Question

I’m encountering a common TableView data reloading problem. I’ve read many questions on the same subject but the problem was never exactly the same as mine…

I have a navigation based application. In the RootViewController’s viewDidLoad method I make a request in order to get JSON data (articles). When the connection has finished loading I create custom Article objects for each entry. The Article class has an initWithDictionnary method which initializes the attributes of the object and most importantly creates a request to download an image. When the connection has finished loading I set the image attribute of the Article object.
The goal is to initialize the cell.imageView.image property with the downloaded image. At that point, you may have guessed what the problem is about.
Images are downloaded after the cell image is rendered so it stays empty until the cell is reloaded (if it gets out of the screen and then back in for example).
I guess I should call reloadData at a certain time but I don’t know when. Ideally I would call it when all the cells are loaded but it doesn’t seem possible.
I’ve tried a bunch of crazy things like waiting for a cell to load and the try to reload the previous one but it didn’t work.
By reading Q&A out here I learned about Apple’s LazyTableImage sample code but I don’t understand all of it so I’m not sure I should/could use it.

Please ask me if you need more details.

Thanks in advance for any help.

Answer 1

You have to load the images Asynchronously. Keep in mind that your table data should contain a field per row specifying if the image was loaded so that (if true) you can skip loading and just display cached images.

Look at this question first: Load images async