Question

I am new to the ios development, I am just trying to create a simple application for calculations, So for that i have used to textboxes and i want to allow only the numeric values for these. i have already set the keyboard property to numeric pad. Now i want to do it programmatically for that i found the following function from checks for the String contains Numeric value only

+(BOOL) checkforNumeric:(NSString*) str 
{ 
NSString *strMatchstring=@"\\b([0-9%_.+\\-]+)\\b"; 
NSPredicate *textpredicate=[NSPredicate predicateWithFormat:@"SELF MATCHES %@", strMatchstring]; 
if(![textpredicate evaluateWithObject:str]) 
{ 
//////NSLog(@"Invalid email address found"); 
UIAlertView *objAlert = [[UIAlertView alloc] initWithTitle:APP_NAME message:@"please enter valid text." delegate:nil cancelButtonTitle:nil otherButtonTitles:@"Close",nil]; 
[objAlert show]; 
[objAlert release]; 
return FALSE; 
} 
return TRUE; 
} 

Now i want to call it on button’s click, i have tried some ways but it always shows error.
Please help me how can i utilize this function in button’s click.

My Actual code of button is:

-(IBAction)button{
if (firstValue.text.length>0 && secondvalue.text.length>0) {

    label.text=  [ [NSString alloc] initWithFormat:@"Result is:  %.2f", ([firstValue.text floatValue]) * ([secondvalue.text floatValue])];

}
else if (firstValue.text.length==0 && secondvalue.text.length==0){
    //label.text=    @"please enter the values.";
    UIAlertView  *alert = [[UIAlertView alloc] initWithTitle:@"Alert" message:@"Please Enetr First Value and second value." delegate:nil cancelButtonTitle:@"Ok" otherButtonTitles:nil];
    [alert show];
    [alert release];
}else if (firstValue.text.length==0) {
    //label.text=    @"please enter the first values.";
    UIAlertView *alert=[[UIAlertView alloc] initWithTitle:@"Alert" message:@"Please Enter First Value" delegate:nil cancelButtonTitle:@"Ok" otherButtonTitles:nil];
    [alert show];
    [alert release];
}else if (secondvalue.text.length==0) {
    //label.text=    @"please enter the second values.";
    UIAlertView *alert=[[UIAlertView alloc] initWithTitle:@"Alert" message:@"Please Eneter Second Value" delegate:nil cancelButtonTitle:@"Ok" otherButtonTitles:nil];
    [alert show];
    [alert release];
}
}

Please help me.

I have tried the following ways for this:

BOOL *test= checkforNumeric(firstValue.text);

Answer 1

call your Method like this

BOOL isValidString_withNoNumbers = [self checkforNumeric: firstValue.text];
if(isValidString_withNoNumbers)
{
     //your code
}

and also you should change the method to instance method

so it should be

-(BOOL) checkforNumeric:(NSString*) str // - for instance method //+ for class methods