NSMatrix of buttons and Bind issue

This is my situation:

• a NSMatrix (in radio mode) that contains 4 buttons

• An object with properties "top","left","right","bottom" and the relative objectController.

• each button has state bind to one of 开发者_JAVA技巧the objectController key (top,left,right,bottom).

Radio mode makes me sure that only one button at once has state = on, my problem is that when i select a button the object property chained to the objcet controller goes to 1, but the previous one selected (now with state = off) doesn't go to 0 (the buttons view works correctly and only 1 button is active at time).

How can i obtain a on/off effect also on the bind object?

Instead of binding each button, you should bind the selectedIndex binding of the NSMatrix itself to a property in your model.

You'll need to change the way you store the selected edge in your code by using a single property:

typedef enum {
    TopEdge = 0,
    RightEdge,
    BottomEdge,
    LeftEdge
} Edge;

@property Edge currentEdge;

This will allow you to keep track of the currently selected index.