewController<AFImageCache>

@end

But then it is giving me following warnings:

I'm not sure how to resolve those warnings and get the image from cache? Or any other more appropriate way?

解决方案

I assume you import UIImageView+AFNetworking.h header.

If you want to access to the cached image. You should have a NSURLRequest object. Then it is like this:

UIImage *image = [[UIImageView sharedImageCache] cachedImageForRequest:request];

Done!

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