gooberboobbutt gooberboobbutt - 1 year ago 64
Swift Question

Is there a way to not redownload images everytime a user opens the app?

I'm working on a tableView that shows images and it is re-downloading the images every time the view loads. Is there a way to cache the images so it only downloads the images once? (Cache the images)

Answer Source

You can do this:

In your tableViewDelegate create a Cache object

var myCache = NSCache()

Then in the rowAtIndexPath

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    if let row = tableView.dequeueReusableCellWithIdentifier("MyCell") as? MyCell{

        //Get the item
        let item = items[indexPath.row]

        //You need to cancel previous requests and reset the image to avoid render errors caused by the reusable row
        //here you should also cancel any previous requests made to avoid downloading an image that the user won't see because he scrolled 
        cell.img.image = nil

        //Search for the image in the cache
        var img:UIImage?
        img = myCache.objectForKey(item.image_url) as? UIImage

        row.configureCell( item: item,img:img)

        return row

        return MyCell()

And finally in the cell

func configureCell(item:Item,image:UIImage?){
    self.item = item

    if image != nil{
        //The image exist so you assign it to your UIImageView
        img.image = image
        //Create the request to download the image