防止UITextField中的特殊字符

Question

如何防止用戶在UITextField中輸入特殊字符？

Answer 1

我解決了使用此代碼的問題：

let validString = NSCharacterSet(charactersInString: " !@#$%^&*()_+{}[]|\"<>,.~`/:;?-=\\¥'£•¢") 

// restrict special char in test field 
if (textField == self.txt_firstName || textField == self.txt_lastName) 
{ 
    if let range = string.rangeOfCharacterFromSet(validString) 
    { 
     print(range) 
     return false 
    } 
    else 
    { 
    } 
}