如何使用Swift創(chuàng)建帶屬性的字符串？

本文將解釋如何在Swift語言中創(chuàng)建帶屬性的字符串。愛掏網(wǎng) - it200.com在Swift中，要對字符串應(yīng)用不同的屬性，需要進(jìn)行哪些步驟？

在Swift中，我們使用NSAttributedString類來創(chuàng)建帶屬性的字符串。愛掏網(wǎng) - it200.com

在Swift中，NSAttributedString是一個(gè)用于創(chuàng)建和管理帶屬性的字符串的類。愛掏網(wǎng) - it200.com帶屬性的字符串是一個(gè)在字符串的部分文本上應(yīng)用了額外屬性（如文字顏色、字體和樣式）的字符串。愛掏網(wǎng) - it200.com

本文將展示帶屬性的字符串的不同用例。愛掏網(wǎng) - it200.com

import UIKit
class TestController: UIViewController {
    private let attributedLabel = UILabel()

    override func viewDidLoad() {
        super.viewDidLoad()
        initialSetup()
    }
    private func initialSetup() {

        // basic setup
        view.backgroundColor = .white
        navigationItem.title = "NSAttributedString"


        // attributedLabel customization
        attributedLabel.numberOfLines = 0
        attributedLabel.backgroundColor = UIColor(white: 0, alpha: 0.1)

        view.addSubview(attributedLabel)
        attributedLabel.translatesAutoresizingMaskIntoConstraints = false
        attributedLabel.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 30).isActive = true
        attributedLabel.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -30).isActive = true
        attributedLabel.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 30).isActive = true
        attributedLabel.heightAnchor.constraint(equalToConstant: 300).isActive = true
    }
}

解釋

在上面的代碼中，我們設(shè)置了一個(gè)名為TestController的視圖控制器，用于為UILabel類顯示不同的屬性文本。愛掏網(wǎng) - it200.com

輸出

如何給整個(gè)字符串應(yīng)用顏色？

在這個(gè)例子中，您將看到如何給整個(gè)字符串應(yīng)用顏色。愛掏網(wǎng) - it200.com以下是使用不同屬性在Swift中創(chuàng)建NSAttributedString對象的示例 –

private func example1() {
   let string = "Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book."
   let attributes: [NSAttributedString.Key: Any] = [.foregroundColor: UIColor.red,
   let attributedString = NSAttributedString(string: string, attributes: attributes)
   attributedLabel.attributedText = attributedString
}

輸出

如何對整個(gè)字符串應(yīng)用不同的顏色和字體樣式？

在這個(gè)示例中，您將看到如何對字符串應(yīng)用不同的顏色和字體樣式的示例。愛掏網(wǎng) - it200.com以下是在Swift中創(chuàng)建帶有不同屬性的NSAttributedString對象的示例-

private func example2() {
   // first part
   let attributedString = NSMutableAttributedString(string: "This is the first line of black color. We're not applying any attribute to this part of string.",
      attributes: [.foregroundColor: UIColor.black, font: UIFont.systemFont(ofSize: 17)])

   // appending new lines
   attributedString.append(NSAttributedString(string: "\n\n"))

   // second part
   attributedString.append(NSAttributedString(string: "This part will be in Red color and bold style in the string.", attributes: [.foregroundColor: UIColor.red, .font: UIFont.systemFont(ofSize: 17, weight: .bold)]))

   // appending new lines
   attributedString.append(NSAttributedString(string: "\n\n"))

   // third part
   attributedString.append(NSAttributedString(string: "This part will be in Brown color and underline style in the string.", attributes: [.foregroundColor: UIColor.brown, .font: UIFont.systemFont(ofSize: 17), .underlineStyle: 1]))

   attributedLabel.attributedText = attributedString
}

輸出

如何對整個(gè)字符串應(yīng)用行間距？

在許多情況下，您必須對字符串應(yīng)用一些行間距以正確顯示多行文本。愛掏網(wǎng) - it200.comSwift提供了NSMutableParagraphStyle類來添加行之間的間距。愛掏網(wǎng) - it200.com以下是如何在Swift中將段落樣式應(yīng)用于字符串的示例?

private func example3() {
   let string = "Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book."
   let paragraph = NSMutableParagraphStyle()
   paragraph.lineSpacing = 7
   let attributes: [NSAttributedString.Key: Any] = [.foregroundColor: UIColor.red,
      .font: UIFont.systemFont(ofSize: 17),
      .paragraphStyle: paragraph]
   let attributedString = NSAttributedString(string: string, attributes: attributes)
   attributedLabel.attributedText = attributedString
}

輸出

結(jié)論

在真實(shí)的iOS應(yīng)用中，屬性字符串是一個(gè)非常有用和常用的功能。愛掏網(wǎng) - it200.com你可以對字符串應(yīng)用不同的樣式。愛掏網(wǎng) - it200.com同時(shí)，你還可以對子字符串應(yīng)用不同的樣式。愛掏網(wǎng) - it200.com