在UI表格视图单元格中单击获取图像

Question

i tried to add gesture recognizer in my UIImageView

 let rc = UITapGestureRecognizer(target: self, action: "foo:")
 rc.numberOfTapsRequired = 1
 rc.numberOfTouchesRequired = 1
 cell.bar.tag = indexPath.row
 cell.bar.addGestureRecognizer(rc)

but didn't call my foo function

func foo(sender: UIImageView! ) {
    self.performSegueWithIdentifier("VC", sender: sender)
}

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject!) {
    if segue.identifier == "VC" {
        let vc = segue.destinationViewController as! VC
        vc.item = items[sender.tag]
    }
}

Answer 1

So, as I mentioned before your problem is UIImageView by default has property userInteractionEnabled set to false . You can change this in you storyboard, or add line cell.bar.userInteractionEnabled = true .

Next your problem is in your foo: method implementation: you specify sender as UIImageView! , but it should be UITapGestureRecognizer . This is why it crashes - it cannot be UIImageView , so when it unwraps ( ! ) it is nil .

Solution: change your foo method declaration to foo(recognizer: UITapGestureRecognizer) . If you need access your imageView inside this method you can use code below:

if let imageView = recognizer.view as? UIImageView {
  ...
}

or with new guard keyword (Swift 2.0)

guard let imageView = recognizer.view as? UIImageView
else { return }
...

Answer 2

You can change

foo(recognizer: UITapGestureRecognizer) {

}