[Wes]

I have an NSTextField and an NSStepper set up in Interface Builder, and then connected using the takeValue actions. But how do I set it up so that every-time a number is typed into the NSTextField, the value of NSStepper is changed so that when the user "steps" the NSTextField doesn't revert back to the old value of whatever the NSStepper had previously?

[itai195]

I've never used an NSStepper, but I'd guess that you'd want to use the - setIntValue: method in its superclass (NSControl). Not sure if that works, but worth a shot.

[Wes]

It looks like something along those lines should work... can you give me any more details though? I'm still having trouble.

[itai195]

Sure. What you probably want to do is use a delegate for the NSTextField and also connect the delegate to the NSStepper via an outlet (you'll probably use a controller object for all of this). Implement the textDidChange: method in the delegate. That method should call setIntValue: on the NSStepper, passing whatever the current value of the NSTextField is. I can't try this out to check if it works right now, but I can try later tonight if you haven't had time to try it by then.

[Chuckit]

I second that solution. What you need is to update the stepper's value every time the text field is edited, but NSTextField will only send its action after you finish editing. So you'll need to use controlTextDidChange:.

Incidentally, I still find it strange Apple didn't include a simple NSSteppingTextField control.

[Wes]

The whole "delegate" thing still confuses me. So if any of you have time I would appreciate a simple run threw of them as applied to my situation

Thanks for the help.

[itai195]

Have you read this document? It describes some Cocoa design patterns, including delegates. There is also this introduction and you might be able to find some other info at cocoadev.com. If you're confused about how to set a delegate up, you can do it in Interface Builder by control-dragging a connection between your delegate in the instances pane and the NSTextField in your interface.

The delegate in your situation receives a notification from the NSTextField when its value changes and responds to that notification by changing the value of the NSStepper. The delegate is essentially an event handler in this scenario.

[Wes]

I understand those documents (albeit vaguely), however I still don't know what is meant by...

I second that solution. What you need is to update the stepper's value every time the text field is edited, but NSTextField will only send its action after you finish editing. So you'll need to use controlTextDidChange:.

Do I make an action "controlTextDidChange" from my TextField to the controller class that updates the value of the stepper? Will it automatically understand what I'm talking about?

[itai195]

Originally posted by Wes:
I understand those documents (albeit vaguely), however I still don't know what is meant by...


Do I make an action "controlTextDidChange" from my TextField to the controller class that updates the value of the stepper? Will it automatically understand what I'm talking about?

You need to connect the controller instance to the text field's delegate outlet in IB, and then implement that method as described above. The method will automatically be called when the value in the text field changes, and the body of the code (which you must implement) will update the value of the NSStepper.

[Wes]

I got it working with notifications in a fairly round-about way...

But if you could spare some more time for me I have another question. I want to perform a function on window loading. I have made my controller class the delegate of my window and added windowDidLoad, but that doesn't seem to want to work... any ideas?

Edit-

One more question, I tried calling ((NSTextField)field).setPlaceholderString("String" ) and it gave me a "cannot resolve symbol symbol : method setPlaceholderString (java.lang.String)". I was under the impression that NSTextField implemented all the methods of NSTextFieldCell (which contains setPlaceholderString()). ?

[bewebste]

Using the text field's delegate is one way to do it, but I usually just use the action of the text field instead. The main difference is that the delegate will get called each time the user presses a key in the text field, whereas the action only gets called when the user finished editing (i.e. presses return or tab to exit the field).

Here's the way I usually handle a text field/stepper combo:

1. Create two outlets and hook them up to the text field and stepper. Let's say the outlets are called myTextField and myStepper.
2. Add an action to your controller object (we'll call it changeMyValue:) and then hook up both the stepper and the text field to that same action.
3. The action method then looks like this:

Code:
- (IBAction)changeMyValue:(id)sender
{
   int theValue = [sender intValue];
   [myStepper setIntValue:theValue];
   [myTextField setIntValue:theValue];
}

Since the sender variable will hold whichever control it was that the user changed, you get the new value from the correct control, and then just put that value back into both controls, ensuring that they stay synchronized.

As for the windowDidLoad method, that is a method specific to the NSWindowController class, so it will only get called if you're loading the window through one of them. Otherwise, you should implement awakeFromNib to implement stuff that should happen after the nib file has been fully loaded.