如何在集合视图单元格中更改图像视图

Question

I created an imageView in a collection view cell this way:

func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {

    let cell = collectionView.dequeueReusableCellWithReuseIdentifier("Cell", forIndexPath: indexPath)
    let imageView: UIImageView = UIImageView(image: UIImage(named: "image"))
    cell.contentView.addSubview(imageView)

    return cell
}

The collection view has 2 cells, now I need to change the image of the first cell to Batman and the second to Superman , how should I achieve it?

Answer 1

You need compare indexPath.row

func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {

    let cell = collectionView.dequeueReusableCellWithReuseIdentifier("Cell", forIndexPath: indexPath) as! CustomCell

    var image = UIImage(named: "Superman")!
    if indexPath.row == 0 {
        image = UIImage(named: "Batman")!
    }

    cell.imageView.image = image!

    return cell
}

Create your subclass of UICollectionViewCell

class CustomCell: UICollectionViewCell {
    @IBOutlet var imageView : UIImageView!

    override func prepareForReuse() {
        super.prepareForReuse()
        imageView.image = nil
    }
}

And in viewDidLoad method

func viewDidLoad() {
    collectionView.registerClass(CustomCell.self, forCellWithReuseIdentifier: "CustomCell")
}

Answer 2

First of all you shouldn't add subviews in cellForRowAtIndexPath. These code should be in creation of your custom cell.

func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
    let cell = collectionView.dequeueReusableCellWithReuseIdentifier("Cell", forIndexPath: indexPath)

    switch(indexPath.row) {
       case 1: cell.imageView.image = UIImage(named: "batman")!
       case 2: cell.imageView.image = UIImage(named: "superman")!
       default: cell.imageView.image = UIImage(named: "placeholder")!
    }
    return cell
}

Answer 3

You can try this code, I hope this works for you

let cell = collectionView.dequeueReusableCellWithReuseIdentifier("cellIdentifier", forIndexPath: indexPath)

        var imageView: UIImageView? = cell.contentView.viewWithTag(1111) as? UIImageView

        if (imageView != nil) {
            //switch/case, if/else whatever you want to set images accordingly
            imageView!.image = UIImage(named: "image")
        } else {
            imageView = UIImageView()
            imageView!.tag = 1111
            cell.contentView.addSubview(imageView!)
        }

        return cell

Answer 4

Thank you all for the answers! But the above answers are either a little complicated, or not working on my side, so I'm giving my own solution, inspired by @HDT :

func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
    let cell = collectionView.dequeueReusableCellWithReuseIdentifier("Cell", forIndexPath: indexPath)

    if cell.contentView.subviews.count != 0 {

        cell.contentView.subviews[0].removeFromSuperview()

    }

    switch indexPath.row {
    case 0:
        cell.contentView.addSubview(UIImageView(image: frontImage))
    case 1:
        cell.contentView.addSubview(UIImageView(image: backImage))
    default:
        cell.contentView.addSubview(UIImageView(image: UIImage(named: "Image")))
    }

    return cell
}