UITextField text change event

Question

How can I detect any text changes in a textField? The delegate method shouldChangeCharactersInRange works for something, but it did not fulfill my need exactly. Since until it returns YES, the textField texts are not available to other observer methods.

e.g. in my code calculateAndUpdateTextFields did not get the updated text, the user has typed.

Is their any way to get something like textChanged Java event handler.

- (BOOL)textField:(UITextField *)textField 
            shouldChangeCharactersInRange:(NSRange)range 
            replacementString:(NSString *)string 
{
    if (textField.tag == kTextFieldTagSubtotal 
        || textField.tag == kTextFieldTagSubtotalDecimal
        || textField.tag == kTextFieldTagShipping
        || textField.tag == kTextFieldTagShippingDecimal) 
    {
        [self calculateAndUpdateTextFields];

    }

    return YES;
}

Answer 1

You should use the notification to solve this problem,because the other method will listen to the input box not the actually input,especially when you use the Chinese input method. In viewDidload

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textFiledEditChanged:)
                                                 name:@"UITextFieldTextDidChangeNotification"
                                               object:youTarget];

then

- (void)textFiledEditChanged:(NSNotification *)obj {
UITextField *textField = (UITextField *)obj.object;
NSString *toBestring = textField.text;
NSArray *currentar = [UITextInputMode activeInputModes];
UITextInputMode *currentMode = [currentar firstObject];
if ([currentMode.primaryLanguage isEqualToString:@"zh-Hans"]) {
    UITextRange *selectedRange = [textField markedTextRange];
    UITextPosition *position = [textField positionFromPosition:selectedRange.start offset:0];
    if (!position) {
        if (toBestring.length > kMaxLength)
            textField.text =  toBestring;
} 

}

finally,you run,will done.

Answer 2

Here in swift version for same.

textField.addTarget(self, action: "textFieldDidChange:", forControlEvents: UIControlEvents.EditingChanged)

func textFieldDidChange(textField: UITextField) {

}

Thanks

Answer 3

Swift 3 Version

yourTextField.addTarget(self, action: #selector(YourControllerName.textChanges(_:)), for: UIControlEvents.editingChanged)

And get the changes in here

func textChanges(_ textField: UITextField) {
    let text = textField.text! // your desired text here
    // Now do whatever you want.
}

Hope it helps.

Answer 4

Swift:

yourTextfield.addTarget(self, action: #selector(textFieldDidChange(textField:)), for: .editingChanged)

Then, implement the callback function:

@objc func textFieldDidChange(textField: UITextField){

print("Text changed")

}

Answer 5

[[NSNotificationCenter defaultCenter] addObserver:self 
selector:@selector(didChangeTextViewText:) 
name:UITextFieldTextDidChangeNotification object:nil];



- (void) didChangeTextViewText {
 //do something
}

Answer 6

With closure:

   class TextFieldWithClosure: UITextField {
    var targetAction: (() -> Void)? {
        didSet {
            self.addTarget(self, action: #selector(self.targetSelector), for: .editingChanged)
        }
    }

    func targetSelector() {
        self.targetAction?()
    }
    }

and using

textField.targetAction? = {
 // will fire on text changed
 }