将UITapGestureRecognizer添加到XIB

Question

I've created a custom XIB extending from UITableViewHeaderFooterView and attempting to add a gesture recognizer. Only problem is attempting to add the recognizer via interface builder results in the object being added to the top level hierarchy and the following error causing my app to crash:

Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'invalid nib registered for identifier (AccordionHeader) - nib must contain exactly one top level object which must be a UITableViewHeaderFooterView instance'

To the best of my knowledge there's no "viewDidLoad" equivalent available or I would just be adding the recognizer programmatically. Is there another way to do this?

Answer 1

You are right, the recognizer must not be added to the XIB on top level.

My solution as follows:

class SettingsUserAvatarHeader: UITableViewHeaderFooterView {

    // Set as a variable, as it will be re-created on cell re-use
    var tapGestureRecognizer = UITapGestureRecognizer()

    // This will be called every time the cell moves off screen and returns 
    override func prepareForReuse() {
        super.prepareForReuse()

        // Needs to be done manually.
        tapGestureRecognizer = UITapGestureRecognizer()
        avatarImageView.gestureRecognizers = [ tapGestureRecognizer ]
    }

    // This will be needed for the first display
    override func didMoveToSuperview() {
        super.didMoveToSuperview()

        avatarImageView.gestureRecognizers = [ tapGestureRecognizer ]
    }
}

With this, you can listen to the taps directly. I'm using RxSwift:

First, add a extension for the tap:

extension Reactive where Base: SettingsUserAvatarHeader {

    var avatarTap: ControlEvent<UITapGestureRecognizer> {
        return self.base.tapGestureRecognizer.rx.event.asControlEvent()
    }

}

And in your controller/delegate etc:

class Consumer: UITableViewDelegate {

    var avatarTapDisposable: Disposable?

    override func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
        let cell = tableView.dequeueReusableHeaderFooterView(withIdentifier: "userAvatarView")
        let view = cell as! SettingsUserAvatarHeader

        avatarTapDisposable =
                view.rx
                    .avatarTap
                    .subscribe(onNext: { (tap) in
                        // Here your code for the tap
                    })

        return cell
    }
}

Answer 2

Try This

Step 1:- Register XIB file

func regXib(){
 self.tblList.register(UINib(nibName: "YourCellName", bundle: nil), forHeaderFooterViewReuseIdentifier: "YourCellNameIdentifierName")
}

Step:- 2 viewForHeaderInSection Method

func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
        let cell = tableView.dequeueReusableHeaderFooterView(withIdentifier: "YourCellNameIdentifierName") as! YourCellName
        let recognizer = UITapGestureRecognizer(target: self, action: #selector(self.expand))
        cell.layer.backgroundColor = UIColor.white.cgColor
        cell.addGestureRecognizer(recognizer)
        cell.tag = section
        return cell
    }

Step 3:- Tap Gesture Action

@objc func expand(sender:UITapGestureRecognizer){
   let tag = (sender.view?.tag)!
   // Tap Action Code Here 
}