ios - 如何以编程方式快速从标签中的文本字段打印文本

Question

我喜欢通过单击按钮键来打印标签中的文本字段值。但我一直无法做到。下面是代码

import UIKit

class MainViewController: UIViewController {


 override func viewDidLoad() {

super.viewDidLoad()


view.backgroundColor = UIColor.gray
setupLabel()
setupTextField()
setupButton()
}

func setupLabel() {

let label = UILabel()
label.frame = CGRect(x: 40, y: 80, width: 300, height: 60)
label.text = "welcome to my world"
label.textColor = UIColor.yellow
label.font = UIFont.boldSystemFont(ofSize: 25)
label.textAlignment = .center
label.layer.borderWidth = 2
label.layer.borderColor = UIColor.yellow.cgColor
label.layer.cornerRadius = 5
view.addSubview(label)
}

func setupTextField() {

let textField = UITextField()
textField.frame = CGRect(x: 10, y: 200, width:   self.view.frame.size.width - 20, height: 60)
textField.placeholder = "text here"
textField.textAlignment = .center
textField.font = UIFont.systemFont(ofSize: 25)
textField.layer.borderWidth = 2
textField.layer.borderColor = UIColor.yellow.cgColor
textField.layer.cornerRadius = 5
view.addSubview(textField)
 }

 func setupButton() {

let button = UIButton()
button.frame = CGRect(x: 50, y: 300, width: self.view.frame.size.width - 100, height: 60)
button.setTitle("Enter", for: .normal)
button.setTitleColor(UIColor.yellow, for: .normal)
button.layer.borderWidth = 2
button.layer.borderColor = UIColor.yellow.cgColor
button.layer.cornerRadius = 5
button.addTarget(self, action: #selector(buttonTarget), for: .touchUpInside)
view.addSubview(button)
  }

  func buttonTarget() {


// i  missed of here

  }
}

Answer 1

在这里您需要执行两个步骤

you need to create the label and textfield in globally not instance, for e.g

class MainViewController: UIViewController
  let label = UILabel()
  let textField = UITextField()

隐藏分配的实例值

  func setupLabel() {

//let label = UILabel()
label.frame = CGRect(x: 40, y: 80, width: 300, height: 60)
label.text = "welcome to my world"
label.textColor = UIColor.yellow
label.font = UIFont.boldSystemFont(ofSize: 25)
label.textAlignment = .center
label.layer.borderWidth = 2
label.layer.borderColor = UIColor.yellow.cgColor
label.layer.cornerRadius = 5
view.addSubview(label)
}

然后您可以直接在类中的任何位置访问该值

func buttonTarget() {

 if let text = textField.text
    {
        label.text = text
    }

}