Fixed exception when delegate doesn't add the barButtonItem to a suit…

…able bar, making the popover support now entirely optional (as it should be). Added the ability to put the Master _after_ the Detail instead of before it; works for both orientations, and includes an animated toggling action for convenience.

Classes/DetailViewController.h

@@ -14,6 +14,7 @@
 	IBOutlet UIBarButtonItem *toggleItem;
 	IBOutlet UIBarButtonItem *verticalItem;
 	IBOutlet UIBarButtonItem *dividerStyleItem;
+	IBOutlet UIBarButtonItem *masterBeforeDetailItem;
     UIPopoverController *popoverController;
     UIToolbar *toolbar;
 
@@ -28,5 +29,6 @@
 - (IBAction)toggleMasterView:(id)sender;
 - (IBAction)toggleVertical:(id)sender;
 - (IBAction)toggleDividerStyle:(id)sender;
+- (IBAction)toggleMasterBeforeDetail:(id)sender;
 
 @end

Classes/DetailViewController.m

@@ -52,6 +52,7 @@ - (void)configureView
 	toggleItem.title = ([splitController isShowingMaster]) ? @"Hide Master" : @"Show Master"; // "I... AM... THE MASTER!" Derek Jacobi. Gave me chills.
 	verticalItem.title = (splitController.vertical) ? @"Horizontal Split" : @"Vertical Split";
 	dividerStyleItem.title = (splitController.dividerStyle == MGSplitViewDividerStyleThin) ? @"Enable Dragging" : @"Disable Dragging";
+	masterBeforeDetailItem.title = (splitController.masterBeforeDetail) ? @"Detail First" : @"Master First";
 }
 
 
@@ -147,6 +148,13 @@ - (IBAction)toggleDividerStyle:(id)sender
 }
 
 
+- (IBAction)toggleMasterBeforeDetail:(id)sender
+{
+	[splitController toggleMasterBeforeDetail:sender];
+	[self configureView];
+}
+
+
 #pragma mark -
 #pragma mark Rotation support
 

Classes/MGSplitDividerView.m

@@ -187,6 +187,9 @@ - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
 		CGPoint lastPt = [touch previousLocationInView:self];
 		CGPoint pt = [touch locationInView:self];
 		float offset = (splitViewController.vertical) ? pt.x - lastPt.x : pt.y - lastPt.y;
+		if (!splitViewController.masterBeforeDetail) {
+			offset = -offset;
+		}
 		splitViewController.splitPosition = splitViewController.splitPosition + offset;
 	}
 }

Classes/MGSplitViewController.h

@@ -22,6 +22,7 @@ typedef enum _MGSplitViewDividerStyle {
 	float _splitWidth;
 	id _delegate;
 	BOOL _vertical;
+	BOOL _masterBeforeDetail;
 	NSMutableArray *_viewControllers;
 	UIBarButtonItem *_barButtonItem; // To be compliant with wacky UISplitViewController behaviour.
     UIPopoverController *_hiddenPopoverController; // Popover used to hold the master view if it's not always visible.
@@ -36,7 +37,8 @@ typedef enum _MGSplitViewDividerStyle {
 @property (nonatomic, assign) BOOL showsMasterInPortrait; // applies to both portrait orientations (default NO)
 @property (nonatomic, assign) BOOL showsMasterInLandscape; // applies to both landscape orientations (default YES)
 @property (nonatomic, assign, getter=isVertical) BOOL vertical; // if NO, split is horizontal, i.e. master above detail (default YES)
-@property (nonatomic, assign) float splitPosition; // starting position of split in pixels, relative to top or left (depending on .isVertical setting).
+@property (nonatomic, assign, getter=isMasterBeforeDetail) BOOL masterBeforeDetail; // if NO, master view is below/right of detail (default YES)
+@property (nonatomic, assign) float splitPosition; // starting position of split in pixels, relative to top/left (depending on .isVertical setting) if masterBeforeDetail is YES, else relative to bottom/right.
 @property (nonatomic, assign) float splitWidth; // width of split in pixels.
 @property (nonatomic, assign) BOOL allowsDraggingDivider; // whether to let the user drag the divider to alter the split position (default NO).
 
