[英]How do I get the value of a UITextfield as characters are being typed in real time?
I am attempting to regulate the input of a UITextfield in real time, meaning as a user is typing.我正在尝试实时调节 UITextfield 的输入,这意味着用户正在输入。 I have this character set that i need to compare to the input string, and while editing if an unwarranted character is typed in, I want to relay an alert.我有这个字符集需要与输入字符串进行比较,并且在编辑时是否输入了无根据的字符,我想中继警报。 Here is my character set :这是我的字符集:
let acceptedChars = NSCharacterSet(charactersInString: "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890_")
now how do i capture a specific textfield in real time and track its input?现在如何实时捕获特定的文本字段并跟踪其输入?
Try this:尝试这个:
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
let invalidCharacters = NSCharacterSet(charactersInString: "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890_").invertedSet
if let range = string.rangeOfCharacterFromSet(invalidCharacters, options: nil, range:Range<String.Index>(start: string.startIndex, end: string.endIndex)) {
return false
}
return true
}
You can register your textField for value change event like this您可以像这样为值更改事件注册 textField
textfield.addTarget(self, action:"textFieldDidChange", forControlEvents:UIControlEvents.EditingChanged)
func textFieldDidChange(){
// put your code
}
It will work for each chracter you have been typed in real time它适用于您实时输入的每个字符
var strings: NSString?
class ViewController: UIViewController,UITextFieldDelegate //set your textfield delegate class ViewController: UIViewController,UITextFieldDelegate //设置你的文本框委托
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool
{ if(textField .isEqual(your textfield))
{
strings=string;
let acceptedChars = NSCharacterSet(charactersInString: "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890_").invertedSet;
if (strings!.rangeOfCharacterFromSet(acceptedChars.invertedSet).location != NSNotFound)
{
return true;
}
else
{
return false;
}
}
else
{
return true;
}
}
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool
{
if textField.isEqual(<textField whose value to be copied>)
{
<TextField to be updated>.text = (textField.text as NSString).stringByReplacingCharactersInRange(range, withString: string)
}
return true
}
An Easy Delegate method and really more efficient is:一个简单的委托方法,真正更有效的是:
func textFieldDidChangeSelection(_ textField: UITextField) {
print(textField.text)
}
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