Revert "Refactor KVO"

This reverts commit 5647777.

DAKeyboardControl/DAKeyboardControl.m

@@ -133,11 +133,6 @@ - (void)addKeyboardControl:(BOOL)panning actionHandler:(DAKeyboardDidMoveBlock)a
         [self.keyboardPanRecognizer setDelegate:self];
         [self addGestureRecognizer:self.keyboardPanRecognizer];
     }
-
-    [self addObserver:self
-           forKeyPath:@"keyboardActiveView.frame"
-              options:0
-              context:NULL];
 }
 
 - (CGRect)keyboardFrameInView
@@ -193,7 +188,6 @@ - (void)removeKeyboardControl
 
     // Unregister any gesture recognizer
     [self removeGestureRecognizer:self.keyboardPanRecognizer];
-    [self removeObserver:self forKeyPath:@"keyboardActiveView.frame"];
 
     // Release a few properties
     self.keyboardDidMoveBlock = nil;
@@ -337,9 +331,9 @@ - (void)observeValueForKeyPath:(NSString *)keyPath
                         change:(NSDictionary *)change
                        context:(void *)context
 {
-    if([keyPath isEqualToString:@"keyboardActiveView.frame"] && self.keyboardActiveView)
+    if([keyPath isEqualToString:@"frame"] && object == self.keyboardActiveView)
     {
-        CGRect keyboardEndFrameWindow = self.keyboardActiveView.frame;
+        CGRect keyboardEndFrameWindow = [[object valueForKeyPath:keyPath] CGRectValue];
         CGRect keyboardEndFrameView = [self convertRect:keyboardEndFrameWindow fromView:self.keyboardActiveView.window];
         if (self.keyboardDidMoveBlock && !self.keyboardActiveView.hidden)
         {
@@ -589,6 +583,15 @@ - (UIView *)keyboardActiveView
 - (void)setKeyboardActiveView:(UIView *)keyboardActiveView
 {
     [self willChangeValueForKey:@"keyboardActiveView"];
+    [self.keyboardActiveView removeObserver:self
+                                 forKeyPath:@"frame"];
+    if (keyboardActiveView)
+    {
+        [keyboardActiveView addObserver:self
+                             forKeyPath:@"frame"
+                                options:0
+                                context:NULL];
+    }
     objc_setAssociatedObject(self,
                              &UIViewKeyboardActiveView,
                              keyboardActiveView,