Bind NSSegmentedControl to a boolean?

Question

I'm still new to Cocoa Bindings and I haven't found an answer to this question even after looking through the docs. What I want to do is have a segmented control that only has two segments. If the first segment is selected, then a preference in NSUserDefaults should be YES , but if the second segment is selected, then the preference should be NO. This is trivial to do through code:

-(IBAction)segmentSelectionChanged:(id)sender {
    NSInteger selectedSegment = [sender selectedSegment];
    [[NSUserDefaults standardUserDefaults] setBool:(selectedSegment==0)?YES:NO forKey:@"somepref"];
}

but I'd like to do it through bindings (selected index looks promising). Any way to do something like this? Thanks!

Answer 1

I think you've got it already -- binding the control's selectedIndex in IB:

Bind To: Shared User Defaults Controller
Controller Key: values
Key Path: WhateverYouWant

seems to work just fine.

Is the problem that you really need it to be a BOOL? It's just a typedef for signed char anyways. See objc.h, lines 43, 49, and 50:

typedef signed char     BOOL;
// ...
#define YES             (BOOL)1
#define NO              (BOOL)0

You can pull the value back out using integerForKey: and cast it (possibly better because more explicit):

(BOOL)[[NSUserDefaults sharedUserDefaults] integerForKey:@"WhateverYouWant"];

or just continue using boolForKey: and it should work fine.