问题
When user press [Return] key then need to display the number. Like serial numbers [1,2 etc] for each line.Is there any way to do that?
Following code I tried
func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
var textview_text_nssring = textView.text as NSString
// Add "1" when the user starts typing into the text field
if (range.location == 0 && textView.text.isEmpty ) {
if text == "\n" {
textView.text = "1."
let cursor = NSMakeRange(range.location + 3, 0)
textView.selectedRange = cursor
return false
}
else {
textView.text = NSString(format: "1. %@", text) as String
}
}
return true
}
回答1:
Declare one Int var for current line number and use it inside shouldChangeTextIn range like this way.
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
}
来源：https://stackoverflow.com/questions/39951546/how-to-make-auto-numbering-on-uitextview-when-press-return-key-in-swift