我试图让我的核心数据支持的 UITableView 具有重新排序的能力,在实现所有这些委托和提到的核心数据的一些技术之后here https://stackoverflow.com/q/1077568/147564我发现奇怪的行为。点击编辑按钮后,重新排序图标显示得很好,我可以点击它,阴影出现,但是当我尝试将其移动到另一行时,我突然失去焦点,单元格移回其位置。有谁知道这个问题的原因吗?
这是显示问题的视频
这是我的代码
- (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath
{
return YES;
}
in -tableView:moveRowAtIndexPath:toIndexPath
我尝试了下面的代码,只是一个空的实现,但问题仍然存在,所以我认为这不是问题。
- (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)sourceIndexPath toIndexPath:(NSIndexPath *)destinationIndexPath
{
_changeIsUserDriven = YES;
NSUInteger fromIndex = sourceIndexPath.row;
NSUInteger toIndex = destinationIndexPath.row;
NSMutableArray *newsArray = [[self.fetchedResultsController fetchedObjects] mutableCopy];
News *news = [self.fetchedResultsController.fetchedObjects objectAtIndex:fromIndex];
[newsArray removeObject:news];
[newsArray insertObject:news atIndex:toIndex];
int i = 1;
for (News *n in newsArray) {
n.displayOrder = [NSNumber numberWithInt:i++];
}
[self saveContext];
_changeIsUserDriven = NO;
}
FetchedResultsController 委托
- (void)controllerWillChangeContent:(NSFetchedResultsController *)controller
{
if (_changeIsUserDriven) {
return;
}
[self.tableView beginUpdates];
}
- (void)controller:(NSFetchedResultsController *)controller didChangeSection:(id <NSFetchedResultsSectionInfo>)sectionInfo
atIndex:(NSUInteger)sectionIndex forChangeType:(NSFetchedResultsChangeType)type
{
if (_changeIsUserDriven) {
return;
}
switch(type) {
case NSFetchedResultsChangeInsert:
[self.tableView insertSections:[NSIndexSet indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationFade];
break;
case NSFetchedResultsChangeDelete:
[self.tableView deleteSections:[NSIndexSet indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationFade];
break;
}
}
- (void)controller:(NSFetchedResultsController *)controller didChangeObject:(id)anObject
atIndexPath:(NSIndexPath *)indexPath forChangeType:(NSFetchedResultsChangeType)type
newIndexPath:(NSIndexPath *)newIndexPath
{
if (_changeIsUserDriven) {
return;
}
UITableView *tableView = self.tableView;
switch(type) {
case NSFetchedResultsChangeInsert:
[tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath] withRowAnimation:UITableViewRowAnimationFade];
break;
case NSFetchedResultsChangeDelete:
[tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
break;
case NSFetchedResultsChangeUpdate:
[self configureCell:[tableView cellForRowAtIndexPath:indexPath] atIndexPath:indexPath];
break;
case NSFetchedResultsChangeMove:
[tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
[tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath]withRowAnimation:UITableViewRowAnimationFade];
break;
}
}
- (void)controllerDidChangeContent:(NSFetchedResultsController *)controller
{
if (_changeIsUserDriven) {
return;
}
[self.tableView endUpdates];
}
最后我发现问题是因为我使用的外部库 IIViewDeckController,删除后问题就消失了。
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