swift - 如何在 TextView 中更改某些文本的颜色？

Question

我为 View Controller 的生命周期做了功课。我使用标签栏来切换 Controller 。并且在切换 Controller 时， TextView 的标签显示生命周期方法。

现在我想更改 TextView 中表达式“First Controller”、“Second Controller”、“Third Controller”的颜色文本，以便无论我切换到哪个 Controller ，颜色都保持不变。

https://youtu.be/Od_bFlaA-kY

怎么做？

import UIKit

class FirstViewController: UIViewController {
    @IBOutlet var firstTextView: UITextView!

    override func viewDidLoad() {
        super.viewDidLoad()
        FromCodeToScreen.shared.printMessage(textView: firstTextView, viewController: self)
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        FromCodeToScreen.shared.printMessage(textView: firstTextView, viewController: self)
    }

    override func viewDidAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        FromCodeToScreen.shared.printMessage(textView: firstTextView, viewController: self)
    }

    // And similar code in all of the other lifecycle methods
}

import UIKit

class FromCodeToScreen: NSObject {
    static let shared = FromCodeToScreen()
    private var arrayForData = [String]()

    private override init() {
        super.init()
    }

    func printMessage(textView: UITextView, viewController: UIViewController, function: String = #function) {
        arrayForData.append((viewController.title ?? "nil") + " - " + (function))
        let string = arrayForData.joined(separator: "\n")
        textView.text = string

        textViewScrollToBottom(textView)
    }
}

Answer 1

将 arrayForData 字符串数组更改为 NSAttributedString。

class FromCodeToScreen: NSObject {

    static let shared = FromCodeToScreen()
    private var arrayForData = [NSAttributedString]()

    private override init() {
        super.init()
    }
    func printMessage(textView: UITextView, viewController: UIViewController, function: String = #function) {

        let color = viewController.view.backgroundColor ?? .white
        let attStr = NSMutableAttributedString(string: viewController.title ?? "nil", attributes: [.foregroundColor : color])
        attStr.append(NSAttributedString(string: " - " + function + "\n"))
        arrayForData.append(attStr)
        textView.attributedText = arrayForData.reduce(into: NSMutableAttributedString()) { $0.append($1) }
        textViewScrollToBottom(textView)
    }
}