Added properties to see the numberOfPages and the currentPageIndex. A…

…dded delegate method to know if the current page has changed.
siuying · Apr 10, 2011 · c5d2c81 · c5d2c81
1 parent 60d7cff
commit c5d2c81
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Showing 3 changed files with 56 additions and 13 deletions.
diff --git a/MMGridView/Classes/MMGridView.h b/MMGridView/Classes/MMGridView.h
@@ -31,7 +31,7 @@
 
 @protocol MMGridViewDataSource<NSObject>
 - (NSInteger)numberOfCellsInGridView:(MMGridView *)gridView;
-- (MMGridViewCell *)gridView:(MMGridView *)gridView cellAtIndex:(NSInteger)index;
+- (MMGridViewCell *)gridView:(MMGridView *)gridView cellAtIndex:(NSUInteger)index;
 @end
 
 // ----------------------------------------------------------------------------------
@@ -40,15 +40,16 @@
 
 @protocol MMGridViewDelegate<NSObject>
 @optional
-- (void)gridView:(MMGridView *)gridView didSelectCell:(MMGridViewCell *)cell atIndex:(NSInteger)index;
-- (void)gridView:(MMGridView *)gridView didDoubleTappedCell:(MMGridViewCell *)cell atIndex:(NSInteger)index;
+- (void)gridView:(MMGridView *)gridView didSelectCell:(MMGridViewCell *)cell atIndex:(NSUInteger)index;
+- (void)gridView:(MMGridView *)gridView didDoubleTappedCell:(MMGridViewCell *)cell atIndex:(NSUInteger)index;
+- (void)gridView:(MMGridView *)gridView changedPageToIndex:(NSUInteger)index;
 @end
 
 // ----------------------------------------------------------------------------------
 
 #pragma - MMGridView
 
-@interface MMGridView : UIView 
+@interface MMGridView : UIView<UIScrollViewDelegate> 
 {
     @private
     UIScrollView *scrollView;
@@ -65,6 +66,8 @@
 @property (nonatomic) NSUInteger numberOfRows;
 @property (nonatomic) NSUInteger numberOfColumns;
 @property (nonatomic) NSUInteger cellMargin;
+@property (nonatomic, readonly) NSUInteger currentPageIndex;
+@property (nonatomic, readonly) NSUInteger numberOfPages;
 
 - (void)reloadData;
 

diff --git a/MMGridView/Classes/MMGridView.m b/MMGridView/Classes/MMGridView.m
@@ -25,10 +25,13 @@
 @interface MMGridView()
 
 @property (nonatomic, retain) UIScrollView *scrollView;
+@property (nonatomic) NSUInteger currentPageIndex;
+@property (nonatomic) NSUInteger numberOfPages;
 
 - (void)createSubviews;
 - (void)cellWasSelected:(MMGridViewCell *)cell;
 - (void)cellWasDoubleTapped:(MMGridViewCell *)cell;
+- (void)updateCurrentPageIndex;
 @end
 
 
@@ -40,6 +43,8 @@ @implementation MMGridView
 @synthesize numberOfRows;
 @synthesize numberOfColumns;
 @synthesize cellMargin;
+@synthesize currentPageIndex;
+@synthesize numberOfPages;
 
 
 - (void)dealloc
@@ -77,10 +82,12 @@ - (void)createSubviews
     self.cellMargin = 3;
     self.numberOfRows = 3;
     self.numberOfColumns = 2;
+    self.currentPageIndex = 0;
 
     self.backgroundColor = [UIColor clearColor];
 
     self.scrollView = [[UIScrollView alloc] initWithFrame:CGRectNull];
+    self.scrollView.delegate = self;
     self.scrollView.backgroundColor = [UIColor clearColor];
     self.scrollView.autoresizingMask = UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleWidth;
     self.scrollView.alwaysBounceHorizontal = NO;
@@ -123,6 +130,14 @@ - (void)setCellMargin:(NSUInteger)value
 }
 
 
+- (NSUInteger)numberOfPages
+{
+    NSUInteger numberOfCells = [self.dataSource numberOfCellsInGridView:self];
+    NSUInteger cellsPerPage = self.numberOfColumns * self.numberOfRows;
+    return (uint)(ceil((float)numberOfCells / (float)cellsPerPage));
+}
+
+
 - (void)layoutSubviews
 {
     self.scrollView.frame = CGRectMake(0, 0, self.bounds.size.width, self.bounds.size.height);
@@ -139,7 +154,7 @@ - (void)reloadData
     if (self.dataSource) {
         NSInteger noOfCols = self.numberOfColumns;
         NSInteger noOfRows = self.numberOfRows;
-        NSInteger cellsPerPage = noOfCols * noOfRows;
+        NSUInteger cellsPerPage = self.numberOfColumns * self.numberOfRows;
 
