更新2013年04月02日11:46:36：修改了用 [imageView setImageWithURLRequest:[NSURLRequestrequestWithURL:[NSURLURLWithString:@""]] placeholderImage:[UIImageimageNamed:@"loader.jpg"] success:^(NSURLRequest *request, NSHTTPURLResponse *response, UIImage *image) { } failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error) { }];图片不能缓存的问题
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ASI好久没更新，于是今天试了下AFNetWorking，调用图片请求方法很方便
[self.imageViewsetImageWithURL:[NSURLURLWithString:@"http://best50.cn:8080/update/10/food/72.jpg"] placeholderImage:[UIImageimageNamed:@"placeholder.png"]];
但发现个问题，程序重新启动后，图片还要重新请求，原来AFN用的是内存缓存图片机制，这能提高程序效率，但我们有时候，图片的本地缓存也是很重要的，于是，对AFN下UIImageView+AFNetworking.m文件的代码进行了修改，欢迎大家进行指正，修改和添加的方法如下：
1 - (void)setImageWithURLRequest:(NSURLRequest *)urlRequest 2 placeholderImage:(UIImage *)placeholderImage 3 success:(void (^)(NSURLRequest *request, NSHTTPURLResponse *response, UIImage *image))success 4 failure:(void (^)(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error))failure 5 { 6 [self cancelImageRequestOperation]; 7 8 9 UIImage *cachedImage = [[[self class] af_sharedImageCache] cachedImageForRequest:urlRequest]; 10 if (cachedImage) { 11 12 self.image = cachedImage; 13 self.af_imageRequestOperation = nil; 14 15 if (success) { 16 success(nil, nil, cachedImage); 17 } 18 } else { 19 NSString *urlString = [[urlRequest URL] absoluteString]; 20 NSData *data = [self loadImageData:[self pathInCacheDirectory:@"WendaleCache"] imageName:[urlString md5]]; 21 if (data) { 22 self.image = [UIImage imageWithData:data]; 23 self.af_imageRequestOperation = nil; 24 25 if (success) { 26 success(nil, nil, self.image); 27 } 28 return; 29 } 30 31 self.image = placeholderImage; 32 33 AFImageRequestOperation *requestOperation = [[AFImageRequestOperation alloc] initWithRequest:urlRequest]; 34 [requestOperation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) { 35 if ([[urlRequest URL] isEqual:[[self.af_imageRequestOperation request] URL]]) { 36 if (success) { 37 success(operation.request, operation.response, responseObject); 38 }else if (responseObject) {
39 self.image = responseObject;}
40 //图片本地缓存 41 if ([self createDirInCache:@"WendaleCache"]) { 42 NSString *imageType = @"jpg"; 43 //从url中获取图片类型 44 NSMutableArray *arr = (NSMutableArray *)[urlString componentsSeparatedByString:@"."]; 45 if (arr) { 46 imageType = [arr objectAtIndex:arr.count-1]; 47 } 48 [self saveImageToCacheDir:[self pathInCacheDirectory:@"WendaleCache"] image: responseObject imageName:[urlString md5] imageType:imageType]; 49 } 50 51 52 53 54 self.af_imageRequestOperation = nil; 55 } 56 57 [[[self class] af_sharedImageCache] cacheImage:responseObject forRequest:urlRequest]; 58 59 } failure:^(AFHTTPRequestOperation *operation, NSError *error) { 60 if ([[urlRequest URL] isEqual:[[self.af_imageRequestOperation request] URL]]) { 61 if (failure) { 62 failure(operation.request, operation.response, error); 63 } 64 65 self.af_imageRequestOperation = nil; 66 } 67 }]; 68 69 self.af_imageRequestOperation = requestOperation; 70 71 [[[self class] af_sharedImageRequestOperationQueue] addOperation:self.af_imageRequestOperation]; 72 } 73 } 74 75 -(NSString* )pathInCacheDirectory:(NSString *)fileName 76 { 77 NSArray *cachePaths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES); 78 NSString *cachePath = [cachePaths objectAtIndex:0]; 79 return [cachePath stringByAppendingPathComponent:fileName]; 80 } 81 //创建缓存文件夹 82 -(BOOL) createDirInCache:(NSString *)dirName 83 { 84 NSString *imageDir = [self pathInCacheDirectory:dirName]; 85 BOOL isDir = NO; 86 NSFileManager *fileManager = [NSFileManager defaultManager]; 87 BOOL existed = [fileManager fileExistsAtPath:imageDir isDirectory:&isDir]; 88 BOOL isCreated = NO; 89 if ( !(isDir == YES && existed == YES) ) 90 { 91 isCreated = [fileManager createDirectoryAtPath:imageDir withIntermediateDirectories:YES attributes:nil error:nil]; 92 } 93 if (existed) { 94 isCreated = YES; 95 } 96 return isCreated; 97 } 98 99 // 删除图片缓存 100 - (BOOL) deleteDirInCache:(NSString *)dirName 101 { 102 NSString *imageDir = [self pathInCacheDirectory:dirName]; 103 BOOL isDir = NO; 104 NSFileManager *fileManager = [NSFileManager defaultManager]; 105 BOOL existed = [fileManager fileExistsAtPath:imageDir isDirectory:&isDir]; 106 bool isDeleted = false; 107 if ( isDir == YES && existed == YES ) 108 { 109 isDeleted = [fileManager removeItemAtPath:imageDir error:nil]; 110 } 111 112 return isDeleted; 113 } 114 115 // 图片本地缓存 116 - (BOOL) saveImageToCacheDir:(NSString *)directoryPath image:(UIImage *)image imageName:(NSString *)imageName imageType:(NSString *)imageType 117 { 118 BOOL isDir = NO; 119 NSFileManager *fileManager = [NSFileManager defaultManager]; 120 BOOL existed = [fileManager fileExistsAtPath:directoryPath isDirectory:&isDir]; 121 bool isSaved = false; 122 if ( isDir == YES && existed == YES ) 123 { 124 if ([[imageType lowercaseString] isEqualToString:@"png"]) 125 { 126 isSaved = [UIImagePNGRepresentation(image) writeToFile:[directoryPath stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.%@", imageName, @"png"]] options:NSAtomicWrite error:nil]; 127 } 128 else if ([[imageType lowercaseString] isEqualToString:@"jpg"] || [[imageType lowercaseString] isEqualToString:@"jpeg"]) 129 { 130 isSaved = [UIImageJPEGRepresentation(image, 1.0) writeToFile:[directoryPath stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.%@", imageName, @"jpg"]] options:NSAtomicWrite error:nil]; 131 } 132 else 133 { 134 NSLog(@"Image Save Failed\nExtension: (%@) is not recognized, use (PNG/JPG)", imageType); 135 } 136 } 137 return isSaved; 138 } 139 // 获取缓存图片 140 -(NSData*) loadImageData:(NSString *)directoryPath imageName:( NSString *)imageName 141 { 142 BOOL isDir = NO; 143 NSFileManager *fileManager = [NSFileManager defaultManager]; 144 BOOL dirExisted = [fileManager fileExistsAtPath:directoryPath isDirectory:&isDir]; 145 if ( isDir == YES && dirExisted == YES ) 146 { 147 NSString *imagePath = [directoryPath stringByAppendingString : imageName]; 148 BOOL fileExisted = [fileManager fileExistsAtPath:imagePath]; 149 if (!fileExisted) { 150 return NULL; 151 } 152 NSData *imageData = [NSData dataWithContentsOfFile : imagePath]; 153 return imageData; 154 } 155 else 156 { 157 return NULL; 158 } 159 }