Change image on select within tableview cell - Swift

Question

I am trying to change an image within a cell when it is selected. Here is what I have in my view controller:

func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {

let cell = self.tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath) as! CustomTableViewCell

        cell.bgImage.image = UIImage(named: "second_image")

}

This is where I set the image:

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {

let cell = self.tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath) as! CustomTableViewCell

cell.bgImage.image = UIImage(named: "first_image")

}

When I select the cell, the image does not update. How do I get this to work?

Answer 1

func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
let cell = tableView.cellForRowAtIndexPath(indexPath) as! CustomTableViewCell
cell.bgImage.image = UIImage(named: "second_image")}

For Swift 3+:

func tableView(tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let cell = tableView.cellForRow(at: indexPath) as! CustomTableViewCell
cell.bgImage.image = UIImage(named: "second_image")}

Answer 2

The issue is probably that you are calling dequeueReusableCellWithIdentifier. Try using cellForRowAtIndexPath instead (documentation about it here). This will give you a reference to the current cell, rather than a reference to a new reusable cell.

So, according to your code above:

let cell = self.tableView.cellForRowAtIndexPath(indexPath) as! CustomTableViewCell

This typecast is critical because cellForRowAtIndexPath returns UITableViewCell, which will not have the bgImage member.

Also, make sure that you have a member called bgImage that is a UIImageView in your CustomTableViewCell class by adding @IBOutlet strong var bgImage: UIImageView!, and that said IBOutlet is connected in your storyboard/xib.

Answer 3

Can't you simply use the .hightlightedimage value for the imageView? I'm doing the following in my cellForRowAt func:

cell.imageView?.image = UIImage(named: "\(indexPath.row).png")
cell.imageView?.highlightedImage = UIImage(named: "\(indexPath.row)g.png")

And I've just named the necessary images "0.png" and "0g.png" etc to make sure the image and highlighted image match up. Of course, that's a small static array, if you were using coreData with a larger array you could simply hold the imageName and the hightlightedImageName in the data set and pull the info from there.