我想做一个操场,我有一个按钮,上面写着“让我们玩吧!”并移动到新的视图控制器。
我查看了这个网站的代码并将其放入我的代码中:
http://lab.dejaworks.com/ios-swift-3-playground-uibutton-action/
这是我的所有代码(比如,所有代码):
import UIKit
import PlaygroundSupport
class MyViewController : UIViewController {
override func loadView() {
//Introduction
let view = UIView()
view.backgroundColor = .red
//title
func labelCool() {
let label = UILabel()
label.frame = CGRect(x: 50, y: 300, width: 400, height: 100)
label.text = "Add-Add - A Wonderful Game!"
//label.frame = CGRect(x: 150, y: 200, width: 200, height: 20)
label.numberOfLines = 3
label.font = UIFont(name: "HelveticaNeue-Bold", size: 30)
UILabel.animate (withDuration: 10.0, animations:{
label.textColor = .black
})
UILabel.animate(withDuration: 5.0, animations:{
label.textColor = .blue
})
view.addSubview(label)
}
labelCool()
//subtitle
let subtitle = UILabel()
subtitle.frame = CGRect(x: 50, y: 400, width: 200, height: 50)
subtitle.text = "Curated and Created by Yours Truly, Adit Dayal!"
subtitle.numberOfLines = 4
self.view = view
view.addSubview(subtitle)
}
override func viewDidLoad() {
class Responder : NSObject {
@objc func action() {
print("Yay!")
}
}
let responder = Responder()
//next page
let button = UIButton(frame : CGRect(x: 0, y: 500, width: 200, height: 50))
button.setTitle("Let's Play!", for: .normal)
button.backgroundColor = .blue
button.addTarget(responder, action: #selector(Responder.action), for: .touchUpInside)
view.addSubview(button)
}
}
class gameViewController: UIViewController {
}
// Present the view controller in the Live View window
PlaygroundPage.current.liveView = MyViewController()
现在,我只想让按钮显示“Yay!”点击时,它什么也没做!有谁知道为什么? (我有点时间限制)
非常感谢,
Adit Dayal
你的Responder类在viewDidLoad()函数里面,把类放在外面就像这样
class Responder : NSObject {
@objc func action() {
print("Yay!")
}
}
override func viewDidLoad() {
let responder = Responder()
//next page
let button = UIButton(frame : CGRect(x: 0, y: 500, width: 200, height: 50))
button.setTitle("Let's Play!", for: .normal)
button.backgroundColor = .blue
button.addTarget(responder, action: #selector(responder.action), for: .touchUpInside)
view.addSubview(button)
}
问题是您在viewDidLoad
中创建响应器对象,作为局部变量;这会导致在函数结束时销毁对象(但我们希望该对象在之后仍然存在)。您必须保留该对象,因此不是创建局部变量,而是通过将其保存为类范围来创建实例变量:
class Responder : NSObject {
@objc func action() {
print("Yay!")
}
}
let responder = Responder() // this is now outside the viewDidLoad, so it's an instance variable
override func viewDidLoad() {
//next page
let button = UIButton(frame : CGRect(x: 0, y: 500, width: 200, height: 50))
button.setTitle("Let's Play!", for: .normal)
button.backgroundColor = .blue
button.addTarget(responder, action: #selector(Responder.action), for: .touchUpInside)
view.addSubview(button)
}