LLHotKeyRecorder works very similarly to NSNotificationCenter. Following is a simple example of how to add (and remove) and observer for a given hot key.

- (void)setup
{
	LLHotKey *hotKey = [LLHotKey hotKeyWithKeyCode:kVK_ANSI_K modifierFlags:(NSControlKeyMask | NSCommandKeyMask)];
	[[LLHotKeyCenter defaultCenter] addObserver:self selector:@selector(hotKeyTriggered):) hotKey:hotKey];
}

- (void)hotKeyTriggered:(LLHotKey *)hotKey
{
	[[LLHotKeyCenter defaultCenter] removeObserver:self hotKey:hotKey];
}

LLHotKeyRecorder comes with an NSControl subclass that can be used to record a hot key. It is very simple to use and behaves just like a normal NSControl. You can add a target and action and it will be notified every time the hotKeyValue changed.

LLHotKeyRecorder also comes with a couple of convenience methods so that storing and retrieving a LLHotKey from the user defaults is easy. Here is a simple example.

LLHotKey *hotKey = [LLHotKey hotKeyWithKeyCode:kVK_ANSI_B modifierFlags:(NSControlKeyMask | NSCommandKeyMask)];
[[NSUserDefaults standardUserDefaults] setHotKey:hotKey forKey:@"HotKey"];

LLHotKey *restoredHotKey = [[NSUserDefaults standardUserDefaults] hotKeyForKey:@"HotKey"];

You can simply drag the LLHotKeyRecorder project as a subproject in your application main project. You will then have to add the framework as a Target Dependency in the Build Phases, link to the framework by adding it to the Link Binary with Libraries in the target Build Phases. Finally you will have to copy the framework to the final product by adding a custom copy Build Phase to the Frameworks directory.

The framework uses @rpath as its install name so the host application will need to specify the framework location, usually by adding @loader_path/../Frameworks to the Runpath Search Paths in the Build Settings.