Refactored the shortcut dispatcher and bindings to user defaults.

This is a big change that was hard to split into smaller commits. There’s now
a new class to bind shortcuts to actions, a new class to bind user defaults’
keys to actions, and a new way to associate user defaults with the recorder
control (MASShortcutView). I have also updated the demo app to go with the
changes.

The new class to associate shortcuts with actions is called MASShortcutMonitor.
It wraps the Carbon hotkey magic and offers a simple interface to add a
shortcut along with a block that should be run when the shortcut is pressed.
It’s the lowest-level interface.

Since the usual requirement is to store the shortcuts into user defaults,
there’s also a higher-level interface offered by the MASShortcutBinder class.
That takes a defaults key and associates it with a block. When the shortcut
stored under the defaults key changes, the binder automatically switches to the
new shortcut. The class is a wrapper built atop of the previous one, the
MASShortcutMonitor – it simply adds, updates and removes shortcuts as the
user defaults change.

I have removed the special user defaults integration code from the recorder
control (MASShortcutView) and replaced it with a small Cocoa Bindings shim.
This means that in order to keep the recorder control in sync with the defaults
you just have to call the usual bind:toObject:withKeyPath:options: method,
like this:

[_shortcutView bind:MASShortcutBinding
    toObject:[NSUserDefaultsController sharedUserDefaultsController]
    withKeyPath[@"values.ExampleDefaultsKey"
    options:@{NSValueTransformerNameBindingOption:NSKeyedUnarchiveFromDataTransformerName}];

That’s more verbose than the previous solution, but it’s much cleaner and can
be swept under a convenience call if needed. I might also add a dictionaryValue
property later that would make it possible to bind the value to user defaults
directly, without a transformer, and would enable backward compatibility with
Shortcut Recorder.

1 files changed, 50 insertions, 0 deletions

diff --git a/Framework/MASShortcutView.m b/Framework/MASShortcutView.m
index 6f562a5..d03efbc 100644
--- a/Framework/MASShortcutView.m
+++ b/Framework/MASShortcutView.m
@@ -1,6 +1,8 @@
 #import "MASShortcutView.h"
 #import "MASShortcutValidator.h"
 
+NSString *const MASShortcutBinding = @"shortcutValue";
+
 #define HINT_BUTTON_WIDTH 23.0
 #define BUTTON_FONT_SIZE 11.0
 #define SEGMENT_CHROME_WIDTH 6.0
@@ -149,6 +151,7 @@
     _shortcutValue = shortcutValue;
     [self resetToolTips];
     [self setNeedsDisplay:YES];
+    [self propagateValue:shortcutValue forBinding:@"shortcutValue"];
 
     if (self.shortcutValueChange) {
         self.shortcutValueChange(self);
@@ -462,4 +465,51 @@ void *kUserDataHint = &kUserDataHint;
     }
 }
 
+#pragma mark Bindings
+
+// http://tomdalling.com/blog/cocoa/implementing-your-own-cocoa-bindings/
+-(void) propagateValue:(id)value forBinding:(NSString*)binding;
+{
+	NSParameterAssert(binding != nil);
+
+	//WARNING: bindingInfo contains NSNull, so it must be accounted for
+	NSDictionary* bindingInfo = [self infoForBinding:binding];
+	if(!bindingInfo)
+		return; //there is no binding
+
+	//apply the value transformer, if one has been set
+	NSDictionary* bindingOptions = [bindingInfo objectForKey:NSOptionsKey];
+	if(bindingOptions){
+		NSValueTransformer* transformer = [bindingOptions valueForKey:NSValueTransformerBindingOption];
+		if(!transformer || (id)transformer == [NSNull null]){
+			NSString* transformerName = [bindingOptions valueForKey:NSValueTransformerNameBindingOption];
+			if(transformerName && (id)transformerName != [NSNull null]){
+				transformer = [NSValueTransformer valueTransformerForName:transformerName];
+			}
+		}
+
+		if(transformer && (id)transformer != [NSNull null]){
+			if([[transformer class] allowsReverseTransformation]){
+				value = [transformer reverseTransformedValue:value];
+			} else {
+				NSLog(@"WARNING: binding \"%@\" has value transformer, but it doesn't allow reverse transformations in %s", binding, __PRETTY_FUNCTION__);
+			}
+		}
+	}
+
+	id boundObject = [bindingInfo objectForKey:NSObservedObjectKey];
+	if(!boundObject || boundObject == [NSNull null]){
+		NSLog(@"ERROR: NSObservedObjectKey was nil for binding \"%@\" in %s", binding, __PRETTY_FUNCTION__);
+		return;
+	}
+
+	NSString* boundKeyPath = [bindingInfo objectForKey:NSObservedKeyPathKey];
+	if(!boundKeyPath || (id)boundKeyPath == [NSNull null]){
+		NSLog(@"ERROR: NSObservedKeyPathKey was nil for binding \"%@\" in %s", binding, __PRETTY_FUNCTION__);
+		return;
+	}
+
+	[boundObject setValue:value forKeyPath:boundKeyPath];
+}
+
 @end