大佬教程收集整理的这篇文章主要介绍了ios – 如何识别触摸的图像，大佬教程大佬觉得挺不错的，现在分享给大家，也给大家做个参考。
这是我的DragImage类,它处理触摸：
class DragImages: UIImageView {
var originalPos : CGPoint!
var dropTarget: UIView?
override init (frame : CGRect){
super.init(frame: frame)
}
required init?(coder aDecoder : NSCoder){
super.init(coder : aDecoder)
}
override func touchesBegan(_ touches : Set<UITouch>,with event: UIEvent?){
originalPos = self.center
}
override func touchesMoved(_ touches: Set<UITouch>,with event: UIEvent?) {
if let touch = touches.first{
let position = touch.location(in: self.superview)
self.center = CGPoint(x : position.x,y : position.y)
}
}
override func touchesEnded(_ touches: Set<UITouch>,with event: UIEvent?) {
if let touch = touches.first,let target = dropTarget{
let position = touch.location(in: self.superview)
if target.frame.contains(position){
NotificationCenter.default.post(Notification(name: Notification.Name(rawValue: "onTargetDropped"),object: nil))
}else {
self.center = originalPos
}
}
print(self.center.x,self.center.y)
self.center = originalPos
}
func getEndPosX() -> CGFloat{
return self.center.x
}
func getEndPosY() -> CGFloat {
return self.center.y
}
}
在我的ViewController类中,我添加了这段代码来处理触摸等：
ornament1.dropTarget = xmasTree
ornament2.dropTarget = xmasTree
ornament3.dropTarget = xmasTree
ornament4.dropTarget = xmasTree
NotificationCenter.default.addObserver(self,selector: #selector(ViewController.itemDroppedOnTree(_:)),name: NSNotification.Name(rawValue: "onTargetDropped"),object: nil)
}
func itemDroppedOnTree(_ notif : AnyObject){
}
当图像在画布上拖动时,我设法得到X和Y位置,但是我无法找到一种方法来识别4个图像中的哪一个被丢弃,以便我绘制特定的图像！
NotificationCenter.default.post(Notification(name: Notification.Name(rawValue: "onTargetDropped"),object: self,userInfo: ["position":position]))
稍后在itemDroppedOnTree中获取它：
func itemDroppedOnTree(_ notif : NSNotification){
let position = notif.userInfo["position"]
let sender = notif.object as! DragImage
if sender === dragImage1 {
//...
} else if sender === dragImage2 {
//...
}
}
我建议反对它,并恳求使用委托来通知ViewController. (基于意见：通常,仅对多人广播使用通知.)
委托函数应将sender作为第一个参数.根据func tableView：tableView：UITableView,cellForRowAt indexPath：IndexPath).
通过这种方式,您可以知道哪个图像正在发送其新位置,并可以将其与您的属性进行比较,如上例所示：
if dragImage === dragImage1 {...
import UIKit
import PlaygroundSupport
protocol DragImageDelegate: class {
func dragimage(_ dragImage:DragImage,didDropAt position:CGPoint)
}
class DragImage: UIImageView {
weak var delegate: DragImageDelegate?
var originalPos : CGPoint!
var dropTarget: UIView?
override init (frame : CGRect) {
super.init(frame: frame)
isUserInteractionEnabled = true
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func touchesBegan(_ touches : Set<UITouch>,with event: UIEvent?) {
if let touch = touches.first,let target = dropTarget {
let position = touch.location(in: self.superview)
if target.frame.contains(position){
print(self.center.x,self.center.y)
guard let delegate = self.delegate else {
print("delegate not set")
return
}
print(self.center.x,self.center.y)
delegate.dragimage(self,didDropAt: position)
return
}
}
self.center = originalPos
}
}
class MyVC: UIViewController,DragImageDelegate {
let dragImage1 = DragImage(frame: CGRect(x: 0.0,y: 0.0,width: 30.0,height: 30.0))
let dragImage2 = DragImage(frame: CGRect(x: 0.0,y: 100.0,height: 30.0))
override func viewDidLoad() {
let target = UIView(frame: CGRect(x: 200.0,y: 400.0,height: 30.0))
target.backgroundColor = .black
view.addSubview(target)
dragImage1.backgroundColor = .white
dragImage2.backgroundColor = .white
dragImage1.dropTarget = target
dragImage2.dropTarget = target
view.addSubview(dragImage1)
view.addSubview(dragImage2)
dragImage1.delegate = self
dragImage2.delegate = self
}
private func move(_ view:UIView,to position:CGPoint) {
view.frame = CGRect(x: position.x,y: position.y,width: view.frame.size.width,height: view.frame.size.height)
}
// MARK: - DragImageDelegate
func dragimage(_ dragImage: DragImage,didDropAt position: CGPoint) {
if dragImage === dragImage1 {
move(dragImage1,to: position)
} else if dragImage === dragImage2 {
move(dragImage2,to: position)
}
}
}
var container = UIView(frame: CGRect(x: 0.0,width: 300.0,height: 600.0))
let myVc = MyVC()
myVc.view.frame = CGRect(x: 0.0,height: 600.0)
myVc.view.backgroundColor = .green
container.addSubview(myVc.view)
PlaygroundPage.current.liveView = container
结果：
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