Q:

Enable keyboard return key

I would like to enable the keyboard return key only when some uitextfields are not empty. 
I read this question 
How to disable/enable the return key in a UITextField? 
Is this the only way?  Is it true this could cause Apple to reject the app? 

A:

Following thing will enable/disable return key automatically. 

(BOOL)textFieldShouldBeginEditing:(UITextField *)textField  {
 textfield.enablesReturnKeyAutomatically = YES;

// your code here

  return YES;  }

A:

You can use the textFieldShouldReturn: method to prevent the return key from returning. 
http://developer.apple.com/library/ios/#documentation/uikit/reference/UITextFieldDelegate_Protocol/UITextFieldDelegate/UITextFieldDelegate.html

