How to check the textFiled input string when user

问题:

I have a problem.
I have four textfields, but I don't know how to check the textfield that input String.

• nameField doesn't over 10 strings
• ageField check whether is number or not
• sexField check male or female

This is my code:

- (IBAction)addComment:(id)sender {

    UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"Commend" message:nil preferredStyle:UIAlertControllerStyleAlert];

    [alertController addTextFieldWithConfigurationHandler:^(UITextField *textField) {
        textField.placeholder = @"Please input your name:";
    }];
    [alertController addTextFieldWithConfigurationHandler:^(UITextField *textField) {
        textField.placeholder = @"Please input your age:";
    }];
    [alertController addTextFieldWithConfigurationHandler:^(UITextField *textField) {
        textField.placeholder = @"Please input your sex:";
    }];
    [alertController addTextFieldWithConfigurationHandler:^(UITextField *textField) {
        textField.placeholder = @"Please input your commend:";
    }];

    UIAlertAction *sendAction = [UIAlertAction actionWithTitle:@"send" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {

        UITextField *nameField = alertController.textFields[0];
        UITextField *ageField = alertController.textFields[1];
        UITextField *sexField = alertController.textFields[2];
        UITextField *commentField = alertController.textFields[3];


        UIAlertController *successAlertController = [UIAlertController alertControllerWithTitle:@"Alert" message:@"Success" preferredStyle:UIAlertControllerStyleAlert];
        UIAlertAction *okAction = [UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {

            [self.navigationController popViewControllerAnimated:YES];

        }];
        [successAlertController addAction:okAction];
        [self presentViewController:successAlertController animated:YES completion:nil];


    }];

    [alertController addAction:sendAction];
    [self presentViewController:alertController animated:YES completion:nil];

}

Thanks!

回答1:

Follow below steps, may it help:

1. Set delegate and tag to UIAlertController textfields.

2. Now use UITextField delegate method shouldChangeCharactersInRange to validate text while typing OR use textFieldDidEndEditing to check after textfield end editing . Check using it's tag to differentiate between textFields.

Like,

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

if(textField.tag==TxtNameTag){

   //Validate Name textField
}
//Same way for other textFields


    return YES; 
}

OR Use textFieldDidEndEditing to validate while textField end editing.

回答2:

Try textField delegate method shouldChangeCharactersInRange

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


// here you can get your textfield text and perform an action according to your choice while user is inputting.

    return YES; //this make iOS not to perform any action
}

回答3:

Have a look on textField delegate method shouldChangeCharactersInRange. It will get called every time when you press any character in textfield.

回答4:

You can implement the UITextFieldDelegate:

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

Doc

回答5:

plz use the the tag propertiy of textfield

UITextField *nameField = alertController.textFields[0];
    UITextField *ageField = alertController.textFields[1];
    UITextField *sexField = alertController.textFields[2];
    UITextField *commentField = alertController.textFields[3];


  nameField.tag = 1;
  ageField.tag = 2;

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

    // identify with tag

   if(textField.tag == 1)
   {

   }
    else if (textField.tag == 2)
  {

  }
        return YES; 
    }

回答6:

1.Set Delegate for UITextField.

2.Add tag.

UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"Commend" message:nil preferredStyle:UIAlertControllerStyleAlert];

        [alertController addTextFieldWithConfigurationHandler:^(UITextField *textField) {
            textField.placeholder = @"Please input your name:";
            textField.tag=100;
        }];   

3. The below Delegate will be called for every char entered.

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

    if(textField.tag==100){

       //Validate Name textField
    }
    else if(textField.tag==101){
    //nextfield textFields
    }
        return YES; 
 }

回答7:

<your text field>.delegate = self
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
   //name text field validation
   if textField == nameField{
        if textField.text.characters.count < 10 {
           return true
        }
   }

   //age text field validation
   if textField == ageField{
        if Int(textField.text) != nil {
           return true
        }
   }

   //sex text field validation
   if textField == sexField{
        if textField.text + replacementString == "male" {
              <he is a man>
        }else if textField.text + replacementString == "female"{
              <she is a woman>
        }

        return true

   }



   return false
}

回答8:

[textField addTarget:self action:@selector(textDidChanged:) forControlEvents:UIControlEventEditingChanged];

like this copy also can check

回答9:

Try using JSInputField with modalViewController

JSInputField *inputField = [[JSInputField alloc] initWithFrame:CGRectMake(10, 100, 300, 50)];
[self.view addSubview:inputField];
[inputField setPlaceholder:@"Please input your name"];
[inputField setRoundedCorners:UIRectCornerAllCorners];
[inputField addValidationRule:JSCreateRuleNotNullValue]; //This will validate field for null value. It will show error if field is empty.
[inputField addValidationRule:JSCreateRuleLength(10)];  //This will validate field for string of length equal to or less than 10.


JSInputField *inputField = [[JSInputField alloc] initWithFrame:CGRectMake(10, 100, 300, 50)];
[self.view addSubview:inputField];
[inputField setPlaceholder:@"Please input your age"];
[inputField setRoundedCorners:UIRectCornerAllCorners];
[inputField addValidationRule:JSCreateRuleNotNullValue]; //This will validate field for null value. It will show error if field is empty.
[inputField addValidationRule:JSCreateRuleNumeric(0)];  //This will validate field for numeric values and restrict to enter value upto 0 decimal places.