@@ -50,13 +52,23 @@ typedef enum _MGSplitViewDividerStyle {
 
 // Actions
 - (IBAction)toggleSplitOrientation:(id)sender; // toggles split axis between vertical (left/right; default) and horizontal (top/bottom).
+- (IBAction)toggleMasterBeforeDetail:(id)sender; // toggles position of master view relative to detail view.
 - (IBAction)toggleMasterView:(id)sender; // toggles display of the master view in the current orientation.
 - (IBAction)showMasterPopover:(id)sender; // shows the master view in a popover spawned from the provided barButtonItem, if it's currently hidden.
 - (void)notePopoverDismissed; // should rarely be needed, because you should not change the popover's delegate. If you must, then call this when it's dismissed.
 
 // Conveniences for you, because I care.
 - (BOOL)isShowingMaster;
 - (void)setSplitPosition:(float)posn animated:(BOOL)animate; // Allows for animation of splitPosition changes. The property's regular setter is not animated.
+/* Note:	splitPosition is the width (in a left/right split, or height in a top/bottom split) of the master view.
+			It is relative to the appropriate side of the splitView, which can be any of the four sides depending on the values in isMasterBeforeDetail and isVertical:
+				isVertical = YES, isMasterBeforeDetail = YES: splitPosition is relative to the LEFT edge. (Default)
+				isVertical = YES, isMasterBeforeDetail = NO: splitPosition is relative to the RIGHT edge.
+ 				isVertical = NO, isMasterBeforeDetail = YES: splitPosition is relative to the TOP edge.
+ 				isVertical = NO, isMasterBeforeDetail = NO: splitPosition is relative to the BOTTOM edge.
+
+			This implementation was chosen so you don't need to recalculate equivalent splitPositions if the user toggles masterBeforeDetail themselves.
+ */
 - (void)setDividerStyle:(MGSplitViewDividerStyle)newStyle animated:(BOOL)animate; // Allows for animation of dividerStyle changes. The property's regular setter is not animated.
 - (NSArray *)cornerViews;
 /*

Classes/MGSplitViewController.m

@@ -21,6 +21,7 @@
 #define MG_MIN_VIEW_WIDTH				200.0	// minimum width a view is allowed to become as a result of changing the splitPosition.
 
 #define MG_ANIMATION_CHANGE_SPLIT_ORIENTATION	@"ChangeSplitOrientation"	// Animation ID for internal use.
+#define MG_ANIMATION_CHANGE_SUBVIEWS_ORDER		@"ChangeSubviewsOrder"	// Animation ID for internal use.
 
 
 @interface MGSplitViewController (MGPrivateMethods)
@@ -127,6 +128,7 @@ - (void)setup
 	_showsMasterInLandscape = YES;
 	_reconfigurePopup = NO;
 	_vertical = YES;
+	_masterBeforeDetail = YES;
 	_splitPosition = MG_DEFAULT_SPLIT_POSITION;
 	CGRect divRect = self.view.bounds;
 	if ([self isVertical]) {
@@ -268,45 +270,72 @@ - (void)layoutSubviewsForInterfaceOrientation:(UIInterfaceOrientation)theOrienta
 	UIViewController *controller;
 	UIView *theView;
 	BOOL shouldShowMaster = [self shouldShowMasterForInterfaceOrientation:theOrientation];
+	BOOL masterFirst = [self isMasterBeforeDetail];
 	if ([self isVertical]) {
-		// Master on left, detail on right.
-		if (!shouldShowMaster) {
-			// Move off-screen.
-			newFrame.origin.x -= (_splitPosition + _splitWidth);
+		// Master on left, detail on right (or vice versa).
+		CGRect masterRect, dividerRect, detailRect;
+		if (masterFirst) {
+			if (!shouldShowMaster) {
+				// Move off-screen.
+				newFrame.origin.x -= (_splitPosition + _splitWidth);
+			}
+
+			newFrame.size.width = _splitPosition;
+			masterRect = newFrame;
+
+			newFrame.origin.x += newFrame.size.width;
+			newFrame.size.width = _splitWidth;
+			dividerRect = newFrame;
+
+			newFrame.origin.x += newFrame.size.width;
+			newFrame.size.width = width - newFrame.origin.x;
+			detailRect = newFrame;
+
+		} else {
+			if (!shouldShowMaster) {
+				// Move off-screen.
+				newFrame.size.width += (_splitPosition + _splitWidth);
+			}
+
+			newFrame.size.width -= (_splitPosition + _splitWidth);
+			detailRect = newFrame;
+
+			newFrame.origin.x += newFrame.size.width;
+			newFrame.size.width = _splitWidth;
+			dividerRect = newFrame;
+
+			newFrame.origin.x += newFrame.size.width;
+			newFrame.size.width = _splitPosition;
+			masterRect = newFrame;
 		}
 
