Delayed loading of images on cards

Question

I'm specifically looking at doing this in a CardScrollAdapter, but it would be also good to know in the LiveCard situation when publishing a card to the timeline. Is there a way to use volley or any other networking library to load images using the generic Card class?

Answer 1

While you can't use Volley's NetworkImageView class directly with a Card (because the Card manages its own layout), you should be able to use other features in Volley to handle delay-loading your images.

At a high-level, you could use an approach like this:

1. When you create your Card, have it initially use a placeholder image if the desired image isn't already available (cached somewhere). Keep track of the instance of the Card somewhere (in the adapter, for example).
2. Enqueue a request to load the image.
3. Once the image has been retrieved, write the image out to your application's cache directory and add it to the card using a file: URL.
4. Call Card.toView() again to regenerate the card's views and update your UI as needed.