Question

In my specific case, how do I identify or know which UITextField is being referenced in shouldChangeCharactersInRange method?

I know the parameter (UITextField*)textField contains the object being referenced, but how do I compare to identify which one it is?

Answer 1

1. If you create your interface using IB then you can create IBOutlet in your controller for each UI element, connect then in IB and later compare textField parameters with them:

   //header
   IBOutlet UITextField* nameField;
   IBOutlet UITextField* addressField;
   
   //Implementation
   ...
   if (textField == nameField){
   }
   if (textField == addressField){
   }
   

2 In IB you can also assign a unique tag value for each UITextField (available for each UIView subclasses) and compare tag values:

    #define nameTag 10
    #define addressTag 11

    //Implementation
    ...
    if (textField.tag == nameTag){
    }
    if (textField.tag == addressTag){
    }