ios 设置`UITextView`和`UITextField`的最大字符数
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Setting maximum number of characters of `UITextView ` and `UITextField `
提问by biggreentree
I'd like to set a maximum number of characters allowed to be typed both in a UITextViewand a UITextField. This number will be then shown in a little label (for user's reference, Twitter Style.)
我想设置允许在 aUITextView和 a 中输入的最大字符数UITextField。然后这个数字将显示在一个小标签中（供用户参考，Twitter 样式。）
回答by Abhinav
Update Swift 4.X
更新Swift 4.X
func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
let newText = (textView.text as NSString).replacingCharacters(in: range, with: text)
let numberOfChars = newText.count
return numberOfChars < 10 // 10 Limit Value
}
Try this out:
试试这个：
func textView(textView: UITextView, shouldChangeTextInRange range: NSRange, replacementText text: String) -> Bool {
let newText = (textView.text as NSString).stringByReplacingCharactersInRange(range, withString: text)
let numberOfChars = newText.characters.count // for Swift use count(newText)
return numberOfChars < 10;
}
回答by Maksim Kniazev
SWIFT 4
快速 4
func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
let newText = (textView.text as NSString).replacingCharacters(in: range, with: text)
return newText.count < 10
}
回答by Bogdan Bystritskiy
Swift 4:
斯威夫特 4：
func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
let newText = (textView.text as NSString).replacingCharacters(in: range, with: text)
return newText.count <= 70
}
回答by Abhijeet Mallick
Try this out:-
试试这个：-
func textView(textView: UITextView, shouldChangeTextInRange range: NSRange, replacementText text: String) -> Bool {
print("chars \(textView.text.characters.count) \( text)")
if(textView.text.characters.count > 20 && range.length == 0) {
print("Please summarize in 20 characters or less")
return false;
}
return true;
}
回答by Junaid Mukhtar
Swift 3.0
斯威夫特 3.0
Just override this UITextFieldDelegate function, set the desired characterLimit variable and you are good to go:
只需覆盖此 UITextFieldDelegate 函数，设置所需的 characterLimit 变量即可：
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool
{
let characterLimit = 5
let newText = NSString(string: textField.text!).replacingCharacters(in: range, with: string)
let numberOfChars = newText.characters.count
return numberOfChars < characterLimit
}
回答by Arpit Jain
Swift 4/ Xcode 9.1
斯威夫特 4/ Xcode 9.1
func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
let currentText = textView.text ?? ""
guard let stringRange = Range(range, in: currentText) else { return false }
let changedText = currentText.replacingCharacters(in: stringRange, with: text)
return changedText.count <= 399 // Pass your character count here
}
回答by Gerasim
Swift 5
斯威夫特 5
func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
var newText = textView.text!
newText.removeAll { (character) -> Bool in
return character == " " || character == "\n"
}
return (newText.count + text.count) <= 40
}
回答by Krunal Patel
Swift 4 , Xcode 9.1 GM
斯威夫特 4 , Xcode 9.1 通用
func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
return textView.text.count + (text.count - range.length) <= 200
}