 		// Position master.
 		controller = self.masterViewController;
 		if (controller && [controller isKindOfClass:[UIViewController class]])  {
 			theView = controller.view;
 			if (theView) {
-				newFrame.size.width = _splitPosition;
-				theView.frame = newFrame;
+				theView.frame = masterRect;
 				if (!theView.superview) {
-					[self.masterViewController viewWillAppear:NO];
+					[controller viewWillAppear:NO];
 					[self.view addSubview:theView];
-					[self.masterViewController viewDidAppear:NO];
+					[controller viewDidAppear:NO];
 				}
-				newFrame.origin.x += newFrame.size.width;
 			}
 		}
 
 		// Position divider.
 		theView = _dividerView;
-		newFrame.size.width = _splitWidth;
-		theView.frame = newFrame;
+		theView.frame = dividerRect;
 		if (!theView.superview) {
 			[self.view addSubview:theView];
 		}
-		newFrame.origin.x += newFrame.size.width;
 
 		// Position detail.
 		controller = self.detailViewController;
 		if (controller && [controller isKindOfClass:[UIViewController class]])  {
 			theView = controller.view;
 			if (theView) {
-				newFrame.size.width = width - newFrame.origin.x;
-				theView.frame = newFrame;
+				theView.frame = detailRect;
 				if (!theView.superview) {
 					[self.view insertSubview:theView aboveSubview:self.masterViewController.view];
 				} else {
@@ -316,44 +345,70 @@ - (void)layoutSubviewsForInterfaceOrientation:(UIInterfaceOrientation)theOrienta
 		}
 
 	} else {
-		// Master above, detail below.
-		if (![self shouldShowMasterForInterfaceOrientation:theOrientation]) {
-			// Move off-screen.
-			newFrame.origin.y -= (_splitPosition + _splitWidth);
+		// Master above, detail below (or vice versa).
+		CGRect masterRect, dividerRect, detailRect;
+		if (masterFirst) {
+			if (!shouldShowMaster) {
+				// Move off-screen.
+				newFrame.origin.y -= (_splitPosition + _splitWidth);
+			}
+
+			newFrame.size.height = _splitPosition;
+			masterRect = newFrame;
+
+			newFrame.origin.y += newFrame.size.height;
+			newFrame.size.height = _splitWidth;
+			dividerRect = newFrame;
+
+			newFrame.origin.y += newFrame.size.height;
+			newFrame.size.height = height - newFrame.origin.y;
+			detailRect = newFrame;
+
+		} else {
+			if (!shouldShowMaster) {
+				// Move off-screen.
+				newFrame.size.height += (_splitPosition + _splitWidth);
+			}
+
+			newFrame.size.height -= (_splitPosition + _splitWidth);
+			detailRect = newFrame;
+
+			newFrame.origin.y += newFrame.size.height;
+			newFrame.size.height = _splitWidth;
+			dividerRect = newFrame;
+
+			newFrame.origin.y += newFrame.size.height;
+			newFrame.size.height = _splitPosition;
+			masterRect = newFrame;
 		}
 
 		// Position master.
 		controller = self.masterViewController;
 		if (controller && [controller isKindOfClass:[UIViewController class]])  {
 			theView = controller.view;
 			if (theView) {
-				newFrame.size.height = _splitPosition;
-				theView.frame = newFrame;
+				theView.frame = masterRect;
 				if (!theView.superview) {
-					[self.masterViewController viewWillAppear:NO];
+					[controller viewWillAppear:NO];
 					[self.view addSubview:theView];
-					[self.masterViewController viewDidAppear:NO];
+					[controller viewDidAppear:NO];
 				}
-				newFrame.origin.y += newFrame.size.height;
 			}
 		}
 
 		// Position divider.
 		theView = _dividerView;
-		newFrame.size.height = _splitWidth;
-		theView.frame = newFrame;
+		theView.frame = dividerRect;
 		if (!theView.superview) {
 			[self.view addSubview:theView];
 		}
-		newFrame.origin.y += newFrame.size.height;
 
