Question

In my app I have implemented a method to download a image from a URL and display it in a TableView cell. The code is working fine but I also need to implement two more functions,

1) a UIActivityIndicator to show that the image is being downloaded.
2) Check whether the image is already downloaded. Download only if the cell is empty.

Here is my code.

-(void) downloadImage
{
    NSURL *url = [NSURL URLWithString:@"http://cdn.iphonehacks.com/wp-content/uploads/2012/09/iphone5-front-back.jpg"];
    UIImage *image = [[UIImage alloc] initWithData: [NSData dataWithContentsOfURL:url]];

    [dCellImageView setImage:image];

    [image release];
}

Thanks.

Answer 1

Use [NSData dataWithContentsOfURL:URL options:NSDataReadingMapped error:&error]. It is a synchronized method. So probably start activityIndicator before sending the message, and check error, then stop activityIndicator. What do you mean by ‘cell is empty’? Do you store image in disk or just memory. If former, use NSFileManager to check if file exists.