From 11c23308dd5368d5c819cfdbd06ab0c1cb81a41c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rene=CC=81=20Sprotte?= <rene.sprotte@provideal.net>
Date: Wed, 20 Jul 2011 10:30:39 +0200
Subject: [PATCH] Use drawRect instead of layoutSubviews to draw the cells.
 Fixes really sloppy performance and memory issues. Should all be good now.

---
 MMGridView/Classes/MMGridView.m     | 81 +++++++++++++----------------
 MMGridViewDemo/RootViewController.m | 20 +++++--
 2 files changed, 52 insertions(+), 49 deletions(-)

diff --git a/MMGridView/Classes/MMGridView.m b/MMGridView/Classes/MMGridView.m
index f0a2bcf..a209311 100644
--- a/MMGridView/Classes/MMGridView.m
+++ b/MMGridView/Classes/MMGridView.m
@@ -74,7 +74,33 @@ - (id)initWithCoder:(NSCoder *)aDecoder
 }
 
 
-- (void)layoutSubviews
+- (void)createSubviews
+{
+    cellMargin = 3;
+    numberOfRows = 3;
+    numberOfColumns = 2;
+    currentPageIndex = 0;
+    
+    self.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight; 
+    self.contentMode = UIViewContentModeRedraw;
+    self.backgroundColor = [UIColor clearColor];
+    
+    self.scrollView = [[[UIScrollView alloc] initWithFrame:self.bounds] autorelease];
+    self.scrollView.delegate = self;
+    self.scrollView.backgroundColor = [UIColor clearColor];
+    self.scrollView.autoresizingMask = UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleWidth;
+    self.scrollView.alwaysBounceHorizontal = NO;
+    self.scrollView.alwaysBounceVertical = NO;
+    self.scrollView.showsVerticalScrollIndicator = NO;
+    self.scrollView.showsHorizontalScrollIndicator = NO;
+    self.scrollView.pagingEnabled = YES;
+    [self addSubview:self.scrollView];
+    
+    [self reloadData];
+}
+
+
+- (void)drawRect:(CGRect)rect
 {
     if (self.dataSource && self.numberOfRows > 0 && self.numberOfColumns > 0) {
         NSInteger noOfCols = self.numberOfColumns;
@@ -95,50 +121,28 @@ - (void)layoutSubviews
         CGSize contentSize = CGSizeMake(self.numberOfPages * gridBounds.size.width, gridBounds.size.height);
         [self.scrollView setContentSize:contentSize];
         
+        for (UIView *v in self.scrollView.subviews) {
+            [v removeFromSuperview];
+        }
+
         for (NSInteger i = 0; i < [self.dataSource numberOfCellsInGridView:self]; i++) {
             MMGridViewCell *cell = [self.dataSource gridView:self cellAtIndex:i];
-
+         
             NSInteger page = (int)floor((float)i / (float)cellsPerPage);
             NSInteger row  = (int)floor((float)i / (float)noOfCols) - (page * noOfRows);
-            
+         
             CGPoint origin = CGPointMake((page * gridBounds.size.width) + ((i % noOfCols) * cellBounds.size.width), 
                                          (row * cellBounds.size.height));
-            
+         
             CGRect f = CGRectMake(origin.x, origin.y, cellBounds.size.width, cellBounds.size.height);
             cell.frame = CGRectInset(f, self.cellMargin, self.cellMargin);
-            
+         
             [self.scrollView addSubview:cell];
         }
     }
 }
 
