Overriding ASIHTTPRequest's methods

Question

I'm writing app for iPhone using SDK 4.0 that needs to download, re-size and show many images one by one.

I tried to do that with a simple ASIHTTPRequest, but these operations turned out to be very expensive. So I created subclass that inherits from ASIHTTPRequest and I'm trying to override requestFinished. I have though a problem with that. Well.. I need to somehow set that image on my UIImageView. I don't really have any idea how to do that properly.

I tried to create UIImage property in my subclass and put my re-sized image there and then just take it from request. Alas, it causes problems. I'm getting EXC_BAD_ACCESS. I guess that method might be dangerous due to concurrency. Is there any easy and safe way to do that? I thought about parsing that image to NSData and somehow switch it with requests response.

EDIT: JosephH: I did what you wrote there. It helped for small pictures - I mean this which don't need to be resized. So when I added resizing - it lagged again. Here is some code:

#import "BackgroundHTTPRequest.h"

@implementation BackgroundHTTPRequest
@synthesize myimg;

-(UIImage *)imageWithImage:(UIImage*)imagee scaledToSize:(CGSize)newSize
{
    // Create a bitmap context.
    UIGraphicsBeginImageContextWithOptions(newSize, YES, [UIScreen mainScreen].scale);
    [imagee drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
    UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage;

}


- (void)requestFinished{
    NSData *responseData = [self responseData];
    UIImage *tempimg = [UIImage imageWithData:responseData];

    CGFloat ratio = tempimg.size.height / tempimg.size.width;
    CGFloat widthmax = 320;
    CGFloat heightmax = widthmax * ratio;
    myimg = [self imageWithImage:tempimg scaledToSize:CGSizeMake(widthmax, heightmax)];
    [super requestFinished];
}

- (void)dealloc{
    self.myimg = nil;
    [super dealloc];
}
@end

And some code where it happens:

- (IBAction)grabURLInBackground:(NSURL *)url
{
    [self.myrequest setDelegate:nil];
    [self.myrequest cancel];
    [self.myrequest release];


    self.myrequest = [[BackgroundHTTPRequest requestWithURL:url] retain];    

    [myrequest setDelegate:self];
    [myrequest startAsynchronous];

}

- (void)requestFinished:(BackgroundHTTPRequest *)request
{
    // Use when fetching binary data
    if ((NSNull *)self == [NSNull null]){
        [request clearDelegatesAndCancel];
    } else {
        if (self.image)
            self.image.image = myrequest.myimg;
    }
    self.myrequest = nil;
}

Plus adding line

[self.myrequest setCacheStoragePolicy:ASICachePermanentlyCacheStoragePolicy];

Didn't help.

score 0 · Answer 1 · edited May 23 '17 at 11:55

You could try looking at the code I posted in this answer instead:

How? UITableViewCell with UIImageView asynchronously loaded via ASINetworkQueue

Rather than subclassing ASIHTTPRequest, it subclasses UIImageView, which seems to work very well.

You might be able to make it work the other way, but your ASIHTTPRequest would have to retain a reference to the UIImageView... but you've not shown us any code or told us how/where it's crashing, so anything I saw more than that will just be wild speculation.

Overriding ASIHTTPRequest's methods

1 Answers1