-[UICollectionView beginInteractiveMovementForItemAtIndexPath:] doesn't update moved cell when starting on the same position where the last moved start

Originator:avedesk
Number:rdar://28074111 Date Originated:30-Aug-2016 02:23 PM
Status:Open Resolved:
Product:iOS SDK Product Version:9.3.5
Classification:Other Bug Reproducible:Always
 
Summary:
-[UICollectionView beginInteractiveMovementForItemAtIndexPath:] doesn't update the cell being moved with the layout attributes from `-layoutAttributesForInteractivelyMovingItemAtIndexPath:` directly, IF the move operation starts on the same point as the previous operation ended.

Steps to Reproduce:
1. Call -[UICollectionView beginInteractiveMovementForItemAtIndexPath:CGPoint(x,y)]
2. Call -[UICollectionView updateInteractiveMovementTargetPosition:CGPoint(someOtherX, someOtherY)]
3. Call -[UICollectionView endInteractiveMovement]
4. Call -[UICollectionView beginInteractiveMovementForItemAtIndexPath:CGPoint(someOtherX, someOtherY)]
5. Call -[UICollectionView updateInteractiveMovementTargetPosition:CGPoint(someOtherX, someOtherY)]

Expected Results:
- The cell being moved gets updated with new layout attributes as returned by -[UICollectionViewLayout layoutAttributesForInteractivelyMovingItemAtIndexPath:]

Actual Results:
- The cell doesn't get updated, until -[UICollection updateInteractiveMovementTargetPosition:] is called with a different point again 

Regression:


Notes:
It seems -[UICollectionView updateInteractiveMovementTargetPosition:] does something like:
```
if(CGPointEqualToPoint(_previousPoint, point) == YES)
return;

_previousPoint = point;
// continue updating cells
```

And that it feels to clear the previous point when beginInteractiveMovementForItemAtIndexPath: is called.

Comments


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