Question

I’m currently working on an iOS application where you can take an image and upload it to the server.

I have this working fine in the simulators however when testing on the device I get a received memory warning and then it crashes.

There is quite a bit more in my code I’ll just try to show the bits that are relevant to my problem:

I’m trying to send two images taken using the photo picker on the device this is saved to the phone and passed through to a payment screen:

 - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info 
    {
        UIImage *image=[info objectForKey:@"UIImagePickerControllerOriginalImage"];
        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
        NSString *documentsDirectory = [paths objectAtIndex:0];
        NSString* path = [documentsDirectory stringByAppendingPathComponent:[NSString stringWithString: "name.jpg"] ];
        NSData* data = UIImageJPEGRepresentation(image,1.0);
        [data writeToFile:path atomically:YES];
    }

On the payment screen I have this code to send it to the server and the php script sends back the paypal service:

   NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString* path = [documentsDirectory stringByAppendingPathComponent: [NSString stringWithString: @"name.jpg"] ];

    NSData *imageData = UIImageJPEGRepresentation([UIImage imageWithContentsOfFile:path]);


    NSString *urlString = @"http://server.com/payment.php?";
    NSMutableURLRequest *request = [[[NSMutableURLRequest alloc] init] autorelease];
    [request setURL:[NSURL URLWithString:urlString]];
    [request setHTTPMethod:@"POST"];

    NSString *boundary = [NSString stringWithString:@"---------------------------14737809831466499882746641449"];
    NSString *contentType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@", boundary];
    [request addValue:contentType forHTTPHeaderField:@"Content-Type"];

    NSMutableData *body = [NSMutableData data];

    [body appendData:[[NSString stringWithFormat:@"\r\n--%@\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:[[NSString stringWithString:@"Content-Disposition: form-data; name=\"backfile\"; filename=\"back.jpg\"\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:[[NSString stringWithString:@"Content-Type: image/jpeg\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:[NSData dataWithData:imageData]];
    [body appendData:[[NSString stringWithFormat:@"\r\n--%@--\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];

    [webView loadRequest:request];


    [self.view addSubview:webView];
    [request setHTTPBody:body];

Sorry if this isn’t too clear please let me know. It sends the images to the server but the app will crash in the process. I have tried resizing the images however i need them at the best quality possible. If I send scaled down images using:

    UIGraphicsBeginImageContext( frontSize );
    [frontimg drawInRect:CGRectMake(0,0,242,444)];
    UIImage* realfrontImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    NSData *frontImageData = UIImageJPEGRepresentation(image, 1.0);

It works however the image quality is 72PPI when I need it up around 300.

Any help would be much appreciated.

Answer 1

It’s an unusual use of the webview to do a post. It’s possible that the webview (or something else essential) is getting released on memory warning. Can you replace it with this and see if it helps?

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

[NSURLConnection request queue:queue completionHandler:^(NSURLResponse *response, NSData *data, NSError *error)
{
    NSHTTPURLResponse* httpResponse = (NSHTTPURLResponse*)response;
    NSLog(@"got response %d, data = %@, error = %@", [httpResponse statusCode], data, error);
}];