how to validate textfield that allows . only once with in the textfield - iphone

Question

I have 4 text fields in my application.
I validate my textfields as textfield allow 0,1,...9 and .,for that i write code as fallows
- (IBAction) textfield:(id)sender {
if ([textfield.text length] > 0) {
if ([textfield.text length] > 10){
textfield.text = [textfield.text substringWithRange:NSMakeRange(0, 10)];
}
else {
//retrieve last character input from texfield
int I01 = [homevalue.text length];
int Char01 = [homevalue.text characterAtIndex:I01-1];
//check and accept input if last character is a number from 0 to 9
if ( (Char01 < 46) || (Char01 > 57) || (Char01 == 47) ) {
if (I01 == 1) {
textfield.text = nil;
}
else {
textfield.text = [homevalue.text substringWithRange:NSMakeRange(0, I01-1)];
}
}
}
}
}
It works fine, Now i need to validate that . allows only once with in the textfield.
eg: 123.45
According to my code if i place again . it is allowed.
eg:123.45.678
But it wont allowed once i place . ,that textfield wont allowed.
ed:123.45678.
How can i done this,
can any one pls help me.
Thank u in advance.

Answer 1

Try this predicate for texts that start with a number like "23.67"
NSString *decimalRegex = #"[0-9]+([.]([0-9]+)?)?"; // #"[0-9]+[.][0-9]+";
NSPredicate *decimalTest = [NSPredicate predicateWithFormat:#"SELF MATCHES %#", decimalRegex];
BOOL isValidDecimal = [decimalTest evaluateWithObject:[textField text]];
If you want to allow "." at the fist place like ".95" use the following regex,
NSString *decimalRegex = #"[0-9]*([.]([0-9]+)?)?"; //#"[0-9]*[.][0-9]+";
Your code should look like this,
- (IBAction)textfield:(id)sender {
int textLength = [[textfield text] length];
if (textLength > 0) {
NSString *decimalRegex = #"[0-9]+([.]([0-9]+)?)?"; //#"[0-9]+[.][0-9]+";
NSPredicate *decimalTest = [NSPredicate predicateWithFormat:#"SELF MATCHES %#", decimalRegex];
BOOL isValidDecimal = [decimalTest evaluateWithObject:[textField text]];
if (!isValidDecimal) {
NSString *text = [[textField text] substringToIndex:textLength - 1];
[textfield setText:text]
}
}
}
I guess this should work! Give it a try!

Answer 2

Well you can use this method
- (NSRange)rangeOfCharacterFromSet:(NSCharacterSet *)aSet options:(NSStringCompareOptions)mask range:(NSRange)aRange
on textfield.text as its a NSString only