iPhone - UITableView - lost data if i go back

Question

Hello!

I have a TabBar, NavBar, SearchBar with ScopeBar on my screen. I can search data via a remote server and list the content. So I have a NSMutableArray listContent and a filteredListContent like in the example of Apple (TableSearch - http://developer.apple.com/iphone/library/samplecode/TableSearch/index.html):

Now I added in

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath

these line:

    testDetailViewController *testDetailViewController = [[TestDetailViewController alloc] initWithNibName:@"TestDetailView" bundle:[NSBundle mainBundle]];
    testDetailViewController.title = testClass.name;
    testDetailViewController.myKey = testClass.keyId;
    [[self navigationController] pushViewController:testDetailViewController animated:YES];
    [testDetailViewController release];
    testDetailViewController = nil;

Because of the NavigationBar, there is a "back" button. If I click this button, the TableView is empty, no matches/hits. What I have to do, so the content will still be there?

Does anyone know?

Thanks a lot in advance & Best Regards.

Source Code:

@implementation SearchViewController

@synthesize listContent, filteredListContent, savedSearchTerm, savedScopeButtonIndex, searchWasActive;

- (void)viewDidLoad {
    // restore search settings if they were saved in didReceiveMemoryWarning.
    if (self.savedSearchTerm) {
        [self.searchDisplayController setActive:self.searchWasActive];
        [self.searchDisplayController.searchBar setSelectedScopeButtonIndex:self.savedScopeButtonIndex];
        [self.searchDisplayController.searchBar setText:savedSearchTerm];
        self.savedSearchTerm = nil;
    }
}

- (void)viewDidUnload {
    // Save the state of the search UI so that it can be restored if the view is re-created.
    self.searchWasActive = [self.searchDisplayController isActive];
    self.savedSearchTerm = [self.searchDisplayController.searchBar text];
    self.savedScopeButtonIndex = [self.searchDisplayController.searchBar selectedScopeButtonIndex];
    self.filteredListContent = nil;
}

- (void)dealloc {
    [listContent release];
    [filteredListContent release];
    [super dealloc];
}

- (void)setData {
    self.listContent = [NSMutableArray arrayWithCapacity:3];
    [self.listContent addObject:[SearchObjects itemWithType:@"AAA" name:@"Test1"]];
    [self.listContent addObject:[SearchObjects itemWithType:@"BBB" name:@"Test2"]];
    [self.listContent addObject:[SearchObjects itemWithType:@"BBB" name:@"Test3"]];

    // create a filtered list
    self.filteredListContent = [NSMutableArray arrayWithCapacity:[self.listContent count]];
    [self.tableView reloadData];
    self.tableView.scrollEnabled = YES;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    //If the requesting table view is the search display controller's table view, return the count of the filtered list, otherwise return the count of the main list.
    if (tableView == self.searchDisplayController.searchResultsTableView) {
        return [self.filteredListContent count];
    } else {
        return [self.listContent count];
    }
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    static NSString *kCellID = @"cellID";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:kCellID];
    if (cell == nil) {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:kCellID] autorelease];
        cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
    }

    /* If the requesting table view is the search display controller's table view, configure the cell using the filtered content, otherwise use the main list. */
    SearchObjects *searchObject = nil;
    if (tableView == self.searchDisplayController.searchResultsTableView) {
        searchObject = [self.filteredListContent objectAtIndex:indexPath.row];
    } else {
        searchObject = [self.listContent objectAtIndex:indexPath.row];
    }
    cell.textLabel.text = searchObject.name;
    return cell;
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    // HERE IS THE SOURCE CODE FOR PUSHING TO THE NEXT VIEW
}

- (void)searchBarSearchButtonClicked:(UISearchBar *)searchBar {
    // DO SOME CALCULATIONS… AND THE setData METHOD IS CALLED
}

- (void)filterContentForSearchText:(NSString*)searchText scope:(NSString*)scope {
    /* Update the filtered array based on the search text and scope. */
    [self.filteredListContent removeAllObjects]; // First clear the filtered array.

    /* Search the main list for whose type matches the scope (if selected) and whose name matches searchText; add items that match to the filtered array. */
    for (SearchObjects *searchObject in listContent) {
        if ([scope isEqualToString:@"All"] || [searchObject.type isEqualToString:scope]) {
        NSComparisonResult result = [searchObject.name compare:searchText options:(NSCaseInsensitiveSearch|NSDiacriticInsensitiveSearch) range:NSMakeRange(0, [searchText length])];
            if (result == NSOrderedSame) {
                [self.filteredListContent addObject:searchObject];
            }
        }
    }
}

- (void)filterContentForScope:(NSString*)scope {
    /* Update the filtered array based on the search text and scope. */
    [self.filteredListContent removeAllObjects]; // First clear the filtered array.

    /* Search the main list for whose type matches the scope (if selected); add items that match to the filtered array. */
    for (SearchObjects *searchObject in listContent) {
        if ([scope isEqualToString:@"All"] || [searchObject.type isEqualToString:scope]) {
            [self.filteredListContent addObject:searchObject];
        }
    }
}

- (BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchString:(NSString *)searchString {
    [self filterContentForScope:[[self.searchDisplayController.searchBar scopeButtonTitles] objectAtIndex:[self.searchDisplayController.searchBar selectedScopeButtonIndex]]];    
    // Return YES to cause the search result table view to be reloaded.
    return YES;
}

- (BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchScope:(NSInteger)searchOption {
    [self filterContentForScope:[[self.searchDisplayController.searchBar scopeButtonTitles] objectAtIndex:searchOption]];
    // Return YES to cause the search result table view to be reloaded.
    return YES;
}
@end

Answer 1

You generally don't have to do anything in this case, the data should remain in place. Is there something which is unloading the data? Do you have a viewWillDisappear function which is unloading your array? Are you doing some of the array setup in viewWillAppear.

Put a log statement at the start of your methods to find out when they are being called, it will give you a clearer picture of what's happening.

Answer 2

It is solved. It was a problem which is not obvious with the given source code. There was an error in my logic.