swift - 如何更改文本视图中某些文本的颜色？

Question

我为视图控制器的生命周期做了功课。我使用标签栏来切换控制器。并且在切换控制器时，文本视图的标签显示生命周期方法。

现在我想在文本视图中更改表达式“第一个控制器”、“第二个控制器”、“第三个控制器”的颜色文本，以便无论我切换到哪个控制器，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)
    }
}

Answer 2

尝试这个

let text = "This is a colorful attributed string"
let attributedText = 
NSMutableAttributedString.getAttributedString(fromString: text)
attributedText.apply(color: .red, subString: "This")
//Apply yellow color on range
attributedText.apply(color: .yellow, onRange: NSMakeRange(5, 4))


For more detail click here: https://github.com/iOSTechHub/AttributedString

Answer 3

尝试：

firstTextView.textColor = UIColor.red

将此应用于每个 ViewController 的 viewDidLoad()。

将颜色更改为您想要的任何颜色。