swift - 如何显示用户输入的文本？ swift 3.0

Question

我是 swift (3.0) 语言的新手。我正在为 iOS 开发一个新的应用程序。如何创建一个文本框，用户可以在其中输入内容，按下按钮，然后在按钮下方显示文本？谢谢!

Answer 1

您可以使用 Storyboard或以编程方式执行此操作。这两个选项都适用于 Xcode 8 Swift 3

Storyboard

1. 将库中的 UITextField、UIButton 和 UILabel 拖到您的 View Controller 上
2. 为 UITextField 和 UILabel 创建一个 IBOutlet 到您的 ViewController.swift 文件。
3. 然后为 UIButton 创建一个 IBAction 到同一个 ViewController.swift 文件。

4. 在按钮的操作函数中编写此代码:

   myLabel.text = myTextField.text

你的整个代码应该是这样的:

import UIKit

class ViewController: UIViewController {

@IBOutlet weak var myTextField: UITextField!

@IBOutlet weak var myLabel: UILabel!

@IBAction func myButtonPressed(_ sender: AnyObject) {

    myLabel.text = myTextField.text

}

override func viewDidLoad() {
    super.viewDidLoad()

    // Do any additional setup after loading the view, typically from a nib.

}
}

或以编程方式:

import UIKit

class ViewController: UIViewController {

// First create your components

let myTextField: UITextField = {
    let textField = UITextField()
    textField.backgroundColor = .lightGray //Just so you can see it
    textField.translatesAutoresizingMaskIntoConstraints = false
    return textField
}()

let myLabel: UILabel = {
    let label = UILabel()
    label.text = "Label text" //You may want to set this to something else to start with
    label.textAlignment = .center
    label.translatesAutoresizingMaskIntoConstraints = false
    return label
}()

let myButton: UIButton = {
    let button = UIButton()
    button.setTitle("Press me", for: .normal)
    button.setTitleColor(UIColor.blue, for: .normal)
    button.translatesAutoresizingMaskIntoConstraints = false
    return button
}()

//Then add them as subViews in the viewDidLoad method and set some constraints. 

override func viewDidLoad() {
    super.viewDidLoad()

    view.addSubview(myTextField)
    myTextField.widthAnchor.constraint(equalToConstant: 250).isActive = true
    myTextField.heightAnchor.constraint(equalToConstant: 50).isActive = true
    NSLayoutConstraint(item: myTextField, attribute: .centerX, relatedBy: .equal, toItem: view, attribute: .centerX, multiplier: 1, constant: 0).isActive = true
    NSLayoutConstraint(item: myTextField, attribute: .centerY, relatedBy: .equal, toItem: view, attribute: .centerY, multiplier: 1, constant: -100).isActive = true

    view.addSubview(myLabel)
    myLabel.widthAnchor.constraint(equalToConstant: 250).isActive = true
    myLabel.heightAnchor.constraint(equalToConstant: 50).isActive = true
    NSLayoutConstraint(item: myLabel, attribute: .centerX, relatedBy: .equal, toItem: view, attribute: .centerX, multiplier: 1, constant: 0).isActive = true
    NSLayoutConstraint(item: myLabel, attribute: .centerY, relatedBy: .equal, toItem: view, attribute: .centerY, multiplier: 1, constant: 0).isActive = true


    view.addSubview(myButton)
    myButton.widthAnchor.constraint(equalToConstant: 250).isActive = true
    myButton.heightAnchor.constraint(equalToConstant: 50).isActive = true
    NSLayoutConstraint(item: myButton, attribute: .centerX, relatedBy: .equal, toItem: view, attribute: .centerX, multiplier: 1, constant: 0).isActive = true
    NSLayoutConstraint(item: myButton, attribute: .top, relatedBy: .equal, toItem: myTextField, attribute: .bottom, multiplier: 1, constant: 10).isActive = true

//This sets the function for when the button is pressed 
    myButton.addTarget(self, action: #selector(ViewController.myButtonPressed), for: .touchUpInside)
}

//Add code here to when the button is pressed
func myButtonPressed() {

    myLabel.text = myTextField.text

}

}