我正在使用UICollection视图，并希望对其数据源的更改进行动画处理。新数据源与旧数据共享很多项目，我想动画插入新项目并删除不再存在于数据源中的项目，同时保持所有其他单元格完好无损：
目前：[1,2,8,9] 更新：[1,2,3,9] 更改：插入3，删除8
是否有使用动画交换UICollectionView的数据源的示例？
我试过这个，这会导致集合视图闪烁，但是没有播放动画：
[self.collectionView performBatchUpdates:^{
[self.collectionView reloadSections:[NSIndexSet indexSetWithIndex:0]];
} completion:^(BOOL finished) {
}];
此方法会抱怨项目数量不匹配：
-(void)setDatasource:(NSMutableArray *)datasource
{
NSMutableArray* _datasourceBackup = _datasource;
//find out what is being added and deleted
NSMutableArray* itemsToDelete = [NSMutableArray arrayWithArray:_datasource];
DLog(@"delete raw: %lu", (unsigned long)itemsToDelete.count);
[itemsToDelete removeObjectsInArray:datasource];
DLog(@"delete filtered: %lu", (unsigned long)itemsToDelete.count);
NSMutableArray* itemsToAdd = [NSMutableArray arrayWithArray:datasource];
DLog(@"add raw: %lu", (unsigned long)itemsToAdd.count);
[itemsToAdd removeObjectsInArray:_datasource];
DLog(@"add filtered: %lu", (unsigned long)itemsToAdd.count);
//1 update datasource
_datasource = datasource;
if(_datasourceBackup.count == 0)
{
//original load
[self.collectionView reloadData];
}else
{
[self.collectionView performBatchUpdates:^{
//convert items to add/delete into index paths and give them to collection view to animate
NSMutableArray* indexPathsToDelete = [NSMutableArray array];
for(NSString* identifier in itemsToDelete)
{
NSInteger index = [_datasourceBackup indexOfObject:identifier];
[indexPathsToDelete addObject: [NSIndexPath indexPathForRow:index inSection:0]];
}
if(indexPathsToDelete.count > 0 )
{
[self.collectionView deleteItemsAtIndexPaths:indexPathsToDelete];
}
NSMutableArray* indexPathsToInsert = [NSMutableArray arrayWithCapacity:itemsToAdd.count];
for(NSString* identifier in itemsToAdd)
{
NSInteger index = [_datasource indexOfObject:identifier];
[indexPathsToInsert addObject: [NSIndexPath indexPathForRow:index inSection:0]];
}
if(indexPathsToInsert.count > 0 )
{
[self.collectionView insertItemsAtIndexPaths:indexPathsToInsert];
}
} completion:nil];
}
}