copy UIImageView that pulls from setImageWithURL - ios

Question

before i had been pulling the same image twice from my server by using, which worked fine but i need to cut down network usage
NSString *friendAvatar = [NSString stringWithFormat:#"%#%#%#", #"http://www.mydomain.com/images/users/", myWords[0], #".jpg"];
[imageFile setImageWithURL:[NSURL URLWithString:friendAvatar]];
[bgImageFile setImageWithURL:[NSURL URLWithString:friendAvatar]]; //this is a zoomed in version of the friends photo
now i am using this way to attempt to pul the image of the UIImageView that already pulled the photo, that way i dont have to be pulling the same photo twice...
NSString *friendAvatar = [NSString stringWithFormat:#"%#%#%#", #"http://www.mydomain.com/images/users/", myWords[0], #".jpg"];
[imageFile setImageWithURL:[NSURL URLWithString:friendAvatar]];
[bgImageFile setImage:imageFile.image];
when trying to use my new method. nothing happens. no error in the debugger, the background image just simply is blank.

Answer 1

Based on your comment I discovered that because you are using AFNetworking when you call
[imageFile setImageWithURL:[NSURL URLWithString:friendAvatar]];
it is being executed on a background thread, but the next line
[bgImageFile setImage:imageFile.image];
is not a AFNetworking call so it is being executed before the previous line has completed and thus there is no imageFile.image to use...
So, yes, my previous answer requires you to do the async code yourself, or you could wait for the image to load before setting bgImageFile.image (Which might be done with KVO???)

Answer 2

Try creating a UIImage first then set UIImageView.image to the created UIImage...
UIImage *avatarImage = [[UIImage alloc] initWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:friendAvatar]]];
[imageFile setImage:avatarImage];
[bgImageFile setImage:avatarImage];
And a better way would be...
dispatch_queue_t myQueue = dispatch_queue_create("com.myProgram.myQueue", NULL);
dispatch_async(myQueue, ^{
UIImage *avatarImage = [[UIImage alloc] initWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:friendAvatar]]];
dispatch_async(dispatch_get_main_queue(), ^{
[imageFile setImage:avatarImage];
[bgImageFile setImage:avatarImage];
});
});
This will load the file from the internet on a background thread and then update the ImageViews on the main thread when the image is done loading. The benefit is that your app won't freeze up during downloading.
I hope that helps