Ios 如何避免swift中出现太多新行

我使用文本视图为用户输入内容，但我无法限制用户点击enter键创建新行的次数，如何将文本视图最多限制为2行

例如：

当前

"Start





end"

期望的：

"limit


2 


empty lines"

---

您可以将视图控制器设置为文本视图的代理，并使用replacingOccurrences将4行或更多新行替换为3行新行，您还需要避免在字符串开头出现新行：

class ViewController: UIViewController, UITextViewDelegate {

    @IBOutlet weak var textView: UITextView!
    override func viewDidLoad() {
        super.viewDidLoad()
        textView.delegate = self
    }
    func textViewDidChange(_ textView: UITextView) {
        // avoid new lines also at the beginning
        textView.text = textView.text.replacingOccurrences(of: "^\n", with: "", options: .regularExpression)
        // avoids 4 or more new lines after some text
        textView.text = textView.text.replacingOccurrences(of: "\n{4,}", with: "\n\n\n", options: .regularExpression)
    }
}

---

您可以将视图控制器设置为文本视图的代理，并使用replacingOccurrences将4行或更多新行替换为3行新行，您还需要避免在字符串开头出现新行：

class ViewController: UIViewController, UITextViewDelegate {

    @IBOutlet weak var textView: UITextView!
    override func viewDidLoad() {
        super.viewDidLoad()
        textView.delegate = self
    }
    func textViewDidChange(_ textView: UITextView) {
        // avoid new lines also at the beginning
        textView.text = textView.text.replacingOccurrences(of: "^\n", with: "", options: .regularExpression)
        // avoids 4 or more new lines after some text
        textView.text = textView.text.replacingOccurrences(of: "\n{4,}", with: "\n\n\n", options: .regularExpression)
    }
}

---

那有助于感谢老板那有助于感谢老板