06-10-2011, 11:20 AM

Hi all, this is my first post! I've started learning obj-c/cocoa for mac few days ago and I've decided to port a small project in Qt (a minefield game) to Mac/Cocoa.

I have some problems in writing the controller. I have to manage a group of buttons that represent my minefield. I have no problems with actions: from what i understand i just have to link a button to the action from the interface builder and then simply copy/paste the resulting button.

But how can I manage the outlets? In Qt there is an object called QButtonGroup that lets me create a matrix of buttons and simply link them to the code. Is there something similar in Cocoa/ObjC? Can someone kindly point me in the right direction?


I've attached the project, just in case..

06-12-2011, 06:36 PM

I've done something similar. Maybe this will be helpful to you.

I didn't use buttons. Instead I used NSImageView, NSImage and NSView. I subclassed NSImageView to hold and handle NSImages I was flipping between. Each square in a grid was an instance of my NSImageView subclass. When clicked on, captured via the mouseDown event, I called a delegate which is my game engine. My engine was responsible for a few things including messaging back to the square to perform an appropriate action.

In my game, the grid was dynamically created. I had a background view which is a fixed size but the active squares on it could be 7 or 8 across by 8 or 9 down. That background view was used to group the squares. This was a port of something I'm doing on iOS so more squares didn't make sense. The dynamic creation means that I did not use Interface Builder to build the grid of squares, and I could create any size grid. You can change the size of the grouping view dynamically if needed. I placed that in IB as a starting representation and linked it to an outlet for possible action on it.

Since my NSImageView is added as a subview to the group view, there is no need to keep track of them in an NSArray. The group view effectively acts as an array. Also, because of the dynamic nature, I don't need outlet ivars.

If you need to know which square has been clicked on, then perhaps use the tag property. You would set that as you create each square. Read the documentation on how to do that. You can set those in IB if you build your squares in it.

When you setup a button (or other interface type) to call an action method, you should be using a method that accepts the sender id. When the action is called, you can use that id to pass messages back to the sender. That method pattern would look like this;

- (IBAction) myAction: (id) sender;

So you could do have like this;

- (IBAction) myAction: (id) sender;
{
   NSInteger tag = [sender tag]; // tag should be unique to id specific sender
   if (tag == 0) [sender doSomething];
   else if (tag == 99) [sender doSomethingElse];
}

P.S. I haven't looked at your code. I tend not to download whole projects for questions. When you have something very specific then you should post the snippet of code.

06-13-2011, 07:34 AM

Well, first of all - thank you for the reply

I suppose that I didn't explain my problem well though. What I want to do is change the image (or the label, whatever) of my matrix of buttons. So:

- The player clicks a button
- The controller gets the button's tag and transforms it in x and y coordinates
- The controller calls a recursive method of the model, passing x and y, where the cells are "uncovered"
- The controller now should write the number of bombs on the covered buttons. My problem is: how can I keep track of the buttons? From what I've understood, the only way to achieve this is to generate the matrix from the code. Or, perhaps, is there a way to ask buttons something like "who has this tag?"

To be honest I'm a little bit confised :S

P.S. I haven't looked at your code. I tend not to download whole projects for questions. When you have something very specific then you should post the snippet of code.

Thank you for the advice

06-13-2011, 01:10 PM

It seems that I've found a partial solution - I've selected a button in IB, then I've selected Layout -> Embed Objects In -> Matrix and then I've just option-dragged the resize grip of the button to create my matrix. However, I can't understand how to control it from the controller

06-13-2011, 02:03 PM

Ok I figured it out - I just had to declare an NSMatrix* in the controller and drag connections from and to the matrix (that was easy enough ). Now I can simply manage the button matrix from my code. Problem solved

06-13-2011, 04:01 PM

Good to hear you found a better solution. I had forgotten that NSMatrix existed.