Question

我正在尝试在我的应用中实现一个Pan Gesture，我需要访问.Ended状态中的初始点。

这是代码。

func handleTestViewTap (panRecognizer: UIPanGestureRecognizer){

    var locationOfBeganTap: CGPoint?

    if panRecognizer.state == UIGestureRecognizerState.Began {           
        locationOfBeganTap = panRecognizer.locationInView(view)
        print("locationOfBeganTap in BEGAN State -> .\(locationOfBeganTap)")

    } else if panRecognizer.state == UIGestureRecognizerState.Ended {            
        print("locationOfBeganTap -> .\(locationOfBeganTap)")
        print("locationOfBeganTap in ENDED State -> .\(locationOfBeganTap)")

    }     
}

现在，这是输出：

locationOfBeganTap in BEGAN State -> .Optional((195.5, 120.0))
locationOfBeganTap in ENDED State -> .nil

我无法理解locationOfBeganTap状态nil为.Ended的原因

有人可以分享代码来访问locationOfBeganTap州内的.Ended ...

Answer 1

你这样做的方式不起作用。相反，最后计算一切：

func handleTestViewTap (panRecognizer: UIPanGestureRecognizer){

    if panRecognizer.state == UIGestureRecognizerState.Ended {            
        print("locationOfBeganTap -> (.\(touch.locationInView(view).x - touch.translationInView(view).x), .\(touch.locationInView(view).y - touch.translationInView(view).y))")
        print("location in ENDED State -> .\(touch.locationInView(view))")
    }     
}

Answer 2

您需要将locationOfBeganTap移动为实例变量而不是局部变量。

class WhatEverClassThisIs {
    var locationOfBeganTap: CGPoint?

    // and the rest of your stuff

    func handleTestViewTap (panRecognizer: UIPanGestureRecognizer){
        if panRecognizer.state == UIGestureRecognizerState.Began {           
            locationOfBeganTap = panRecognizer.locationInView(view)
            print("locationOfBeganTap in BEGAN State -> .\(locationOfBeganTap)")
        } else if panRecognizer.state == UIGestureRecognizerState.Ended {            
            print("locationOfBeganTap -> .\(locationOfBeganTap)")
            print("locationOfBeganTap in ENDED State -> .\(locationOfBeganTap)")
        }     
    }
}

如何访问其中的Pan Gesture的初始点.Ended状态

2 个答案: