Added horizontal paged strategy

gmoledina · Dec 11, 2011 · 9ee51dd · 9ee51dd
1 parent 4161cdd
commit 9ee51dd
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Showing 5 changed files with 330 additions and 55 deletions.
diff --git a/GMGridView/API/GMGridView.h b/GMGridView/API/GMGridView.h
@@ -82,7 +82,7 @@ typedef enum
 - (void)removeObjectAtIndex:(NSInteger)index;
 - (void)reloadObjectAtIndex:(NSInteger)index;
 - (void)swapObjectAtIndex:(NSInteger)index1 withObjectAtIndex:(NSInteger)index2;
-- (void)scrollToObjectAtIndex:(NSInteger)index;
+- (void)scrollToObjectAtIndex:(NSInteger)index animated:(BOOL)animated;
 
 @end
 

diff --git a/GMGridView/API/GMGridView.m b/GMGridView/API/GMGridView.m
@@ -273,6 +273,8 @@ - (void)setMainSuperView:(UIView *)mainSuperView
 - (void)setLayoutStrategy:(id<GMGridViewLayoutStrategy>)layoutStrategy
 {
     _layoutStrategy = layoutStrategy;
+
+    _scrollView.pagingEnabled = [[self.layoutStrategy class] requiresEnablingPaging];
     [self setNeedsLayout];
 }
 
@@ -1073,8 +1075,7 @@ - (void)recomputeSize
 
     CGSize contentSize = [self.layoutStrategy contentSize];
 
-    _minPossibleContentOffset = CGPointMake(-1 * (_scrollView.contentInset.left), 
-                                            -1 * (_scrollView.contentInset.top));
+    _minPossibleContentOffset = CGPointMake(0, 0);
     _maxPossibleContentOffset = CGPointMake(contentSize.width - _scrollView.bounds.size.width + _scrollView.contentInset.right, 
                                             contentSize.height - _scrollView.bounds.size.height + _scrollView.contentInset.bottom);
 
@@ -1270,12 +1271,11 @@ - (void)reloadObjectAtIndex:(NSInteger)index
 
     currentView.tag = kTagOffset - 1;
 
-    // Better performance animating ourselves instead of using animated:YES in scrollRectToVisible
     [UIView animateWithDuration:kDefaultAnimationDuration 
                           delay:0
                         options:kDefaultAnimationOptions
                      animations:^{
-                         [_scrollView scrollRectToVisible:cell.frame animated:NO];
+                         [self scrollToObjectAtIndex:index animated:NO];
                          currentView.alpha = 0;
                          cell.alpha = 1;
                      } 
@@ -1288,18 +1288,40 @@ - (void)reloadObjectAtIndex:(NSInteger)index
     [self setSubviewsCacheAsInvalid];
 }
 
-- (void)scrollToObjectAtIndex:(NSInteger)index
+- (void)scrollToObjectAtIndex:(NSInteger)index animated:(BOOL)animated
 {
-    NSAssert((index >= 0 && index < _numberTotalItems), @"Invalid index");
-
+    index = MAX(0, index);
+    index = MIN(index, _numberTotalItems);
+
     CGPoint origin = [self.layoutStrategy originForItemAtPosition:index];
+    CGRect scrollToRect = CGRectMake(origin.x, origin.y, _itemSize.width, _itemSize.height);
+
+    if (_scrollView.pagingEnabled) 
+    {
+        CGPoint originScroll = CGPointZero;
+
+        CGSize pageSize = CGSizeMake(_scrollView.bounds.size.width  - _scrollView.contentInset.left - _scrollView.contentInset.right, 
+                                     _scrollView.bounds.size.height - _scrollView.contentInset.top  - _scrollView.contentInset.bottom);
+
+        while (originScroll.x + pageSize.width < origin.x) 
+        {
+            originScroll.x += pageSize.width;
+        }
+
+        while (originScroll.y + pageSize.height < origin.y) 
+        {
+            originScroll.y += pageSize.height;
+        }
+
+        scrollToRect = CGRectMake(originScroll.x, originScroll.y, pageSize.width, pageSize.height);
+    }
 
     // Better performance animating ourselves instead of using animated:YES in scrollRectToVisible
-    [UIView animateWithDuration:kDefaultAnimationDuration 
+    [UIView animateWithDuration:animated ? kDefaultAnimationDuration : 0
                           delay:0
                         options:kDefaultAnimationOptions
                      animations:^{
-                         [_scrollView scrollRectToVisible:CGRectMake(origin.x, origin.y, _itemSize.width, _itemSize.height) animated:NO];
+                         [_scrollView scrollRectToVisible:scrollToRect animated:NO];
                      } 
                      completion:^(BOOL finished){
                      }
@@ -1311,12 +1333,9 @@ - (void)insertObjectAtIndex:(NSInteger)index
     NSAssert((index >= 0 && index <= _numberTotalItems), @"Invalid index specified");
 
