Question

i m loading an image from an url and displaying it in imageView .i m using NSBLockOperation to load the image and it runs in the background and it takes time to load the image in imageview..is there any way to increase the performance so that it takes less time..below is the code.

NSOperationQueue *queue=[[NSOperationQueue alloc]init];
NSBlockOperation *operation=[NSBlockOperation blockOperationWithBlock:^{

    [activityIndicator startAnimating];
    NSString *imagefile = [banner1 objectAtIndex:0]; 
    NSURL *url1=[NSURL URLWithString:imagefile];
    NSData *data = [NSData dataWithContentsOfURL:url1];
    UIImage *ui=[[UIImage alloc]initWithData:data];
    bigbanner.image=ui;
    [activityIndicator stopAnimating];
    bigbanner.alpha=0.0;

}];
[operation setCompletionBlock:^{
    [UIView animateWithDuration:3.0 animations:^{bigbanner.alpha=2.0;}
                     completion:^(BOOL finished){}];
}];

[queue addOperation:operation];

Answer 1

I would guess that your limiting factor is the image download.
Loading an image and placing it on screen happens quite fast on iOS.

Other than changing your three second fade-in to a shorter interval, I think you’re stuck.

You might try doing the download using [NSURLRequest], but I doubt you’ll notice a major difference.

I’d say your options are (ranked in order of speed):

1. cache or include images in your bundle (don’t download).
2. make your images smaller
3. increase the speed of your server

Also: a side note, and hopefully someone else passing through can answer this… is setting the image property of a UIImageView from a non-main-thread safe to do? I was under the impression that everything that happened to the UI was supposed to happen on the main thread.