CollectionView supports grouping

BCCollectionView.h

@@ -46,6 +46,7 @@
 @property (nonatomic, copy) NSString *zoomValueObserverKey, *accumulatedKeyStrokes;
 
 @property (readonly) NSArray *visibleViewControllerArray;
+@property (readonly) BCCollectionViewLayoutManager *layoutManager;
 
 //designated way to load BCCollectionView
 - (void)reloadDataWithItems:(NSArray *)newContent emptyCaches:(BOOL)shouldEmptyCaches;

BCCollectionView.m

@@ -4,9 +4,10 @@
 #import "BCCollectionView.h"
 #import "BCGeometryExtensions.h"
 #import "BCCollectionViewLayoutManager.h"
+#import "BCCollectionViewGroup.h"
 
 @implementation BCCollectionView
-@synthesize delegate, contentArray, backgroundColor, originalSelectionIndexes, zoomValueObserverKey, accumulatedKeyStrokes, numberOfPreRenderedRows;
+@synthesize delegate, contentArray, backgroundColor, originalSelectionIndexes, zoomValueObserverKey, accumulatedKeyStrokes, numberOfPreRenderedRows, layoutManager;
 @dynamic visibleViewControllerArray;
 
 - (id)initWithCoder:(NSCoder *)aDecoder
@@ -112,6 +113,14 @@ - (void)drawRect:(NSRect)dirtyRect
 
   if (dragHoverIndex != NSNotFound && [self shoulDrawHover])
     [self drawItemSelectionForInRect:[[[visibleViewControllers objectForKey:[NSNumber numberWithInteger:dragHoverIndex]] view] frame]];
+
+  if ([delegate respondsToSelector:@selector(collectionView:drawGroupSeparator:inRect:)]) {
+    NSRect groupRect = NSMakeRect(0, 0, NSWidth([self visibleRect]), BCCollectionViewGroupHeight);
+    for (BCCollectionViewGroup *group in [layoutManager groups]) {
+      groupRect.origin.y = [layoutManager rectOfItemAtIndex:[group itemRange].location].origin.y-BCCollectionViewGroupHeight;
+      [delegate collectionView:self drawGroupSeparator:group inRect:groupRect];
+    }
+  }
 }
 
 #pragma mark Delegate Call Wrappers
@@ -208,10 +217,25 @@ - (NSIndexSet *)indexesOfItemContentRectsInRect:(NSRect)aRect
 - (NSRange)rangeOfVisibleItems
 {
   NSRect visibleRect = [self visibleRect];
-  NSUInteger firstIndex = [layoutManager indexOfItemAtPointOrClosestGuess:NSMakePoint(NSMinX(visibleRect), NSMinY(visibleRect))];
-  NSUInteger lastIndex  = [layoutManager indexOfItemAtPointOrClosestGuess:NSMakePoint(NSMaxX(visibleRect), NSMaxY(visibleRect))];
-  return NSIntersectionRange(NSMakeRange(firstIndex, lastIndex-firstIndex),
-                             NSMakeRange(0, [contentArray count]));
+  NSInteger numberOfRows = [layoutManager numberOfRows];
+  NSInteger indexOfFirstItemAtRow = 0;
+  NSInteger firstIndex = NSNotFound;
+  NSInteger lastIndex  = NSNotFound;
+
+  for (NSInteger i=0; i<numberOfRows; i++) {
+    NSRect r = [layoutManager rectOfItemAtIndex:indexOfFirstItemAtRow];
+    BOOL rowIsVisible = NSIntersectionRange(NSMakeRange(r.origin.y, r.size.height), NSMakeRange(visibleRect.origin.y, visibleRect.size.height)).length != 0;
+
+    if (firstIndex == NSNotFound && rowIsVisible)
+      firstIndex = indexOfFirstItemAtRow;
+    if (firstIndex != NSNotFound && !rowIsVisible)
+      lastIndex = indexOfFirstItemAtRow-1;
+    if (firstIndex != NSNotFound && lastIndex != NSNotFound)
+      return NSMakeRange(firstIndex, lastIndex-firstIndex);
+
+    indexOfFirstItemAtRow += [layoutManager numberOfItemsAtRow:i];
+  }
+  return NSMakeRange(firstIndex, lastIndex-firstIndex);
 }
 
