Question

Hi I have this code to download images from the server and then to show them in table view with some text (if there is no image I want to show the text anyway):

//download part

NSMutableString *photourl=[[NSMutableString alloc] initWithString:url_image];
    [photourl appendString:[dic objectForKey:@"photo"]];

    @try{

      //add to mutable array
    [photoSmallImageData addObject:[NSData dataWithContentsOfURL:[NSURL URLWithString:photourl]]];
    }
    @catch (id Exception) {
        [photoSmallImageData addObject:[NSData dataWithContentsOfURL:[NSURL URLWithString:url_image]]];

    }

//part of table view code

NSData *imageData = [photoSmallImageData objectAtIndex:indexPath.row];

    @try {

        cell.imageView.image = [UIImage imageWithData:imageData];
    }
    @catch (NSException *exception) {
      cell.imageView.image = [UIImage imageNamed:@"icon72.png"];
    }

1. It works but the thing is sometimes there is no image so I would like to replace it with some icon but since we can’t add nil to array i juste add some part of my link there and then even if the link doesn’t work for image data it doesn’t call the catch method. I don’t know if I could some how replace the url with local url but I don’t know how. Also I can’t skip the step because then the images will not correspond to the text next to it.

2.The images are all of diferent sizes and I would like them to have standard look and be centered is there a way to do that and at which point of the code? Thank you very much

EDIT I have found the method:
dataWithContentsOfURL:options:error:
http://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Classes/NSData_Class/Reference/Reference.html
but I don’t know how to use it

Answer 1

Why don’t you create the images when the image data is downloaded and keep them in the array? Also, you are right to be after the dataWithContentsOfURL:options:error: method. Given that you keep the image names in the dic dictionary, the code would look like this:

NSMutableString *photourl=[[NSMutableString alloc] initWithString:url_image];
[photourl appendString:[dic objectForKey:@"photo"]];

//try to create the image
NSError* err = nil;
UIImage* img = nil;
NSData* tempData = [NSData dataWithContentsOfURL:[NSURL URLWithString:photourl] options:NSDataReadingMappedIfSafe error:&err];
if (!err) {
    // image data loaded, create image
    img = [UIImage imageWithData:tempData];
} else {
    // image data could not be loaded, display error
    NSLog(@"%@", err);
    // put the default image in the array
    img = [UIImage imageNamed:@"icon72.png"];
}
[photoSmallImage addObject:img];

And then in the table view delegate:

cell.imageView.image = [photoSmallImage objectAtIndex:indexPath.row];

As for the second part of your question, you may want to have a look at the contentMode property of UIView class. The default is scale to fill. By manipulating this property on the cell.imageView, you can achieve the effect that you desire.