UITextField，UITextView字数限制（swift）

在开发中, 有些时候会碰到这样的需求: 希望输入框有最大字数限制. 比如, 用户昵称长度限制, 评论最大字数限制.下面我就介绍一种方法，希望能帮到你！

import UIKit

class ViewController: UIViewController{

@IBOutlet var textField: UITextField!
@IBOutlet var textView: UITextView!

let MAX_STARWORDS_LENGTH = 10

override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
NotificationCenter.default.addObserver(self, selector: #selector(self.textFiledEditChanged(sender:)), name: NSNotification.Name.UITextFieldTextDidChange, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(textViewEditChanged(sender:)), name: NSNotification.Name.UITextViewTextDidChange, object: nil);
}

func textFiledEditChanged(sender:NSNotification) {
print(textField.text! as String)
let lang = textInputMode?.primaryLanguage
if lang == "zh-Hans" {
let range = textField.markedTextRange
if range == nil {
if (textField.text?.characters.count)! >= MAX_STARWORDS_LENGTH {
textField.text = textField.text?.substring(to: (textField.text?.index(textField.text!.startIndex, offsetBy: MAX_STARWORDS_LENGTH))!)
}
}
}
else {
if (textField.text?.characters.count)! >= MAX_STARWORDS_LENGTH {
textField.text = textField.text?.substring(to: (textField.text?.index(textField.text!.startIndex, offsetBy: MAX_STARWORDS_LENGTH))!)
}
}
}

func textViewEditChanged(sender:NSNotification) {
let textVStr = textView.text as NSString
if (textVStr.length >= MAX_STARWORDS_LENGTH) {
let str = textVStr.substring(to: MAX_STARWORDS_LENGTH)
textView.text = str
}
}

override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}

}

赶快试试吧，哈哈哈～～～