Enable/Disable UIButton 取决于 UITextField 中文本的长度

Question

我有一个包含 3 个静态单元格的 tableViewController。每个单元格都有一个 UITextField。

我正在尝试计算每个文本字段中的文本长度以启用或禁用按钮。

为此，我使用了 textField 委托方法

-textField:shouldChangeCharactersInRange:replacementString:

但我无法获得正确的值，例如在密码字段中，我想在长度超过 6 个字母时启用按钮，而在长度小于 6 个字母时禁用按钮。

目前我无法获得正确的长度，例如要禁用密码字段中的按钮我需要达到 3 个字符，否则它不会被禁用。这对我来说是错误的，因为当字符少于 6 个时按钮必须禁用。

这是我的代码，你能解释一下我错在哪里吗？

-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {

     if ([self.passwordTextField.text length] >6 && [self.nameTextField.text length] >2 && [self.emailTextField.text length] >2) [self.stepCompleted setEnabled:YES];

     else if ([self.passwordTextField.text length]  <6 || [self.nameTextField.text length] <2 || [self.emailTextField.text length] <2) [self.stepCompleted setEnabled:NO];


    return YES;
}

Answer 1

首先您需要检查 textfield == self.passwordTextField 或任何其他文本字段是否包含，然后应用您的条件。

-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    if (string==nil || [string isEqualToString:@""] || [string isKindOfClass:[NSNull class]] || string.length < 1)
    {
        if([self.nameTextField.text length] < 2 || [self.emailTextField.text length] < 2 || [self.passwordTextField.text length] < 6)
        {
            [self.stepCompleted setEnabled:NO];
        }
    }
    else if(textField == self.passwordTextField && [self.passwordTextField.text length] > 6)
    {
        if([self.nameTextField.text length] > 2 && [self.emailTextField.text length] > 2)
        {
            [self.stepCompleted setEnabled:YES];
        }
        else
        {
            [self.stepCompleted setEnabled:NO];
        }
    }
    else if(textField == self.nameTextField && [self.nameTextField.text length] > 2)
    {
        if([self.passwordTextField.text length] > 6 && [self.emailTextField.text length] > 2)
        {
            [self.stepCompleted setEnabled:YES];
        }
        else
        {
            [self.stepCompleted setEnabled:NO];
        }
    }
    else if(textField == self.emailTextField && [self.emailTextField.text length] > 2)
    {
        if([self.nameTextField.text length] > 2 && [self.passwordTextField.text length] > 6)
        {
            [self.stepCompleted setEnabled:YES];
        }
        else
        {
            [self.stepCompleted setEnabled:NO];
        }
    }
    return YES;
}

Answer 2

您好，请找到解决此问题的方法.. 如果我们需要建立多个 UITextField 中使用的最小字符数，我们可以为我们感兴趣的文本字段建立一个最小限制，并控制方法中剩余文本字段的行为...

Es.. 我们有 3 个 UITextField 姓名 - 电子邮件 - 密码

在此示例中，我们希望在文本字段具有最少字符数时启用或禁用按钮

-(BOOL)textFieldShouldClear:(UITextField *)textField {
    [button setEnabled:NO];
    return YES;
}

-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
    // Otteniamo il numero di caratteri corretti
    NSString *characters = [textField.text stringByReplacingCharactersInRange:range withString:string];

    int minimumCharacter = 2;
    int minimumCharacterForPassoword = 6;

     // Identifichiamo la textField Generica con la textField che andremo ad utilizzare inoltre aggiungiamo anche il numero di caratteri MINIMI che vogliamo utilizzare per attivare il bottone Continua e quindi consentire all'utente di proseguire con la registrazione, altrimenti, se non tutti i requisiti delle textField vengono soddisfatti disabilitiamo il pulsante Continua fino a quando tutti campi non saranno completati

    // NAME
    if (textField == self.firstNameTextField) {
        if  (characters.length >= minimumCharacter) {
            if ((self.passwordTextField.text.length +1) > minimumCharacterForPassoword && (self.emailTextField.text.length +1) > minimumCharacter) [_stepCompletedButton setEnabled:YES];
            else [_stepCompletedButton setEnabled:NO];
        }
        else [_stepCompletedButton setEnabled:NO];
    }

    // EMAIL
    if (textField == self.emailTextField) {
        if  (characters.length >= minimumCharacter) {
            if ((self.passwordTextField.text.length +1) > minimumCharacterForPassoword && (self.firstNameTextField.text.length +1) > minimumCharacter) [_stepCompletedButton setEnabled:YES];
            else [_stepCompletedButton setEnabled:NO];
        }
        else [_stepCompletedButton setEnabled:NO];
    }

    // PASSWORD
    if (textField == self.passwordTextField) {
        if  (characters.length >= minimumCharacterForPassoword) {
            if ((self.firstNameTextField.text.length +1) > minimumCharacter && (self.emailTextField.text.length +1) > minimumCharacter) [_stepCompletedButton setEnabled:YES];
            else [_stepCompletedButton setEnabled:NO];
        }
        else [_stepCompletedButton setEnabled:NO];
    }

    return YES;
}

Enable/Disable UIButton 取决于 UITextField 中文本的长度

Enable/Disable UIButton depends on length of text in UITextField

xcode

objective-c

uitableview

uitextfield

ios