insert images to the device's cache - iOS - iphone

Question

is there a way to insert images, that are downloaded from the web, to the devices cache?
in my application, there's a few views that contains images. at every tableView there's 25-30 images.
the problem is that the images are loaded when scrolled, and the result is at scrolling the image takes 2-3 seconds to reload... doesn't look good :)
at the moment, i'm using NSURLRequest at each cell.
NSURL* url = [NSURL URLWithString:article.articleImage];
NSURLRequest* request = [NSURLRequest requestWithURL:url];
[NSURLConnection sendAsynchronousRequest:request
queue:[NSOperationQueue mainQueue]
completionHandler:^(NSURLResponse * response,
NSData * data,
NSError * error)
{
if (!error)
{
UIImage* image = [[UIImage alloc] initWithData:data];
MainImg.image = image;
article.articleImg=image;
}
}];
I've tried to use multi thread, but the launch of the application takes too long.
ideas?

Answer 1

Hi you need UIImageView+AFNetworking.h category download and use AFNetworking u are sorted
use its - (void)setImageWithURL:(NSURL *)url method works like charm

Answer 2

You can use NSURLCache for this purpose. Yesterday I've worked with this, and I make class:
#interface MyURLCache : NSURLCache
#property (nonatomic, assign) NSTimeInterval timeAvaiable;
#end
#implementation MyURLCache
- (id)initWithMemoryCapacity:(NSUInteger)memoryCapacity diskCapacity:(NSUInteger)diskCapacity diskPath:(NSString *)path
{
self = [super initWithMemoryCapacity:memoryCapacity diskCapacity:diskCapacity diskPath:path];
if(self){
_timeAvaiable = 5*60;//5 мин
}
return self;
}
- (id)init
{
self = [super init];
if(self){
_timeAvaiable = 5*60;
}
return self;
}
+ (NSCachedURLResponse*)addInfoDataToCachedResponce:(NSCachedURLResponse*)cachedResponse
{
NSMutableDictionary* newUserInfo = [#{#"LastUpdate" : #([[NSDate date] timeIntervalSince1970])} mutableCopy];
if([cachedResponse userInfo])
newUserInfo[#"UserInfo"] = [cachedResponse userInfo];
return [[NSCachedURLResponse alloc] initWithResponse:[cachedResponse response]
data:[cachedResponse data]
userInfo:newUserInfo
storagePolicy:[cachedResponse storagePolicy]];
}
+ (NSCachedURLResponse*)removeInfoDataFromCachedResponce:(NSCachedURLResponse*)cachedResponse
{
return [[NSCachedURLResponse alloc] initWithResponse:[cachedResponse response]
data:[cachedResponse data]
userInfo:[cachedResponse userInfo][#"UserInfo"]
storagePolicy:[cachedResponse storagePolicy]];
}
- (NSCachedURLResponse *)cachedResponseForRequest:(NSURLRequest *)request
{
NSCachedURLResponse* result = [super cachedResponseForRequest:request];
NSDate* lastUpdate = [NSDate dateWithTimeIntervalSince1970:[result.userInfo[#"LastUpdate"] doubleValue]];
BOOL expired = fabs([lastUpdate timeIntervalSinceNow]) > _timeAvaiable;
return expired? nil : [[self class] removeInfoDataFromCachedResponce:result];
}
- (void)storeCachedResponse:(NSCachedURLResponse *)cachedResponse forRequest:(NSURLRequest *)request
{
[super storeCachedResponse:[[self class] addInfoDataToCachedResponce:cachedResponse] forRequest:request];
}
#end
And just enable cache when app loaded:
MyURLCache *URLCache = [[MyURLCache alloc] initWithMemoryCapacity:4 * 1024 * 1024
diskCapacity:20 * 1024 * 1024
diskPath:[SDURLCache defaultCachePath]];
[NSURLCache setSharedURLCache:URLCache];
For each request need set cachePolicy to NSURLRequestReturnCacheDataElseLoad.
Or just use AFNetworking :)
- (void)setImageWithURLRequest:(NSURLRequest *)urlRequest
placeholderImage:(UIImage *)placeholderImage
success:(void (^)(NSURLRequest *request, NSHTTPURLResponse *response, UIImage *image))success
failure:(void (^)(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error))failure;

Answer 3

In all my apps I'm using this framework. Very simple to use
https://github.com/rs/SDWebImage
Code example
[cell.imageView setImageWithURL:[NSURL URLWithString:#"http://www.domain.com/path/to/image.jpg"]
placeholderImage:[UIImage imageNamed:#"placeholder.png"]
];

Answer 4

Use This:
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory,NSUserDomainMask, YES);
NSString *savedImagePath = [NSString stringWithFormat:#"%#/%#",[paths objectAtIndex:0],[article.articleImage lastPathComponent]];
UIImage *image = [UIImage imageNamed:savedImagePath];
if(!image)
{
NSURL* url = [NSURL URLWithString:article.articleImage];
NSURLRequest* request = [NSURLRequest requestWithURL:url];
[NSURLConnection sendAsynchronousRequest:request
queue:[NSOperationQueue mainQueue]
completionHandler:^(NSURLResponse * response,
NSData * data,
NSError * error)
{
if (!error)
{
[data writeToFile:savedImagePath atomically:NO];
UIImage* image = [UIImage imageNamed:savedImagePath];
MainImg.image = image;
article.articleImg=image;
}
}];
}
else
{
MainImg.image = image;
article.articleImg=image;
}