Swift: 为什么点按手势识别器每次都不起作用？

Question

我有一个奇怪的问题。我有一个基本的点击手势识别器添加到我的子视图中，但它只在它喜欢的时候工作。有时它适用于第二次点击，有时适用于第三次甚至更多次点击。但是当我将 print("whatever") 添加到手势识别器调用的函数时，它总是在我第一次单击子视图时起作用。

我该如何解决这个问题？

在这两个例子中出现同样的问题：

子视图：

let getGiftGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(self.getGift))
self.continueButton.addGestureRecognizer(getGiftGestureRecognizer)

        DispatchQueue.main.async {
            self.coverAnyUIElement(element: self.successView)
            let gift = SCNNode()
             gift.geometry = SCNBox(width: 1, height: 1, length: 1, chamferRadius: 0)

             //nahodne vygenerovat geometry, nebo barvu
             let ownedGeometries = UserDefaults.standard.array(forKey: "ownedGeometries")
             let ownedColors = UserDefaults.standard.array(forKey: "ownedColors")
             let notOwnedGeometriesCount = geometriesCount - ownedGeometries!.count
             let notOwnedColorsCount = colorsCount - ownedColors!.count

             if notOwnedGeometriesCount == 0{
                 //mam vsechny geometrie
                 //vygeneruju barvu

             }else if notOwnedColorsCount == 0{
                 //mam vsechny barvy
                 //vygeneruju geometrii
             }else if(notOwnedGeometriesCount == 0 && notOwnedColorsCount == 0){
                 //mam uplne vsechno

             }else{
                 //vygeneruj cokoliv
                 let random = Int.random(in: 0...10)
                 if random <= 3{

                     //vygeneruj geometrii
                 }else{
                     //vygeneruj barvu
                 }
             }
             print(self.generateColor())
             print(self.generateGeometry())



            self.chest.opacity = 1
             self.chest.position.y = -1.8
             self.world.addChildNode(self.chest)
             let viko = self.chest.childNode(withName: "viko", recursively: false)
             self.chest.addChildNode(gift)

            print("VLAKNO1: \(Thread.isMainThread)")
             viko?.runAction(SCNAction.rotateBy(x: 0, y: 0, z: -90/(180/CGFloat.pi), duration: 1),completionHandler: {
                print("VLAKNO2: \(Thread.isMainThread)")

                    let pohyb = SCNAction.move(by: SCNVector3(0,4,0), duration: 1)
                    gift.runAction(pohyb,completionHandler: {
                       print("VLAKNO3: \(Thread.isMainThread)")

                            self.showConfirmGiftButton()


                    })


             })
        }
    }

按钮：

confirmGiftButton.addTarget(self, action: #selector(acceptedGift), for: .touchUpInside)

@objc func acceptedGift(){
        DispatchQueue.main.async {
            UIButton.animate(withDuration: 0.2, animations: {
                self.confirmGiftButton.alpha = 0.9
            }) { (_) in
                UIButton.animate(withDuration: 0.2, animations: {
                    self.confirmGiftButton.alpha = 1
                }) { (_) in

                    //print("VLAKNO1: \(Thread.isMainThread)")
                    self.chest.runAction(SCNAction.fadeOut(duration: 0.5),completionHandler: {
                       // print("Vlakno: \(Thread.isMainThread)")
                        self.chest.removeFromParentNode()
                        self.moveToMenu()
                    })
                    //print("VLAKNO2: \(Thread.isMainThread)")
                    self.coverAnyUIElement(element: self.confirmGiftButton)
                }
            }
        }
    }

Answer 1

所以我从这两种方法中删除了 DispatchQueue.main.async 并尝试了几次，这似乎是问题所在，因为现在子视图手势识别器和按钮目标都可以在第一次点击时正确工作。

我认为这是因为当我点击按钮时，主线程已经被使用所以它以某种方式跳过了方法。并在第二次或更多次点击中工作，因为那时它已经是空的。

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