我想阅读用户或应用程序在 iCloud 的移动文档目录（在 ~/Library/Mobile Documents 下的 Lion 中找到的目录）中创建的所有目录的列表。这是该目录的外观示例：
我尝试了以下代码，但我运行的查询将不包含任何代表我的文件夹的对象（使用 NSPredicate predicateWithFormat:@"%K.pathExtension = ''", NSMetadataItemFSNameKey）。如果我对 txt 文件运行查询（使用@"%K ENDSWITH '.txt'", NSMetadataItemFSNameKey），我将分别为 txt 文件返回 5 个对象。因此，寻找 txt 文件有效，但不适用于目录。通读文档，我注意到 Apple 建议使用 NSFileWrapper（文件包）而不是目录。iCloud 是否无法处理/检测用户或应用程序创建的目录？
这是我的代码：
-(void)loadDocument {
NSMetadataQuery *query = [[NSMetadataQuery alloc] init];
_query = query;
//Search all files in the Documents directories of the application’s iCloud container directories:
[query setSearchScopes:[NSArray arrayWithObject:NSMetadataQueryUbiquitousDocumentsScope]];
NSPredicate *pred = [NSPredicate predicateWithFormat:@"%K.pathExtension = ''", NSMetadataItemFSNameKey];
[query setPredicate:pred];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(queryDidFinishGathering:) name:NSMetadataQueryDidFinishGatheringNotification object:query];
[query startQuery];
}
- (void)queryDidFinishGathering:(NSNotification *)notification {
NSMetadataQuery *query = [notification object];
[query disableUpdates]; // You should invoke this method before iterating over query results that could change due to live updates.
[query stopQuery]; // You would call this function to stop a query that is generating too many results to be useful but still want to access the available results.
[self loadData:query];
[[NSNotificationCenter defaultCenter] removeObserver:self name:NSMetadataQueryDidFinishGatheringNotification object:query];
_query = nil; // we're done with it
}
- (void)loadData:(NSMetadataQuery *)query {
NSLog(@"Query count %i", [query resultCount]);
for (int i=0; i < [query resultCount]; i++) {
NSMetadataItem *item = [query resultAtIndex:i];
NSURL *url = [item valueForAttribute:NSMetadataItemURLKey];
NSLog(@"%i.URL: %@", i, url);
}
}