Double tap UISearchBar with search delegate on iOS

问题:

We have a search bar in the table header. When the user taps on it twice quickly on iOS 7, it disappears. Does anyone have any suggestions what we are doing wrong?

回答1:

After lots of trial and errors, I found that when searchDisplayController ends search, searchbar gets disappear, so I have reinserted the searchbar to table header and it worked for me.

- (void)searchDisplayControllerDidEndSearch:(UISearchDisplayController *)controller
{
    self.searchingFetchedResultsController = nil;
    if (floor(NSFoundationVersionNumber) > NSFoundationVersionNumber_iOS_6_1) {
        [self.tableView insertSubview:self.searchDisplayController.searchBar aboveSubview:self.tableView];
    }
    return;
}

Hope this helps.

回答2:

(I posted this same answer to Troubles with UISearchBar \ UISearchDisplayViewController, which seems like a duplicate of this question.)

I encountered the same issue, and noticed that searchDisplayControllerDidEndSearch was being called twice. The first time, the superview of self.searchDisplayController.searchBar is the UITableView, and the second time it's still a UIView.

With Priya's answer, I worry about unintended consequences or unneeded overhead from re-inserting the subview every time the search bar is double-tapped, and I also worry about it breaking with future iOS versions. Fortunately, we can take advantage of the superview strangeness like this:

- (void)searchDisplayControllerDidEndSearch:(UISearchDisplayController *)controller {
    if (self.tableView != self.searchDisplayController.searchBar.superview) {
        [self.tableView insertSubview:self.searchDisplayController.searchBar aboveSubview:self.tableView];
    }
}

If I had to guess what was happening, the UISearchBar is automatically creating a temporary UIView as its superview when it's active – this is the view seen when the search is being performed. While the UISearchBar is being dismissed, the superview gets set back to be the UITableView it had before, unless it gets dismissed so quickly that it was never properly initialized, in which case it cleans up improperly and the UITableView never gets the UISearchBar back as its child.

This solution still isn't ideal, and I think Apple must be doing something different in its own apps because their search bar UX feels a bit better. I think it would be better not to handle the second tap in the first place until the UISearchBar was ready. I tried using the other UISearchBarDelegate methods to do this, but I couldn't find an appropriate hook to override the current behavior.