Question

I have a class inherited from UITableViewController and this is also the root class. This tableView contains three custom UITableViewCells (loaded from NIB file and not subclassed) and each UITableViewCell has one UITextField. Now when I implement delegate method

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

I don’t recieve any event. This function never gets fired, I tried implementating other delegate methods too but none of them fires. How to fire these delegate methods?

I also want to override canPerformAction:sender: function for these UITextFields (Which are part of UITableViewCell);
How to do this?

Answer 1

The textField:shouldChangeCharactersInRange:replacementString: method is part of the UITextFieldDelegate protocol, so you have to set a delegate for these UITextFields.

For example, if you were creating the UITextFields in your table view contoller code, and assuming the method was implemented in the same contoller, you could do this:

UITextField *textField = [[UITextField alloc] initWithFrame:CGRectMake(x,y,w,h)];
[textField setDelegate:self];

However, you say you’re loading the UITableViewCells from XIB files. You have to somehow access the UITextFields from inside the code and call the setDelegate: method on them. You can do this by using UIView‘s subviews property. For example:

UIViewController *controller = [[UIViewController alloc] initWithNibName:@"foo" bundle:nil];
UITextField *textField = (UITextField *)[[controller.view subviews] objectAtIndex:0];

Though creating the UITextFields in the code is much easier and more elegant, IMHO.

As for overriding the canPerformAction:sender: method, you’ll have to subclass UITextField for that.