UITextField, автоматически переходит к следующему после 1 символа

Ответ 1

Я пришел к решению, изменив код, который я нашел здесь: http://www.thepensiveprogrammer.com/2010/03/customizing-uitextfield-formatting-for.html

Сначала установите ваш контроллер представления как делегат текстовых полей.

Затем сделайте что-то вроде этого:

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{   
    BOOL shouldProcess = NO; //default to reject
    BOOL shouldMoveToNextField = NO; //default to remaining on the current field

    int insertStringLength = [string length];
    if(insertStringLength == 0){ //backspace
        shouldProcess = YES; //Process if the backspace character was pressed
    }
    else {
        if([[textField text] length] == 0) {
            shouldProcess = YES; //Process if there is only 1 character right now
        }
    }

    //here we deal with the UITextField on our own
    if(shouldProcess){
        //grab a mutable copy of what currently in the UITextField
        NSMutableString* mstring = [[textField text] mutableCopy];
        if([mstring length] == 0){
            //nothing in the field yet so append the replacement string
            [mstring appendString:string];

            shouldMoveToNextField = YES;
        }
        else{
            //adding a char or deleting?
            if(insertStringLength > 0){
                [mstring insertString:string atIndex:range.location];
            }
            else {
                //delete case - the length of replacement string is zero for a delete
                [mstring deleteCharactersInRange:range];
            }
        }

        //set the text now
        [textField setText:mstring];

        [mstring release];

        if (shouldMoveToNextField) {
            //
            //MOVE TO NEXT INPUT FIELD HERE
            //
        }
    }

    //always return no since we are manually changing the text field
    return NO;
}

Ответ 2

Я знаю, что это очень старый вопрос, но здесь мой подход для предоставления единственного числового значения только для четырех UITextFields и автоматического "табуляции" на следующий (pin1-pin4 каждый представляет цифру PIN-кода lol и сохраняются как свойства):

-(BOOL)textFieldShouldReturn:(UITextField*)textField;
{
    if (textField == pin1)
    {
        [pin2 becomeFirstResponder];
    }
    else if (textField == pin2)
    {
        [pin3 becomeFirstResponder];
    }
    else if (textField == pin3)
    {
        [pin4 becomeFirstResponder];
    }

    return NO;
}

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    // This allows numeric text only, but also backspace for deletes
    if (string.length > 0 && ![[NSScanner scannerWithString:string] scanInt:NULL])
        return NO;

    NSUInteger oldLength = [textField.text length];
    NSUInteger replacementLength = [string length];
    NSUInteger rangeLength = range.length;

    NSUInteger newLength = oldLength - rangeLength + replacementLength;

    // This 'tabs' to next field when entering digits
    if (newLength == 1) {
        if (textField == pin1)
        {
            [self performSelector:@selector(setNextResponder:) withObject:pin2 afterDelay:0.2];
        }
        else if (textField == pin2)
        {
            [self performSelector:@selector(setNextResponder:) withObject:pin3 afterDelay:0.2];
        }
        else if (textField == pin3)
        {
            [self performSelector:@selector(setNextResponder:) withObject:pin4 afterDelay:0.2];
        }
    }
    //this goes to previous field as you backspace through them, so you don't have to tap into them individually
    else if (oldLength > 0 && newLength == 0) {
        if (textField == pin4)
        {
            [self performSelector:@selector(setNextResponder:) withObject:pin3 afterDelay:0.1];
        }
        else if (textField == pin3)
        {
            [self performSelector:@selector(setNextResponder:) withObject:pin2 afterDelay:0.1];
        }
        else if (textField == pin2)
        {
            [self performSelector:@selector(setNextResponder:) withObject:pin1 afterDelay:0.1];
        }
    }

    return newLength <= 1;
}

- (void)setNextResponder:(UITextField *)nextResponder
{
    [nextResponder becomeFirstResponder];
}

Ответ 3

ОБНОВЛЕННЫЙ КОД ДЛЯ SWIFT 3

@IBOutlet weak var tf1: UITextField!
@IBOutlet weak var tf2: UITextField!
@IBOutlet weak var tf3: UITextField!
@IBOutlet weak var tf4: UITextField!
override func viewDidLoad() {
    super.viewDidLoad()
    tf1.delegate = self
    tf2.delegate = self
    tf3.delegate = self
    tf4.delegate = self


    tf1.addTarget(self, action: #selector(self.textFieldDidChange(textField:)), for: UIControlEvents.editingChanged)
    tf2.addTarget(self, action: #selector(self.textFieldDidChange(textField:)), for: UIControlEvents.editingChanged)
    tf3.addTarget(self, action: #selector(self.textFieldDidChange(textField:)), for: UIControlEvents.editingChanged)
    tf4.addTarget(self, action: #selector(self.textFieldDidChange(textField:)), for: UIControlEvents.editingChanged)

}
override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(true)
    tf1.becomeFirstResponder()

}
func textFieldDidChange(textField: UITextField){

    let text = textField.text

    if text?.utf16.count==1{
        switch textField{
        case tf1:
            tf2.becomeFirstResponder()
        case tf2:
            tf3.becomeFirstResponder()
        case tf3:
            tf4.becomeFirstResponder()
        case tf4:
            tf4.resignFirstResponder()
        default:
            break
        }
    }else{

    }
}

Ответ 4

Хотя это старый вопрос, я просто пересек его, и я пришел с более простым решением. предполагая, что мы делаем это для кода прохода, поэтому максимальная длина каждой ячейки (UITextField) равна char.

- (BOOL) textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{
    if (![string isEqualToString:@""]) {
        textField.text = string;
        if ([textField isEqual:self.txtField1]) {
            [self.txtField2 becomeFirstResponder];
        }else if ([textField isEqual:self.txtField2]){
            [self.txtField3 becomeFirstResponder];
        }else if ([textField isEqual:self.txtField3]){
            [self.txtField4 becomeFirstResponder];
        }else{
            [textField resignFirstResponder];
        }
        return NO;
    }
    return YES;
}

-(BOOL)textFieldShouldBeginEditing:(UITextField *)textField{
    if (textField.text.length > 0) {
        textField.text = @"";
    }
    return YES;
}