我有UITableViewController靜態可編輯單元格。在我的UITableViewController我做CoreData對象,像這樣:NSFetchedResultsController新對象
- (User*)user {
if (_user == nil) {
_user = [NSEntityDescription insertNewObjectForEntityForName:TABLE_USER inManagedObjectContext:self.managedObjectContext];
NSError* error;
[self.managedObjectContext save:&error];
if (error != nil) {
abort();
}
}
return _user;
}
我想在NSFetchedResultsController對象,將在一個表中顯示其字段,然後保存對象。 我正在嘗試:
- (NSFetchedResultsController *)fetchedResultsController
{
if (_fetchedResultsController != nil) {
return _fetchedResultsController;
}
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
// Edit the entity name as appropriate.
NSEntityDescription *entity = [NSEntityDescription entityForName:TABLE_USER_PROFILE inManagedObjectContext:self.managedObjectContext];
[fetchRequest setEntity:entity];
// Set the batch size to a suitable number.
[fetchRequest setFetchBatchSize:20];
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"lastName" ascending:NO];
NSArray *sortDescriptors = @[sortDescriptor];
NSPredicate* pred = [NSPredicate predicateWithFormat:@"%@ = %@", TABLE_USER, self.user];
[fetchRequest setPredicate:pred];
[fetchRequest setSortDescriptors:sortDescriptors];
NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:nil cacheName:TABLE_USER];
aFetchedResultsController.delegate = self;
self.fetchedResultsController = aFetchedResultsController;
NSError *error = nil;
if (![self.fetchedResultsController performFetch:&error]) {
abort();
}
return _fetchedResultsController;
}
但它沒有奏效。我得到空fetchedResultsController。
「NSPredicate」和「TABLE_USER」怎麼辦? –
這是靜態字符串等於'@「用戶」' –
和'self.user'呢?它是一個對象還是一個字符串?你還可以分享'NSFetchRequest'嗎?最後,也許我不明白,但你想知道爲什麼查詢不檢索任何結果,我錯了嗎?謝謝。 –