我正在尝试使用NSCollectionView
和NSCollectionViewDiffableDataSource
创建具有动态数目的节的NSCollectionViewCompositionalLayout
。
收集视图用于显示搜索结果,部分的数量取决于找到的结果的类型和数量。每个部分使用不同的布局显示其内容类型。
数据源被声明为NSCollectionViewDiffableDataSource<String,SearchResult>
,其中SearchResult
是使用Hashable
实现UUID()
的类。结果为零的部分不是空的,而是在集合视图中不存在。
显示视图控制器后,我会清除现有搜索结果:
func clearSearchResults(animate: Bool) {
let snapshot = NSDiffableDataSourcesnapshot<String,SearchResult>()
dataSource.apply(snapshot,animatingDifferences: animate)
}
当执行搜索时,我尝试为找到的每种结果类型在收集视图中添加一个部分:
// Code that performs the search
var snapshot = NSDiffableDataSourcesnapshot<String,SearchResult>()
// If I append more than one section an exception is thrown in apply():
// snapshot.appendSections([ViewController.trackSection,ViewController.albumSection])
snapshot.appendSections([ViewController.trackSection])
snapshot.appendItems(tracks,toSection: ViewController.trackSection)
// This also causes an exception in apply():
// snapshot.appendSections([ViewController.albumSection])
// snapshot.appendItems(albums,toSection: ViewController.albumSection)
dataSource.apply(snapshot,animatingDifferences: true)
堆栈跟踪为:
2019-11-10 13:34:29.883728-0600 DiffableTest[64931:1820050] [General] An uncaught exception was raised
2019-11-10 13:34:29.883813-0600 DiffableTest[64931:1820050] [General] -[NSCollectionView insertSections:] Section index 1 out of bounds
2019-11-10 13:34:29.883937-0600 DiffableTest[64931:1820050] [General] (
0 CoreFoundation 0x00007fff33a98f53 __exceptionPreprocess + 250
1 libobjc.A.dylib 0x00007fff69b5e835 objc_exception_throw + 48
2 CoreFoundation 0x00007fff33a98da9 +[NSException raise:format:] + 189
3 UIFoundation 0x00007fff6469fd5b -[_NSCollectionViewCore insertSections:] + 267
4 UIFoundation 0x00007fff6465dd5e -[_NSDiffableDataSourceViewUpdater _performNSCollectionViewInsertUpdate:] + 222
5 UIFoundation 0x00007fff6465db33 -[_NSDiffableDataSourceViewUpdater _performViewUpdates:] + 594
6 AppKit 0x00007fff3156d8e8 __58-[NSCollectionView performBatchUpdates:completionHandler:]_block_invoke + 21
7 UIFoundation 0x00007fff646aabe5 -[_NSCollectionViewCore _performBatchUpdates:completion:invalidationContext:tentativelyForReordering:animator:] + 323
8 UIFoundation 0x00007fff646aaa7f -[_NSCollectionViewCore _performBatchUpdates:completion:invalidationContext:tentativelyForReordering:] + 90
9 UIFoundation 0x00007fff646aaa02 -[_NSCollectionViewCore _performBatchUpdates:completion:invalidationContext:] + 74
10 UIFoundation 0x00007fff646aa957 -[_NSCollectionViewCore performBatchUpdates:completion:] + 53
11 AppKit 0x00007fff3156d7f4 -[NSCollectionView performBatchUpdates:completionHandler:] + 282
12 UIFoundation 0x00007fff6465d2ee -[_NSDiffableDataSourceViewUpdater _performUpdateWithCollectionViewUpdateItems:dataSourcesnapshotter:updateHandler:completion:] + 528
13 UIFoundation 0x00007fff646c72a2 -[__NSDiffableDataSource _commitNewDataSource:withViewUpdates:completion:] + 265
14 UIFoundation 0x00007fff646c1cb9 __66-[__NSDiffableDataSource applyDifferencesFromsnapshot:completion:]_block_invoke.259 + 190
15 UIFoundation 0x00007fff646c1fd2 __66-[__NSDiffableDataSource applyDifferencesFromsnapshot:completion:]_block_invoke.284 + 170
16 libdispatch.dylib 0x000000010039e78f _dispatch_client_callout + 8
17 libdispatch.dylib 0x00000001003af4cb _dispatch_lane_barrier_sync_invoke_and_complete + 135
18 UIFoundation 0x00007fff646c172d -[__NSDiffableDataSource applyDifferencesFromsnapshot:completion:] + 842
19 UIFoundation 0x00007fff64765417 +[_NSUIAnimator performWithAnimation:] + 90
20 UIFoundation 0x00007fff646c2939 -[__NSDiffableDataSource applyDifferencesFromsnapshot:animatingDifferences:completion:] + 158
21 libswiftAppKit.dylib 0x00007fff6a2f6bb3 $s6AppKit34NSCollectionViewDiffableDataSourceC5apply_20animatingDifferences10completionyAA010NSDiffablefG8snapshotVyxq_G_SbyycSgtF + 211
22 DiffableTest 0x0000000100005c73 $s12DiffableTest14ViewControllerC13performSearchyyyXlSgF + 3059
我是否以某种方式滥用了API?
有关示例项目,请参见https://github.com/sbooth/DiffableTest。