我是 swift 的新手，一整天都在研究这段代码。我想我知道问题出在哪里，但我不太确定如何解决。我有一个包含 UIImageView 的 View Controller ，我希望在用户输入 touchesMoved 函数时在每个触摸点简单地制作同一个 UIImageView 的多个副本。我创建了一个数组来存储用户触摸过的所有位置的元素，并在 touchesMoved 函数中使用 array.append 来收集点。然后我创建了一个循环，该循环将读取这些 CGPoints 并将 UIImageView 分配给该点。问题是 CGPoints 不能转换为 UIImageViews。关于如何解决这个问题有什么建议吗？
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]
这是一种使用 CALayer 的不同方法。我使用它是因为 1. 我发现 UIImageView 副本意味着性能不佳 2. 对于我制作的每五层副本，我希望能够将图层的 contentsScale 动画化 120%。我意识到现在的动画是针对 cornerRadius 的，但这是我唯一需要处理的动画。语法没问题，但我认为我的语义仍然有点偏差。图像在我拖动时跟随我的光标，我认为正在创建图层，因为轨迹中只有一点点滞后。我似乎无法让图像填充到图层中以实际形成用户拖动的路径。在尝试这种新方法时，我将不胜感激。
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
}
最佳答案
删除 var Person = waypoints[i] 行并将其替换为以下内容:
for (n, child) in enumerate(containerView.subviews) {
(child as UIView).removeFromSuperview()
}
var newPerson = UIImageView(image: Person.image)
newPerson.position = waypoints[i]
containerView.addSubview(newPerson)
其中 containerView 是您为包含 ImageView 而设置的 UIView。
作为旁注:请不要使用大写名称命名变量，这些名称应保留用于类型(类协议(protocol)、结构等)
关于ios - Swift:沿 touchesMoved 路径创建多个 UIImageView 副本，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/28313301/