 		// Position detail.
 		controller = self.detailViewController;
 		if (controller && [controller isKindOfClass:[UIViewController class]])  {
 			theView = controller.view;
 			if (theView) {
-				newFrame.size.height = height - newFrame.origin.y;
-				theView.frame = newFrame;
+				theView.frame = detailRect;
 				if (!theView.superview) {
 					[self.view insertSubview:theView aboveSubview:self.masterViewController.view];
 				} else {
@@ -397,14 +452,14 @@ - (void)layoutSubviewsForInterfaceOrientation:(UIInterfaceOrientation)theOrienta
 	if (_vertical) { // left/right split
 		cornersWidth = (radius * 2.0) + _splitWidth;
 		cornersHeight = radius;
-		x = ((shouldShowMaster) ? _splitPosition : (0 - _splitWidth)) - radius;
+		x = ((shouldShowMaster) ? ((masterFirst) ? _splitPosition : width - (_splitPosition + _splitWidth)) : (0 - _splitWidth)) - radius;
 		y = 0;
 		leadingRect = CGRectMake(x, y, cornersWidth, cornersHeight); // top corners
 		trailingRect = CGRectMake(x, (height - cornersHeight), cornersWidth, cornersHeight); // bottom corners
 
 	} else { // top/bottom split
 		x = 0;
-		y = ((shouldShowMaster) ? _splitPosition : (0 - _splitWidth)) - radius;
+		y = ((shouldShowMaster) ? ((masterFirst) ? _splitPosition : height - (_splitPosition + _splitWidth)) : (0 - _splitWidth)) - radius;
 		cornersWidth = radius;
 		cornersHeight = (radius * 2.0) + _splitWidth;
 		leadingRect = CGRectMake(x, y, cornersWidth, cornersHeight); // left corners
@@ -521,7 +576,7 @@ - (void)reconfigureForMasterInPopover:(BOOL)inPopover
 
 	} else if (!inPopover && _hiddenPopoverController && _barButtonItem) {
 		// I know this looks strange, but it fixes a bizarre issue with UIPopoverController leaving masterViewController's views in disarray.
-		[_hiddenPopoverController presentPopoverFromBarButtonItem:_barButtonItem permittedArrowDirections:UIPopoverArrowDirectionAny animated:NO];
+		[_hiddenPopoverController presentPopoverFromRect:CGRectZero inView:self.view permittedArrowDirections:UIPopoverArrowDirectionAny animated:NO];
 
 		// Remove master from popover and destroy popover, if it exists.
 		[_hiddenPopoverController dismissPopoverAnimated:NO];
@@ -566,7 +621,9 @@ - (void)notePopoverDismissed
 
 - (void)animationDidStop:(NSString *)animationID finished:(NSNumber *)finished context:(void *)context
 {
-	if ([animationID isEqualToString:MG_ANIMATION_CHANGE_SPLIT_ORIENTATION] && _cornerViews) {
+	if (([animationID isEqualToString:MG_ANIMATION_CHANGE_SPLIT_ORIENTATION] || 
+		 [animationID isEqualToString:MG_ANIMATION_CHANGE_SUBVIEWS_ORDER])
+		&& _cornerViews) {
 		for (UIView *corner in _cornerViews) {
 			corner.hidden = NO;
 		}
@@ -600,6 +657,27 @@ - (IBAction)toggleSplitOrientation:(id)sender
 }
 
 
+- (IBAction)toggleMasterBeforeDetail:(id)sender
+{
+	BOOL showingMaster = [self isShowingMaster];
+	if (showingMaster) {
+		if (_cornerViews) {
+			for (UIView *corner in _cornerViews) {
+				corner.hidden = YES;
+			}
+			_dividerView.hidden = YES;
+		}
+		[UIView beginAnimations:MG_ANIMATION_CHANGE_SUBVIEWS_ORDER context:nil];
+		[UIView setAnimationDelegate:self];
+		[UIView setAnimationDidStopSelector:@selector(animationDidStop:finished:context:)];
+	}
+	self.masterBeforeDetail = (!self.masterBeforeDetail);
+	if (showingMaster) {
+		[UIView commitAnimations];
+	}
+}
+
+
 - (IBAction)toggleMasterView:(id)sender
 {
 	if (_hiddenPopoverController && _hiddenPopoverController.popoverVisible) {
@@ -732,6 +810,28 @@ - (void)setVertical:(BOOL)flag
 }
 
 
+- (BOOL)isMasterBeforeDetail
+{
+	return _masterBeforeDetail;
+}
+
+
+- (void)setMasterBeforeDetail:(BOOL)flag
+{
+	if (flag != _masterBeforeDetail) {
+		if (_hiddenPopoverController && _hiddenPopoverController.popoverVisible) {
+			[_hiddenPopoverController dismissPopoverAnimated:NO];
+		}
+
+		_masterBeforeDetail = flag;
+
+		if ([self isShowingMaster]) {
+			[self layoutSubviews];
+		}
+	}
+}
+
+
 - (float)splitPosition
 {
 	return _splitPosition;