代码之家 › 专栏 › 技术社区 › Cody Lucas

我在ImageView子类中定义手势识别器,但在ViewController中调用方法会与“Unrecogned selector”崩溃

selector uigesturerecognizer swift ios

Cody Lucas · 技术社区 · 9 年前

我在ImageView子类中定义手势识别器,但在ViewController中调用方法会与“Unrecogned selector”崩溃。如果我在VC中定义手势,手势就可以工作,但我正试图将代码放在自定义视图类中,以减少混乱。

class DetailPhotoImageView: UIImageView {

func setupGestures(){

    let tapped = UITapGestureRecognizer(target: self, action: #selector(TripDetailVC.tapped(_:)))
    tapped.numberOfTapsRequired = 2

    addGestureRecognizer(tapped)

    }
}

然后在VC中,我有这个函数,并调用imageView。设置手势()

func tapped(_ gesture:UIGestureRecognizer) {
    if let tapGesture = gesture as? UITapGestureRecognizer {
        switch tapGesture.numberOfTapsRequired {
        case 2:
            print("Worked")
        default:
            break
        }
    }
}

3 回复 | 直到 9 年前

mmr118 9 年前

王的建议是对的,你也可以用另一种节省空间的方式。将viewController作为参数传递,并将其设置为目标:

class DetailPhotoImageView: UIImageView, UIGestureRecognizerDelegate {

    func setupGestures(_ target: UIViewController) {
        guard let aTarget = target as? MyViewController else { return }

        let tap =  UITapGestureRecognizer(target: aTarget, action: #selector(aTarget.someAction(_:)))
        tap.delegate = self
        tap.numberOfTapsRequired = taps
        addGestureRecognizer(tap)
    }
}

detailPhoto.setupGestures(self)

mmr118 9 年前

为UIImageView制定一个协议,该协议接受手势,并将ViewController设置为代理(将ImageView也作为参数只是一种良好的做法..或常见做法):

protocol DetailPhotoDelegate {  
    func detailPhoto(_ detailPhoto: DetailPhotoImageView, actionFor gesture: UITapGestureRecognizer)
}

在UIImageView子类中添加委托变量,并在点击视图时执行协议函数。此外,请确保您的UIImageView是UIGestureRecognizerDelegate。

class DetailPhotoImageView: UIImageView, UIGestureRecognizerDelegate {

    var delegate: DetailPhotoDelegate?

    func setupGestures() {
        let tap =  UITapGestureRecognizer(target: self, action: #selector(someAction(_:)))
        tap.delegate = self
        tap.numberOfTapsRequired = taps
        addGestureRecognizer(tap)
    }

    func someAction(_ guesture: UITapGestureRecognizer) {
        print("tap - subclass func")
        guard let aDelegate = aDelegate else { assertionFailure(); return }

        delegate.detailPhoto(self, actionFor: gesture)
    }
}

然后将协议添加到ViewController,在执行操作之前的某个地方将其设置为DetailPhotoImageView的委托(我在viewDidLoad()中进行了此操作),然后按照您的意愿实现协议方法:

class ViewController: UIViewController, DetailPhotoDelegate {

    @IBAction weak var detailPhoto: DetailPhotoImageView!

    override func viewDidLoad() {
        super.viewDidLoad()

        detailPhoto.delegate = self
    }

    // Mark: DetailPhotoDelegate
    func detailPhoto(_ detailPhoto: DetailPhotoImageView, actionFor guesture: UITapGestureRecognizer) {

        switch guesture.numberOfTapsRequired {
        case 1: print("1 tap"); return
        case 2: print("2 taps"); return
        default: print("\(guesture.numberOfTapsRequired) taps"); return
        }
    }

Randall Wang 9 年前

我认为目标不应该是自我