 - (NSRange)rangeOfVisibleItemsWithOverflow
@@ -428,7 +452,7 @@ - (void)softReloadVisibleViewControllers
 - (void)resizeFrameToFitContents
 {
   NSRect frame = [self frame];
-  frame.size.height = MAX([self visibleRect].size.height, [layoutManager numberOfRows] * [self cellSize].height);
+  frame.size.height = MAX([self visibleRect].size.height, NSMaxY([layoutManager rectOfItemAtIndex:[contentArray count]-1]));
   [self setFrame:frame];
 }
 
@@ -440,26 +464,27 @@ - (void)reloadDataWithItems:(NSArray *)newContent emptyCaches:(BOOL)shouldEmptyC
     return;
 
   self.contentArray = newContent;
-  [layoutManager willReload];
-  [self resizeFrameToFitContents];
-
-  if (shouldEmptyCaches) {
-    for (NSViewController *viewController in [visibleViewControllers allValues]) {
-      [[viewController view] removeFromSuperview];
-      if ([delegate respondsToSelector:@selector(collectionView:viewControllerBecameInvisible:)])
-        [delegate collectionView:self viewControllerBecameInvisible:viewController];
-    }
+  [layoutManager reloadWithCompletionBlock:^{
+    [self resizeFrameToFitContents];
 
-    [reusableViewControllers removeAllObjects];
-    [visibleViewControllers removeAllObjects];
-  } else
-    [self softReloadVisibleViewControllers];
-
-  [selectionIndexes removeAllIndexes];
-
-  dispatch_async(dispatch_get_main_queue(), ^{
-    [self addMissingViewControllersToView];
-  });
+    if (shouldEmptyCaches) {
+      for (NSViewController *viewController in [visibleViewControllers allValues]) {
+        [[viewController view] removeFromSuperview];
+        if ([delegate respondsToSelector:@selector(collectionView:viewControllerBecameInvisible:)])
+          [delegate collectionView:self viewControllerBecameInvisible:viewController];
+      }
+
+      [reusableViewControllers removeAllObjects];
+      [visibleViewControllers removeAllObjects];
+    } else
+      [self softReloadVisibleViewControllers];
+
+    [selectionIndexes removeAllIndexes];
+
+    dispatch_async(dispatch_get_main_queue(), ^{
+      [self addMissingViewControllersToView];
+    });
+  }];
 }
 
 - (void)scrollViewDidScroll:(NSNotification *)note
@@ -480,13 +505,13 @@ - (void)scrollViewDidScroll:(NSNotification *)note
 
 - (void)viewDidResize
 {
-  [layoutManager willReload];
-  [self resizeFrameToFitContents];
-  dispatch_async(dispatch_get_main_queue(), ^{
-    [layoutManager willReload];
-    [self moveViewControllersToProperPosition];
-    [self addMissingViewControllersToView];
-  });
+  [layoutManager reloadWithCompletionBlock:^{
+    [self resizeFrameToFitContents];
+    dispatch_async(dispatch_get_main_queue(), ^{
+      [self moveViewControllersToProperPosition];
+      [self addMissingViewControllersToView];
+    });
+  }];
 }
 
 - (NSMenu *)menuForEvent:(NSEvent *)anEvent

BCCollectionViewDelegate.h

@@ -3,7 +3,7 @@
 
 #import <Cocoa/Cocoa.h>
 
-@class BCCollectionView;
+@class BCCollectionView, BCCollectionViewGroup;
 
 enum {
   BCCollectionViewScrollDirectionUp   = 0,
@@ -44,6 +44,8 @@ enum {
 - (BOOL)collectionViewShouldDrawSelections:(BCCollectionView *)collectionView;
 - (BOOL)collectionViewShouldDrawHover:(BCCollectionView *)collectionView;
 
+- (void)collectionView:(BCCollectionView *)collectionView drawGroupSeparator:(BCCollectionViewGroup *)group inRect:(NSRect)rect;
+
 //managing Drag & Drop (in order of occurence)
 - (BOOL)collectionView:(BCCollectionView *)collectionView canDragItemsAtIndexes:(NSIndexSet *)indexSet;
 - (void)collectionView:(BCCollectionView *)collectionView writeItemsAtIndexes:(NSIndexSet *)indexSet toPasteboard:(NSPasteboard *)pboard;