 
-- (void)createSubviews
-{
-    cellMargin = 3;
-    numberOfRows = 3;
-    numberOfColumns = 2;
-    currentPageIndex = 0;
-    
-    self.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight; 
-    self.contentMode = UIViewContentModeRedraw;
-    self.backgroundColor = [UIColor clearColor];
-    
-    self.scrollView = [[[UIScrollView alloc] initWithFrame:self.bounds] autorelease];
-    self.scrollView.delegate = self;
-    self.scrollView.backgroundColor = [UIColor clearColor];
-    self.scrollView.autoresizingMask = UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleWidth;
-    self.scrollView.alwaysBounceHorizontal = NO;
-    self.scrollView.alwaysBounceVertical = NO;
-    self.scrollView.showsVerticalScrollIndicator = NO;
-    self.scrollView.showsHorizontalScrollIndicator = NO;
-    self.scrollView.pagingEnabled = YES;
-    [self addSubview:self.scrollView];
-    
-    [self reloadData];
-}
-
-
 - (void)setDataSource:(id<MMGridViewDataSource>)aDataSource
 {
     dataSource = aDataSource;
@@ -177,20 +181,7 @@ - (NSUInteger)numberOfPages
 
 - (void)reloadData
 {
-    for (UIView *v in self.scrollView.subviews) {
-        [v removeFromSuperview];
-    }
-    
-    if (self.dataSource && self.numberOfRows > 0 && self.numberOfColumns > 0) {       
-        for (NSInteger i = 0; i < [self.dataSource numberOfCellsInGridView:self]; i++) {
-            MMGridViewCell *cell = [self.dataSource gridView:self cellAtIndex:i];
-            [cell performSelector:@selector(setGridView:) withObject:self];
-            [cell performSelector:@selector(setIndex:) withObject:[NSNumber numberWithInt:i]];
-            [self.scrollView addSubview:cell];
-        }
-    }
-
-    [self setNeedsLayout];
+    [self setNeedsDisplay];
 }
 
 
diff --git a/MMGridViewDemo/RootViewController.m b/MMGridViewDemo/RootViewController.m
index 03e5b36..9364375 100644
--- a/MMGridViewDemo/RootViewController.m
+++ b/MMGridViewDemo/RootViewController.m
@@ -26,6 +26,7 @@
 
 @interface RootViewController()
 - (void)reload;
+- (void)setupPageControl;
 @end
 
 @implementation RootViewController
@@ -41,6 +42,7 @@ - (void)dealloc
     [super dealloc];
 }
 
+
 - (void)viewDidUnload {
     [gridView release];
     gridView = nil;
@@ -49,6 +51,7 @@ - (void)viewDidUnload {
     [super viewDidUnload];
 }
 
+
 - (void)viewDidLoad
 {
     // Give us a nice title
@@ -60,8 +63,12 @@ - (void)viewDidLoad
                                                                                   action:@selector(reload)];
     self.navigationItem.rightBarButtonItem = reloadButton;
     [reloadButton release];
+    
+    // setup the page control 
+    [self setupPageControl];
 }
 
+
 - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
 {
     // Return YES for supported orientations
@@ -76,13 +83,20 @@ - (void)reload
     [gridView reloadData];
 }
 
+
+- (void)setupPageControl
+{
+    pageControl.numberOfPages = gridView.numberOfPages;
+    pageControl.currentPage = gridView.currentPageIndex;
+}
+
 // ----------------------------------------------------------------------------------
 
 #pragma - MMGridViewDataSource
 
 - (NSInteger)numberOfCellsInGridView:(MMGridView *)gridView
 {
-    return 15;
+    return 42;
 }
 
 
@@ -90,7 +104,6 @@ - (MMGridViewCell *)gridView:(MMGridView *)gridView cellAtIndex:(NSUInteger)inde
 {
     MMGridViewDefaultCell *cell = [[[MMGridViewDefaultCell alloc] initWithFrame:CGRectNull] autorelease];
     cell.textLabel.text = [NSString stringWithFormat:@"Cell %d", index];
-    // cell.backgroundView.backgroundColor = [UIColor redColor];
     cell.backgroundView.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"cell-image.png"]];
     return cell;
 }
@@ -121,8 +134,7 @@ - (void)gridView:(MMGridView *)gridView didDoubleTapCell:(MMGridViewCell *)cell
 
 - (void)gridView:(MMGridView *)theGridView changedPageToIndex:(NSUInteger)index
 {
-    pageControl.numberOfPages = theGridView.numberOfPages;
-    pageControl.currentPage = index;
+    [self setupPageControl];
 }
 
 @end