CMSetController 是一个用于 NSSet 的 KVO 控制器，它在没有 Core Data 的情况下表现类似于 NSFetchedResultController。
给定一个对象，它有一个包含您希望绑定到表视图的对象的 NSSet 属性，提供（与 NSFetchedResultController 很相似）
控制器将提供一组部分和对象以填充 UITableView 数据源。当集合中的对象发生变化时，它还将调用回委托类以更新、插入、删除、重新排序和部分更改。
在配置绑定项视图时配置 CMSetController。如果您没有包含集合的模型对象，请使集合成为您控制器的属性。
// watch for changes to either the "name" or "favoriteColor" properties
NSArray *paths = @[@"name", @"favoriteColor"];
// sort by "favoriteColor" (first sort must match section key path, if any) then "name"
NSArray *sorts = @[[NSSortDescriptor sortDescriptorWithKey:@"favoriteColor" ascending:YES], [NSSortDescriptor sortDescriptorWithKey:@"name" ascending:YES]];
// observe the "friends" set property of the "self.document" object using the key paths and
// sorts setup above, group by "favoriteColor" into sections, and receive delegate callbacks
// as the set changes
_setController = [[CMSetController alloc] initWithObserved:self.document
setKeyPath:@"friends"
keyPaths:paths
sectionNameKeyPath:@"favoriteColor"
sortDescriptors:sorts
delegate:self];
NSError *error;
if (![_setController performQuery:&error]) {
NSLog(@"oops - %@", error);
abort();
}
[self.tableView reloadData];就像使用 NSFetchedResultController 一样填充表视图
#pragma mark - Table view
- (void)configureCell:(UITableViewCell *)cell atIndexPath:(NSIndexPath *)indexPath
{
CMFriend *friend = [[[[_setController sections] objectAtIndex:indexPath.section] objects] objectAtIndex:indexPath.row];
cell.textLabel.text = friend.name;
cell.detailTextLabel.text = friend.favoriteColor;
}
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return [[_setController sections] count];
}
- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section
{
return [[[_setController sections] objectAtIndex:section] name];
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return [[[_setController sections] objectAtIndex:section] numberOfObjects];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
[self configureCell:cell atIndexPath:indexPath];
return cell;
}如果您实现了 CMSetControllerDelegate，您将获得针对更新表视图定制的回调
#pragma mark - Query Delegate
- (void)controllerWillChangeContent:(CMSetController *)controller
{
[self.tableView beginUpdates];
}
- (void)controller:(CMSetController *)controller didChangeSection:(id<CMSetControllerSectionInfo>)sectionInfo atIndex:(NSUInteger)index forChangeType:(CMSetControllerChangeType)type
{
NSIndexSet *indexSet = [NSIndexSet indexSetWithIndex:index];
if (type == CMSetControllerChangeInsert)
[self.tableView insertSections:indexSet withRowAnimation:UITableViewRowAnimationAutomatic];
else
[self.tableView deleteSections:indexSet withRowAnimation:UITableViewRowAnimationAutomatic];
}
- (void)controller:(CMSetController *)controller didChangeObject:(id)object atIndexPath:(NSIndexPath *)indexPath forChangeType:(CMSetControllerChangeType)type newIndexPath:(NSIndexPath *)newIndexPath
{
switch (type) {
case CMSetControllerChangeInsert:
[self.tableView insertRowsAtIndexPaths:@[newIndexPath]
withRowAnimation:UITableViewRowAnimationAutomatic];
break;
case CMSetControllerChangeDelete:
[self.tableView deleteRowsAtIndexPaths:@[indexPath]
withRowAnimation:UITableViewRowAnimationAutomatic];
break;
case CMSetControllerChangeUpdate:
[self.tableView reloadRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];
break;
case CMSetControllerChangeMove:
[self.tableView deleteRowsAtIndexPaths:@[indexPath]
withRowAnimation:UITableViewRowAnimationFade];
[self.tableView insertRowsAtIndexPaths:@[newIndexPath]
withRowAnimation:UITableViewRowAnimationFade];
break;
default:
break;
}
}
- (void)controllerDidChangeContent:(CMSetController *)controller
{
[self.tableView endUpdates];
}CMSetController 在 MIT 许可下发布。有关更多详细信息，请参阅 LICENSE 文件。