Question

在子视图上创建的UIImageView上的长按手势不会触发其目标。虽然，我已经启用了用户交互，但没有结果。子视图是否以某种方式干扰并避免触发，或者我完全错过了什么？我对社区提前表示感谢。

private func createShieldView() -> Void {


    self.baseView.addSubview(self.imageForShield)
    self.imageForShield.translatesAutoresizingMaskIntoConstraints = false
    //Constraints functions created in an extension
    self.imageForShield.horizontalLeft(toItem: self.alarmBaseView, constant: 0)
    self.imageForShield.horizontalRight(toItem: self.alarmBaseView, constant: 0)
    self.imageForShield.topConstraints(toItem: self.labelForInstruction, constant: 5, toBottomOf: true)
    self.imageForShield.heightConstriants(constant: 250)

    let imageFile = UIImage(named: "stateInactive")
    self.imageForShield.image = imageFile
    self.imageForShield.contentMode = UIViewContentMode.scaleAspectFit
    self.imageForShield.tag = tagsAssignedToViews.shieldView.rawValue

    let longPressEvent = UILongPressGestureRecognizer(target: self, action: #selector(ViewController._selectorLongPressEvent(longPressGestuer:)))
    longPressEvent.minimumPressDuration = 2.0
    self.imageForShield.addGestureRecognizer(longPressEvent)

    self.imageForShield.isUserInteractionEnabled = true
}

//In ViewController.swift
public func _selectorLongPressEvent(longPressGestuer: UILongPressGestureRecognizer) -> Void {
    if longPressGestuer.state == UIGestureRecognizerState.began {
        print("Long press event triggered")
    }

}

Answer 1

我测试你的代码（除了约束），如下所示，它工作，它打印信息，试图找到问题：

import UIKit

class ViewController: UIViewController {

    lazy var baseView:UIView = {

        let view:UIView = UIView.init()
        view.frame = CGRect.init(x: 0, y: 0, width: self.view.bounds.size.width, height: self.view.bounds.size.height)
        return view
    }()

    lazy var imageForShield:UIImageView = {

        let imageView:UIImageView = UIImageView.init(frame: CGRect.init(x: 0, y: 0, width: 330, height: 330))
        imageView.backgroundColor = UIColor.red
        return imageView
    }()

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.

        self.createShieldView()
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    private func createShieldView() -> Void {

        self.view.addSubview(self.baseView)
        self.baseView.addSubview(self.imageForShield)
        self.imageForShield.translatesAutoresizingMaskIntoConstraints = false
        //Constraints functions created in an extension
        /*
         self.imageForShield.horizontalLeft(toItem: self.alarmBaseView, constant: 0)
        self.imageForShield.horizontalRight(toItem: self.alarmBaseView, constant: 0)
        self.imageForShield.topConstraints(toItem: self.labelForInstruction, constant: 5, toBottomOf: true)
        self.imageForShield.heightConstriants(constant: 250)
         */

        let imageFile = UIImage(named: "stateInactive")
        self.imageForShield.image = imageFile
        self.imageForShield.contentMode = UIViewContentMode.scaleAspectFit
        //self.imageForShield.tag = tagsAssignedToViews.shieldView.rawValue

        let longPressEvent = UILongPressGestureRecognizer(target: self, action: #selector(ViewController._selectorLongPressEvent(longPressGestuer:)))
        longPressEvent.minimumPressDuration = 2.0
        self.imageForShield.addGestureRecognizer(longPressEvent)

        self.imageForShield.isUserInteractionEnabled = true
    }

    //In ViewController.swift
    public func _selectorLongPressEvent(longPressGestuer: UILongPressGestureRecognizer) -> Void {
        if longPressGestuer.state == UIGestureRecognizerState.began {
            print("Long press event triggered")
        }

    }

}

将我的代码复制到一个新项目，它可以工作。

Swift 3长按手势不在子视图上工作

1 个答案: