Build ChatListUI

submodules/LegacyComponents/Sources/TGDraggableCollectionViewFlowLayout.m

@@ -0,0 +1,74 @@
+#import "TGDraggableCollectionViewFlowLayout.h"
+
+@implementation TGDraggableCollectionViewFlowLayout
+
+- (UICollectionViewLayoutAttributes *)initialLayoutAttributesForAppearingItemAtIndexPath:(NSIndexPath *)itemIndexPath
+{
+    if (itemIndexPath == nil)
+        return nil;
+    
+    UICollectionViewLayoutAttributes *attributes = [super initialLayoutAttributesForAppearingItemAtIndexPath:itemIndexPath];
+    attributes.transform3D = CATransform3DMakeTranslation(0, 0, itemIndexPath.row + 1);
+    attributes.zIndex = itemIndexPath.row + 1;
+    
+    return attributes;
+}
+
+- (UICollectionViewLayoutAttributes *)layoutAttributesForItemAtIndexPath:(NSIndexPath *)itemIndexPath
+{
+    if (itemIndexPath == nil)
+        return nil;
+    
+    UICollectionViewLayoutAttributes *attributes = [super layoutAttributesForItemAtIndexPath:itemIndexPath];
+    attributes.transform3D = CATransform3DMakeTranslation(0, 0, 1000 + itemIndexPath.row + 1);
+    attributes.zIndex = 1000 + itemIndexPath.row + 1;
+    
+    return attributes;
+}
+
+- (NSArray *)layoutAttributesForElementsInRect:(CGRect)rect
+{
+    NSArray *originalAttributes = [super layoutAttributesForElementsInRect:rect];
+    
+    if (self.destinationIndexPath == nil)
+    {
+        if (self.hiddenIndexPath == nil)
+            return originalAttributes;
+        
+        for (UICollectionViewLayoutAttributes *layoutAttributes in originalAttributes)
+        {
+            if (layoutAttributes.representedElementCategory != UICollectionElementCategoryCell)
+                continue;
+            
+            if ([layoutAttributes.indexPath isEqual:self.hiddenIndexPath])
+                layoutAttributes.hidden = true;
+        }
+        return originalAttributes;
+    }
+    
+    for (UICollectionViewLayoutAttributes *layoutAttributes in originalAttributes)
+    {
+        if (layoutAttributes.representedElementCategory != UICollectionElementCategoryCell)
+            continue;
+        
+        NSIndexPath *indexPath = layoutAttributes.indexPath;
+        if ([indexPath isEqual:self.hiddenIndexPath])
+            layoutAttributes.hidden = true;
+        
+        if ([indexPath isEqual:self.destinationIndexPath])
+        {
+            layoutAttributes.indexPath = self.sourceIndexPath;
+        }
+        else
+        {
+            if (indexPath.item <= self.sourceIndexPath.item && indexPath.item > self.destinationIndexPath.item)
+                layoutAttributes.indexPath = [NSIndexPath indexPathForItem:indexPath.item - 1 inSection:indexPath.section];
+            else if (indexPath.item >= self.sourceIndexPath.item && indexPath.item < self.destinationIndexPath.item)
+                layoutAttributes.indexPath = [NSIndexPath indexPathForItem:indexPath.item + 1 inSection:indexPath.section];
+        }
+    }
+    
+    return originalAttributes;
+}
+
+@end