如何在UITextView中实现简单的"实时"字数

import UIKit

class ViewController: UIViewController, UITextViewDelegate {
    @IBOutlet weak var textView: UITextView!
    @IBOutlet weak var characterCountLabel: UILabel!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 设置UITextView的代理为当前视图控制器
        textView.delegate = self
    }
    
    func textViewDidChange(_ textView: UITextView) {
        // 获取UITextView的文本内容
        let text = textView.text ?? ""
        
        // 计算字符数
        let characterCount = text.count
        
        // 更新UILabel显示字符数
        characterCountLabel.text = "字符数：\(characterCount)"
    }
}