UISearchController in UITableViewController disappears

Question

Created Aug ’16

Replies 3

Boosts 0

Views 1.2k

Participants 3

I'm using NSFetchedResultsController for the tableview display the results returned by Core Data.

Use UISearchController to search. I have the following problem: sometimes, if I search while the tableView is being updated, the search bar disappears.

The table view is in a navigation controller.

- (void)viewDidLoad {
    [super viewDidLoad];
     ...

    [self.view setMultipleTouchEnabled:NO];
    [self.tableView setMultipleTouchEnabled:NO];
    [self.tableView setSeparatorStyle:UITableViewCellSeparatorStyleNone];
    [self.tableView setContentInset:UIEdgeInsetsMake(0, 0, 44, 0)];

    _searchController = [[UISearchController alloc] initWithSearchResultsController:nil];
    self.searchController.searchResultsUpdater = self;
    self.searchController.delegate = self;
    self.searchController.dimsBackgroundDuringPresentation = NO; /
    self.searchController.hidesNavigationBarDuringPresentation = NO;

    [self.searchController.searchBar sizeToFit];
    self.searchController.searchBar.delegate = self; /
    self.definesPresentationContext = YES;

    self.tableView.tableHeaderView = self.searchController.searchBar;
     [self fetchedResultsController];
     ...
}

Any idea what may be wrong? Thanks.

Boost

Answer 1

junkpile OP

Aug ’16

I don't know, but Apple's Mail app does the same thing (search bar goes blank sometimes) so you're not alone.

0

Answer 2

vicramrol OP

Aug ’16

It seems that the problem lies in the beginUpdates and methods endUpdates. These methods interfere in any way in the animation of the search bar. I would like to understand the cause.

- (void)controllerWillChangeContent:(NSFetchedResultsController *)controller {

[self.tableView beginUpdates];

}

- (void)controller:(NSFetchedResultsController *)controller didChangeObject:(id)anObject atIndexPath:(NSIndexPath *)indexPath forChangeType:(NSFetchedResultsChangeType)type newIndexPath:(NSIndexPath *)newIndexPath {

UITableView *tableView = self.tableView;

switch(type) {

case NSFetchedResultsChangeInsert:

[tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath] withRowAnimation:UITableViewRowAnimationTop];

break;

case NSFetchedResultsChangeDelete:

[tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationTop];

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 {

[self.tableView endUpdates];

}

To solve the problem I deleted the above code and I used [self.tableView reloadData];

- (void)controller:(NSFetchedResultsController *)controller didChangeObject:(id)anObject atIndexPath:(NSIndexPath *)indexPath forChangeType:(NSFetchedResultsChangeType)type newIndexPath:(NSIndexPath *)newIndexPath {

[self.tableView reloadData];

}

0

Answer 3

bbousquet OP

Sep ’16

Had a similar issue with a plain UISearchController. I was updating the UITableView (with begin/endUpdates) during updateSearchResults. It seems if this is done while the search controller is animating we experience the visual glitch.

Note that this occurs as soon as begin/endUpdates is used - regardless of whether or not the animation block contains any row animations. I fixed it by tweaking my code to avoid empty begin/endUpdates blocks.

0