     GMGridViewCell *cell = nil;
-    BOOL isInsertedObjectVisible = NO;
 
     if (index >= self.firstPositionLoaded && index <= self.lastPositionLoaded) 
-    {
-        isInsertedObjectVisible = YES;
-
+    {        
         cell = [self newItemSubViewForPosition:index];
 
         for (int i = index; i < _numberTotalItems; i++)
@@ -1331,23 +1350,17 @@ - (void)insertObjectAtIndex:(NSInteger)index
     _numberTotalItems++;
     [self recomputeSize];
 
-    // We cant use cell.frame as it might not be loaded yet
-    CGPoint newObjectOrigin = [self.layoutStrategy originForItemAtPosition:index];
-
-    // Better performance animating ourselves instead of using animated:YES in scrollRectToVisible
     [UIView animateWithDuration:kDefaultAnimationDuration 
                           delay:0
                         options:kDefaultAnimationOptions
                      animations:^{
-                         [_scrollView scrollRectToVisible:CGRectMake(newObjectOrigin.x, newObjectOrigin.y, _itemSize.width, _itemSize.height) animated:NO];
+                         [self scrollToObjectAtIndex:index animated:NO];
                      } 
                      completion:^(BOOL finished){
                          [self setNeedsLayout];
                      }
      ];
 
-
-
     [self setSubviewsCacheAsInvalid];
 }
 
@@ -1366,17 +1379,14 @@ - (void)removeObjectAtIndex:(NSInteger)index
     cell.tag = kTagOffset - 1;
     _numberTotalItems--;
 
-    CGPoint origin = [self.layoutStrategy originForItemAtPosition:index];
-
-    // Better performance animating ourselves instead of using animated:YES in scrollRectToVisible
     [UIView animateWithDuration:kDefaultAnimationDuration 
                           delay:0
                         options:kDefaultAnimationOptions
                      animations:^{
                          cell.contentView.alpha = 0.3;
                          cell.alpha = 0;
 
-                         [_scrollView scrollRectToVisible:CGRectMake(origin.x, origin.y, _itemSize.width, _itemSize.height) animated:NO];
+                         [self scrollToObjectAtIndex:index animated:NO];
 
                          [self recomputeSize];
                      } 
@@ -1424,11 +1434,11 @@ - (void)swapObjectAtIndex:(NSInteger)index1 withObjectAtIndex:(NSInteger)index2
                      animations:^{
                          if (!CGRectIntersectsRect(view2.frame, visibleRect)) 
                          {
-                             [_scrollView scrollRectToVisible:view1.frame animated:NO];
+                             [self scrollToObjectAtIndex:index1 animated:NO];
                          }
                          else if (!CGRectIntersectsRect(view1.frame, visibleRect)) 
                          {
-                             [_scrollView scrollRectToVisible:view2.frame animated:NO];
+                             [self scrollToObjectAtIndex:index2 animated:NO];
                          }
                      } 
                      completion:^(BOOL finished){

diff --git a/GMGridView/API/GMGridViewLayoutStrategies.h b/GMGridView/API/GMGridViewLayoutStrategies.h
@@ -35,7 +35,8 @@
 
 typedef enum {
     GMGridViewLayoutVertical = 0,
-    GMGridViewLayoutHorizontal
+    GMGridViewLayoutHorizontal,
+    GMGridViewLayoutHorizontalPaged
 } GMGridViewLayoutStrategyType;
 
 
@@ -57,6 +58,8 @@ typedef enum {
 
 @protocol GMGridViewLayoutStrategy <NSObject>
 
++ (BOOL)requiresEnablingPaging;
+
 - (GMGridViewLayoutStrategyType)type;
 
 // Setup
@@ -149,4 +152,22 @@ typedef enum {
 @end
 
 
+//////////////////////////////////////////////////////////////
+#pragma mark - Horizontal strategy
+//////////////////////////////////////////////////////////////
+
+@interface GMGridViewLayoutHorizontalPagedStrategy : GMGridViewLayoutHorizontalStrategy <GMGridViewLayoutStrategy>
+{
+    @protected
+    NSInteger _numberOfItemsPerRow;
+    NSInteger _numberOfItemsPerPage;
+    NSInteger _numberOfPages;
+}
+
+@property (nonatomic, readonly) NSInteger numberOfItemsPerRow;
+@property (nonatomic, readonly) NSInteger numberOfItemsPerPage;
+@property (nonatomic, readonly) NSInteger numberOfPages;
+
+@end
+