CODEWITHSUNDEEP
iosnumbersswift3formatternsnumberformatter
AppsDev
AppsDev

Reputation: 12509

Best way to validate a number input in iOS?

I have a UITextField where the user should type a float number. I want to check that such number has a certain format I receive, for instance "dddd.dd", where "d" is a digit. The format could change at any moment, since I receive it as input as well, so for example I may want to check at another moment that "," character is used for decimals, to say another example.

Taking into account that the text you read from the UITextField is of String type (optional), what should be the best way to accomplish this?

Upvotes: 0

Views: 391

Answers (1)

Saheb Roy
Saheb Roy

Reputation: 5967

Try this

in viewDidLoad or assign delegate to the textfield to self

-(void)viewDidLoad{
   self.txtFieldName.delegate = self;
}

Now implement this delegate method - 

 -(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    if(textField == self.txtFieldName)
    {
        NSCharacterSet *invalidCharSet = [[NSCharacterSet characterSetWithCharactersInString:@"01234567989."] invertedSet];
        NSString *filtered = [[string componentsSeparatedByCharactersInSet:invalidCharSet] componentsJoinedByString:@""];
        return [string isEqualToString:filtered];
    }
    else
        return YES;
}

This will enable yout textfield to only take numbers from 0-9 and .(decimal).

Upvotes: 1

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