我正在尝试从用户输入到UITextView的信息中创建一个编号列表。例如,
这是我尝试过的代码,但没有给我预期的效果。 var currentLine:Int = 1
func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
// Add "1" when the user starts typing into the text field
if (textView.text.isEmpty && !text.isEmpty) {
textView.text = "\(currentLine). "
currentLine += 1
}
else {
if text.isEmpty {
if textView.text.characters.count >= 4 {
let str = textView.text.substring(from:textView.text.index(textView.text.endIndex, offsetBy: -4))
if str.hasPrefix("\n") {
textView.text = String(textView.text.characters.dropLast(3))
currentLine -= 1
}
}
else if text.isEmpty && textView.text.characters.count == 3 {
textView.text = String(textView.text.characters.dropLast(3))
currentLine = 1
}
}
else {
let str = textView.text.substring(from:textView.text.index(textView.text.endIndex, offsetBy: -1))
if str == "\n" {
textView.text = "\(textView.text!)\(currentLine). "
currentLine += 1
}
}
}
return true
}
如此处所示:How to make auto numbering on UITextview when press return key in swift但没有成功。
非常感谢任何帮助。
答案 0 :(得分:0)
您可以继承UITextView,覆盖方法willMove(toSuperview并为UITextViewTextDidChange添加一个观察者,使用一个选择器将您的文本分解为枚举和编号的行。请尝试这样:
class NumberedTextView: UITextView {
override func willMove(toSuperview newSuperview: UIView?) {
frame = newSuperview?.frame.insetBy(dx: 50, dy: 80) ?? frame
backgroundColor = .lightGray
NotificationCenter.default.addObserver(self, selector: #selector(textViewDidChange), name: .UITextViewTextDidChange, object: nil)
}
func textViewDidChange(notification: Notification) {
var lines: [String] = []
for (index, line) in text.components(separatedBy: .newlines).enumerated() {
if !line.hasPrefix("\(index.advanced(by: 1))") &&
!line.trimmingCharacters(in: .whitespaces).isEmpty {
lines.append("\(index.advanced(by: 1)). " + line)
} else {
lines.append(line)
}
}
text = lines.joined(separator: "\n")
// this prevents two empty lines at the bottom
if text.hasSuffix("\n\n") {
text = String(text.characters.dropLast())
}
}
}
import UIKit
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let textView = NumberedTextView()
view.addSubview(textView)
}
}