UIImageView Takes Time To Load Image

Question

I have some problem I wanted to download image from internet from particular link Downloading this image take place in other class which is singlton class name moreAppInternet.m

My moreAppInterNet.m file is as follow

//finishedImgDling is bool

//mutableData is NSMutableData

//urlConnection is NSURLConnection

//appimage is UIImage

//imageUrl is NSString Containing Link

+(id)sharedManager {

static moreAppInterNet *sharedMyManager = nil;

@synchronized(self) {

    if (sharedMyManager == nil)

        sharedMyManager = [[self alloc] init];
}

return sharedMyManager;

}

-(void)downloadImageFromUrl {
finishedImgDling = NO;

[self.mutableData setLength:0];

self.urlConnection = [NSURLConnection connectionWithRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:self.imageUrl]] delegate:self];


while(!finishedImgDling) {
    [[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]];
}   

}

-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {

if (connection == self.urlConnection)
{

    NSLog(@"imageDling");
}

}

-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {

if (connection == self.urlConnection)
{

    if (self.mutableData == nil)
    {
        self.mutableData = [NSMutableData data];
    }

    [self.mutableData appendData:data];
}

}

-(void)connectionDidFinishLoading:(NSURLConnection *)connection {

if (connection == self.urlConnection)
{
    NSLog(@"image Downloaded");

    finishedImgDling = YES;

    [self setUrlConnection:nil];

    [self storeImage];
}

}

-(void)storeImage {

[self setAppimage:nil];

self.appimage = [UIImage imageWithData:self.mutableData];

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];     
NSFileManager *fileManager = [NSFileManager defaultManager];

NSString *path =[documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"appImage.png"]];

[fileManager createFileAtPath:path contents:UIImagePNGRepresentation(self.appimage) attributes:nil];

 NSLog(@"downloading and storing complete");

}

and my other ViewController is as follow from where I call that function

-(void)viewDidLoad {

[moreAppInterNet sharedManager];

[self downloadImage];

}

-(void)downloadImage {

 NSInvocationOperation *operation = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(download_Image_from_other_class) object:nil];

NSOperationQueue *que = [[NSOperationQueue alloc] init];

[que addObserver:self forKeyPath:@"operations" options:0 context:NULL];

[que addOperation:operation];

[operation release];

self.dlingQue = que;

[que release];

}

-(void)download_Image_from_other_class {

[[moreAppInterNet sharedManager] downloadImageFromUrl];

}

-(void) observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {

if ([keyPath isEqualToString:@"operations"] && object == self.dlingQue)
{

    if ([self.dlingQue operationCount] == 0)
    {

        self.imgView = [[moreAppInterNet sharedManager] appimage];

        //it takes lots of time to display image in UIImageView
        //Even though Above line get executed
    }
}
else {

    [super observeValueForKeyPath:keyPath ofObject:object
                           change:change context:context];
}

}

The Problem is self.imgView takes Lots of time to load the image approx 5sec even though its downloaded completely

Can anyone help me or tell me What am I doing wrong

Answer 1

我用于联网的库是AFNetworking

Answer 2

I think your code downloads the image again when you request it.

You need to check if you have the file in downloadImageFromUrl .

Probably, you need more robust library to handle file downloading.