BCCollectionViewGroup.h

@@ -0,0 +1,19 @@
+//  Created by Pieter Omvlee on 01/03/2011.
+//  Copyright 2011 Bohemian Coding. All rights reserved.
+
+#import <Foundation/Foundation.h>
+
+#define BCCollectionViewGroupHeight 30
+
+@interface BCCollectionViewGroup : NSObject
+{
+  NSString *title;
+  NSRange itemRange;
+  BOOL isCollapsed;
+}
++ (id)groupWithTitle:(NSString *)title range:(NSRange)range;
+@property (copy) NSString *title;
+@property NSRange itemRange;
+@property (setter=setCollapsed:) BOOL isCollapsed;
+
+@end

BCCollectionViewGroup.m

@@ -0,0 +1,23 @@
+//  Created by Pieter Omvlee on 01/03/2011.
+//  Copyright 2011 Bohemian Coding. All rights reserved.
+
+#import "BCCollectionViewGroup.h"
+
+@implementation BCCollectionViewGroup
+@synthesize title, itemRange, isCollapsed;
+
++ (id)groupWithTitle:(NSString *)title range:(NSRange)range
+{
+  BCCollectionViewGroup *group = [[BCCollectionViewGroup alloc] init];
+  [group setTitle:title];
+  [group setItemRange:range];
+  return [group autorelease];
+}
+
+- (void)dealloc
+{
+  [title release];
+  [super dealloc];
+}
+
+@end

BCCollectionViewItemLayout.h

@@ -0,0 +1,14 @@
+//  Created by Pieter Omvlee on 01/03/2011.
+//  Copyright 2011 Bohemian Coding. All rights reserved.
+
+#import <Foundation/Foundation.h>
+
+@interface BCCollectionViewItemLayout : NSObject
+{
+  NSInteger rowIndex, columnIndex, itemIndex;
+  NSRect itemRect;
+}
+@property NSInteger rowIndex, columnIndex, itemIndex;
+@property NSRect itemRect;
++ (id)layoutItem;
+@end

BCCollectionViewItemLayout.m

@@ -0,0 +1,14 @@
+//  Created by Pieter Omvlee on 01/03/2011.
+//  Copyright 2011 Bohemian Coding. All rights reserved.
+
+#import "BCCollectionViewItemLayout.h"
+
+@implementation BCCollectionViewItemLayout
+@synthesize rowIndex, columnIndex, itemRect, itemIndex;
+
++ (id)layoutItem
+{
+  return [[[self alloc] init] autorelease];
+}
+
+@end

BCCollectionViewLayoutManager.h

@@ -8,19 +8,25 @@
 {
   BCCollectionView *collectionView;
   NSInteger numberOfRows;
+  NSArray *groups;
+  NSMutableArray *itemLayouts;
+
+  NSOperationQueue *queue;
 }
+@property (copy) NSArray *groups;
 - (id)initWithCollectionView:(BCCollectionView *)collectionView; //assigned
+- (void)reloadWithCompletionBlock:(dispatch_block_t)completionBlock;
 
-- (void)willReload;
+#pragma mark Primitives
 - (NSUInteger)numberOfRows;
 - (NSUInteger)numberOfItemsAtRow:(NSInteger)rowIndex;
-- (NSUInteger)rowOfItemAtIndex:(NSInteger)anIndex;
 - (NSSize)cellSize;
-- (NSUInteger)indexOfItemAtPointOrClosestGuess:(NSPoint)p;
-
-- (NSRect)rectOfItemAtIndex:(NSUInteger)anIndex;
-- (NSRect)contentRectOfItemAtIndex:(NSUInteger)anIndex;
 
+#pragma mark From Point to Index
 - (NSUInteger)indexOfItemAtPoint:(NSPoint)p;
 - (NSUInteger)indexOfItemContentRectAtPoint:(NSPoint)p;
+
+#pragma mark From Index to Rect
+- (NSRect)rectOfItemAtIndex:(NSUInteger)anIndex;
+- (NSRect)contentRectOfItemAtIndex:(NSUInteger)anIndex;
 @end