         BOOL isLandscape = UIInterfaceOrientationIsLandscape([[UIDevice currentDevice] orientation]);
         if (isLandscape) {
@@ -148,17 +163,14 @@ - (void)reloadData
             noOfRows = self.numberOfColumns;
         }
 
-        NSInteger numberOfCells = [self.dataSource numberOfCellsInGridView:self];
-        NSInteger numberOfPages = (int)(ceil((float)numberOfCells / (float)cellsPerPage));
-
         CGRect gridBounds = self.scrollView.bounds;
         CGRect cellBounds = CGRectMake(0, 0, gridBounds.size.width / (float)noOfCols, 
                                        gridBounds.size.height / (float)noOfRows);
 
-        CGSize contentSize = CGSizeMake(numberOfPages * gridBounds.size.width, gridBounds.size.height);
+        CGSize contentSize = CGSizeMake(self.numberOfPages * gridBounds.size.width, gridBounds.size.height);
         [self.scrollView setContentSize:contentSize];
 
-        for (NSInteger i = 0; i < numberOfCells; i++) {
+        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]];
@@ -194,4 +206,25 @@ - (void)cellWasDoubleTapped:(MMGridViewCell *)cell
     }
 }
 
+
+- (void)updateCurrentPageIndex
+{
+    CGFloat pageWidth = scrollView.frame.size.width;
+    NSUInteger cpi = floor((scrollView.contentOffset.x - pageWidth / 2) / pageWidth) + 1;
+    self.currentPageIndex = cpi;
+
+    if (delegate) {
+        [self.delegate gridView:self changedPageToIndex:self.currentPageIndex];
+    }
+}
+
+// ----------------------------------------------------------------------------------
+
+#pragma - UIScrollViewDelegate
+
+- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
+{
+    [self updateCurrentPageIndex];
+}
+
 @end
diff --git a/MMGridViewDemo/RootViewController.m b/MMGridViewDemo/RootViewController.m
@@ -70,7 +70,7 @@ - (NSInteger)numberOfCellsInGridView:(MMGridView *)gridView
 }
 
 
-- (MMGridViewCell *)gridView:(MMGridView *)gridView cellAtIndex:(NSInteger)index
+- (MMGridViewCell *)gridView:(MMGridView *)gridView cellAtIndex:(NSUInteger)index
 {
     MMGridViewCell *cell = [[[MMGridViewCell alloc] initWithFrame:CGRectNull] autorelease];
     cell.textLabel.text = [NSString stringWithFormat:@"Cell %d", index];
@@ -81,15 +81,15 @@ - (MMGridViewCell *)gridView:(MMGridView *)gridView cellAtIndex:(NSInteger)index
 
 #pragma - MMGridViewDelegate
 
-- (void)gridView:(MMGridView *)gridView didSelectCell:(MMGridViewCell *)cell atIndex:(NSInteger)index
+- (void)gridView:(MMGridView *)gridView didSelectCell:(MMGridViewCell *)cell atIndex:(NSUInteger)index
 {
     AnyViewController *c = [[AnyViewController alloc] initWithNibName:@"AnyViewController" bundle:nil];
     [self.navigationController pushViewController:c animated:YES];
     [c release];
 }
 
 
-- (void)gridView:(MMGridView *)gridView didDoubleTappedCell:(MMGridViewCell *)cell atIndex:(NSInteger)index
+- (void)gridView:(MMGridView *)gridView didDoubleTappedCell:(MMGridViewCell *)cell atIndex:(NSUInteger)index
 {
     UIAlertView *alert = [[UIAlertView alloc] initWithTitle:nil
                                                     message:[NSString stringWithFormat:@"Cell at index %d was double tapped.", index]
@@ -100,4 +100,11 @@ - (void)gridView:(MMGridView *)gridView didDoubleTappedCell:(MMGridViewCell *)ce
     [alert release];
 }
 
+
+- (void)gridView:(MMGridView *)theGridView changedPageToIndex:(NSUInteger)index
+{
+    NSLog(@"GridView changed page to index: %d", index);
+    NSLog(@"GridView has %d pages", theGridView.numberOfPages);
+}
+
 @end