Question

我是swift的新手，整天都在使用这段代码。我想我知道问题在哪里，但我不太清楚如何解决它。我有一个包含UIImageView的视图控制器，我希望在用户输入touchesMoved函数时，在每个触摸点简单地制作相同UIImageView的多个副本。我创建了一个数组来存储用户触摸的所有位置的元素，并在touchesMoved函数中使用array.append来收集点。然后我创建了一个循环，它将读取这些CGPoints并分配一个UIImageView。问题是CGPoints不能转换为UIImageViews。关于如何解决这个问题的任何建议？

import UIKit
import CoreGraphics

class ViewController: UIViewController {

    var wayPoints: [CGPoint] = []
    var location = CGPoint(x: 0, y: 0)

    @IBOutlet var Person : UIImageView!

    func movePoint (){
        for var i = 0; i < wayPoints.count; ++i {
            let p = wayPoints[i]

            if i == 0 {
                CGPointMake(p.x, p.y)
            }
            else {
                CGPointMake(p.x, p.y)
            }

            var Person = wayPoints[i]

        }
    }

    override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
        var touch : UITouch! = touches.anyObject() as UITouch
        location = touch.locationInView(self.view)
        Person.center = location

    }

    override func touchesMoved(touches: NSSet, withEvent event: UIEvent) {
        var touch : UITouch! = touches.anyObject() as UITouch
        location = touch.locationInView(self.view)
        Person.center = location
        wayPoints.append(location)

    }


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

        Person.center = CGPointMake(0, 0)


    }

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


}

[编辑]

使用CALayer这有点不同。我使用它是因为1.我发现UIImageView副本意味着性能不佳，而且我每制作五层副本，我希望能够将图层的contentsScale设置为120％的动画。我现在意识到动画是适用于cornerRadius，但这是我唯一能够工作的动画。语法没问题，但我认为我的语义仍然有点偏。当我拖动时，图像跟随我的光标，我认为正在创建图层，因为在路径中只有一点滞后。我似乎无法在图层中填充图像以实际形成用户拖动的路径。我尝试这种新方法时会很感激。

import UIKit
import QuartzCore

class ViewController: UIViewController {

let imageLayer = CALayer()
let image = UIImage(named: "at")!
var wayPoints: [CGPoint] = []
var layers: [CALayer] = []
var images: [UIImage] = []
var location = CGPoint(x: 0, y: 0)


override func viewDidLoad() {
    super.viewDidLoad()

}

func setup() {
    imageLayer.contents = image.CGImage

    imageLayer.frame = CGRect(x: 50, y: 50, width: 50, height: 50)
    imageLayer.backgroundColor = UIColor.redColor().CGColor

    // Round corners
    imageLayer.cornerRadius = 25

    // Set border
    imageLayer.borderColor = UIColor.blackColor().CGColor
    imageLayer.borderWidth = 10

    imageLayer.shadowColor = UIColor.blackColor().CGColor
    imageLayer.shadowOpacity = 0.8
    imageLayer.shadowOffset = CGSizeMake(2, 2)
    imageLayer.shadowRadius = 3

    imageLayer.frame = CGRect(x: 0, y: 100, width: 200, height: 200)
    imageLayer.contentsGravity = kCAGravityResizeAspect
    imageLayer.contentsScale = imageLayer.contentsScale
    self.view.layer.addSublayer(imageLayer)

    for var i = 0; i < wayPoints.count; ++i {

        let p = wayPoints[i]

        if i == 0 {
            CGPointMake(p.x, p.y)
        }
        else {
            CGPointMake(p.x, p.y)
        }

        var newLayer = CALayer()
        newLayer.position = wayPoints[i]
        var newImage = UIImage(named: "at")!
        newLayer.contents = newImage.CGImage

        layers.append(newLayer)
        images.append(newImage)


        }

}

// Animate button would trigger this function to fire
func animate(){
    for (index, value) in enumerate(layers){
            if index % 5 == 0 {
                let animation = CABasicAnimation(keyPath: "cornerRadius")

                animation.fromValue = value.cornerRadius

                animation.toValue = 0

                animation.repeatCount = 1000

                imageLayer.addAnimation(animation, forKey: "cornerRadius")
            }

            else {
                let animation = CABasicAnimation(keyPath: "cornerRadius")

                animation.fromValue = value.cornerRadius

                animation.toValue = 25

                animation.repeatCount = 1000

                imageLayer.addAnimation(animation, forKey: "cornerRadius")

        }


    }
}

override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
    var touch : UITouch! = touches.anyObject() as UITouch
    location = touch.locationInView(self.view)
    imageLayer.position = location
    setup()

}

override func touchesMoved(touches: NSSet, withEvent event: UIEvent) {
    var touch : UITouch! = touches.anyObject() as UITouch
    //        var point: CGPoint = touches.anyObject() as UITouch
    location = touch.locationInView(self.view)
    wayPoints.append(location)
    setup()
    imageLayer.position = location

}

}

Answer 1

删除var Person = waypoints[i]行并将其替换为：

for (n, child) in enumerate(containerView.subviews) {
    (child as UIView).removeFromSuperview()
}
var newPerson = UIImageView(image: Person.image)
newPerson.position = waypoints[i]
containerView.addSubview(newPerson)

containerView是您为了包含图片视图而设置的UIView。

作为旁注：请不要使用UpperCase名称命名变量，这些变量应保留用于类型（类协议，结构等）

Answer 2

看起来更像是移动现有图像而不是创建新图像。

做@joshua所说的但确保你实际上在touchesMoved（）中调用你的movePoint（）方法。现在它永远不会被召唤。

作为旁注，根据您使用的图像和其他依赖于上下文的变量，您尝试执行的操作可能会产生“缓慢/缓慢”的结果。

Swift：沿touchesMoved路径创建多个UIImageView副本

2 个答案: