每次我运行这个快速的游乐场(在Xcode上),我在最后一行收到错误说:
' PlaygroundView'无法构建,因为它没有可访问的初始化程序。
我在第4行还有另一个错误:
class' PlaygroundView'没有初始化器。
import UIKit
import PlaygroundSupport
class PlaygroundView:UIViewController {
var introImage:UIImageView
var introButton:UIButton
override func loadView() {
print("workspace started running.")
//Main Constant and Variable Declarations/General Setup
let mainView = UIView()
//Main View Modifications & styling
mainView.backgroundColor = UIColor.init(colorLiteralRed: 250, green: 250, blue: 250, alpha: 1)
func addItem(item: UIView) {
mainView.addSubview(item)
}
//Sub-Element Constant and Variable Declarations
introImage = UIImageView(frame: CGRect(x: 87.5, y: -300, width: 200, height: 200))
introImage.layer.borderColor = UIColor.black.cgColor
introImage.layer.borderWidth = 4
introImage.alpha = 0
introImage.transform = CGAffineTransform(rotationAngle: -90.0 * 3.14/180.0)
introImage.image = UIImage(named: "profile_pic.png")
introImage.image?.accessibilityFrame = introImage.frame
introImage.layer.cornerRadius = 100
addItem(item: introImage)
introButton = UIButton(frame: CGRect(x: 87.5, y: 900, width: 200, height: 30))
introButton.alpha = 0
introButton.setTitle("Tap to meet me", for: .normal)
introButton.titleLabel?.font = UIFont(name: "Avenir Book", size: 20)
introButton.backgroundColor = UIColor.black
introButton.layer.cornerRadius = 15
introButton.layer.borderWidth = 5
addItem(item: introButton)
introButton.addTarget(self, action: #selector(self.introButtonAction), for: .touchDown)
UIView.animate(withDuration: 1.5, delay: 1, options: .curveEaseInOut, animations: {
self.introImage.frame = CGRect(x: 87.5, y: 175, width: 200, height: 200)
self.introButton.frame = CGRect(x: 87.5, y: 400, width: 200, height: 30)
self.introImage.transform = CGAffineTransform(rotationAngle: 0.0 * 3.14/180.0)
self.introImage.alpha = 1
self.introButton.alpha = 1
}) { (mainAnimationComped) in
if mainAnimationComped == true {
print("introduction animation comped.")
}
}
}
//User Interface Actions
func introButtonAction() {
print("user interacted with user interface")
}
}
PlaygroundPage.current.liveView = PlaygroundView()
我该如何解决这个问题?
答案 0 :(得分:0)
添加?在introImage和introButton之后
var introImage:UIImageView?
var introButton:UIButton?
答案 1 :(得分:0)
那是因为在Swift中,你需要在代码中使用它们之前初始化变量。另一方面,因为在这种情况下,您在函数中显式设置它们,您可以将它们声明为隐式解包的选项
var introImage:UIImageView!
var introButton:UIButton!
这应该可以在不更改代码中的任何其他内容的情况下使用