CODEWITHSUNDEEP
iphoneiosipadnsstringuitextfield
A for Alpha
A for Alpha

Reputation: 2912

How to know if a UITextField in iOS has blank spaces

I have a UITextField where user can enter a name and save it. But, user should not be allowed to enter blank spaces in the textFiled.

1 - How can I find out,if user has entered two blank spaces or complete blank spaces in the textFiled

2 - How can i know if the textFiled is filled only with blank spaces

edit - It is invalid to enter only white spaces(blank spaces)

Upvotes: 29

Views: 33273

Answers (9)

Ronak Patel
Ronak Patel

Reputation: 629

In Swift,

if you want to restrict the user, you can use contains()

For Example,

if userTextField.text!.contains(" "){
//your code here.....
}

Upvotes: 1

Pankaj Gaikar
Pankaj Gaikar

Reputation: 2483

Heres Swift 3 version

let whitespaceSet = NSCharacterSet.whitespaces
let range = string.rangeOfCharacter(from: whitespaceSet)
if let _ = range {
    return false
}
else {
    return true
}

Upvotes: 1

DZenBot
DZenBot

Reputation: 4878

@Hanon's answer is the pretty neat, but what I needed was to allow at least 1 white space, so based on Hanon's solution I made this one:

I declared a local variable called whitespaceCount to keep the counts of the white spaces. Hope this helps anybody!

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range     replacementString:(NSString *)string 
{ 
    NSCharacterSet *whitespaceSet = [NSCharacterSet whitespaceCharacterSet];

    if ([string rangeOfCharacterFromSet:whitespaceSet].location != NSNotFound) 
    {
        whitespaceCount++;
        if (whitespaceCount > 1) 
        {
            return NO;
        }
    }
    else 
    {
        whitespaceCount = 0;
        return YES;
    }
}

Upvotes: 0

Narayana Rao Routhu
Narayana Rao Routhu

Reputation: 6323

Use following lines of code 

NSString *str_test = @"Example ";
NSCharacterSet *whitespaceSet = [NSCharacterSet whitespaceCharacterSet];
if([str_test rangeOfCharacterFromSet:whitespaceSet].location!=NSNotFound)
{
    NSLog(@"Found");
}

if you want to restrict user use below code

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    if([string isEqualToString:@" "])
    {
        return NO
    }
    else
    {
        return YES
    }
}

Upvotes: 6

Arnlee Vizcayno
Arnlee Vizcayno

Reputation: 2426

Here's what I did using stringByReplacingOccurrencesOfString.

- (BOOL)validateFields
 {
      NSString *temp = [textField.text stringByReplacingOccurrencesOfString:@" "
                                                          withString:@""
                                                             options:NSLiteralSearch
                                                               range:NSMakeRange(0, textField.text.length)];

      if ([temp length] == 0) {
          // Alert view with message @"Please enter something."
          return NO;
      }
 }

Upvotes: 0

Yevhen Dubinin
Yevhen Dubinin

Reputation: 4733

UPD: Swift 2.0 Support

func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
    let whitespaceSet = NSCharacterSet.whitespaceCharacterSet()
    let range = string.rangeOfCharacterFromSet(whitespaceSet)
    if let _ = range {
        return false
    }
    else {
        return true
    }
}

Upvotes: 3

DreamWatcher
DreamWatcher

Reputation: 399

I had a same condition not allowing user to input blank field

Here is my code and check statement

- (IBAction)acceptButtonClicked:(UIButton *)sender {
if ([self textFieldBlankorNot:fullNametext]) {
        fullNametext.text=@"na";
    }
// saving value to dictionary and sending to server

}

-(BOOL)textFieldBlankorNot:(UITextField *)textfield{
    NSString *rawString = [textfield text];
    NSCharacterSet *whitespace = [NSCharacterSet whitespaceAndNewlineCharacterSet];
    NSString *trimmed = [rawString stringByTrimmingCharactersInSet:whitespace];
    if ([trimmed length] == 0)
        return YES;
    else
        return NO;
}

Upvotes: 1

DarkDust
DarkDust

Reputation: 92335

You can "trim" the text, that is remove all the whitespace at the start and end. If all that's left is an empty string, then only whitespace (or nothing) was entered.

NSString *rawString = [textField text];
NSCharacterSet *whitespace = [NSCharacterSet whitespaceAndNewlineCharacterSet];
NSString *trimmed = [rawString stringByTrimmingCharactersInSet:whitespace];
if ([trimmed length] == 0) {
    // Text was empty or only whitespace.
}

If you want to check whether there is any whitespace (anywhere in the text), you can do it like this:

NSRange range = [rawString rangeOfCharacterFromSet:whitespace];
if (range.location != NSNotFound) {
    // There is whitespace.
}

If you want to prevent the user from entering whitespace at all, see @Hanon's solution.

Upvotes: 97

Hanon
Hanon

Reputation: 3927

if you really want to 'restrict' user from entering white space

you can implement the following method in UITextFieldDelegate

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

    NSString *resultingString = [textField.text stringByReplacingCharactersInRange: range withString: string];
    NSCharacterSet *whitespaceSet = [NSCharacterSet whitespaceCharacterSet];
    if  ([resultingString rangeOfCharacterFromSet:whitespaceSet].location == NSNotFound)      {
        return YES;
    }  else  {
        return NO;
    }
 }

If user enter space in the field, there is no change in the current text

Upvotes: 13

Related Questions