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POUITableView cells strangely disappearing
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copied!<p>coming to you from team Marko</p> <p>We are havign an incredible strange problem in which our table view cells, which normally appear like so:</p> <p><img src="https://i.stack.imgur.com/D3Ppr.png" alt="enter image description here"></p> <p>Appear like such:</p> <p><img src="https://i.stack.imgur.com/G0i6q.png" alt="enter image description here"></p> <p>Upon review, the bug seems to happen when you put the iPhone to sleep, then reopen the app and going to the uiviewcontroller in which the tableview is placed. Somehow this makes it so that cellForRowAtIndexPath no longer gets called, even though the delegate and dataources are still set to self. Our sections and row numbers are still normal and we are able to scroll down on the tableview. But since cellForRowAtIndexPath isn't getting called, the tableviewcells are hidden.</p> <p><img src="https://i.stack.imgur.com/s6RMr.png" alt="enter image description here"></p> <p>Here is our tableview setup (I took out stuff from this huge file that has nothing to do with the tableview:</p> <pre><code>// // SPHomeViewController.m // Spek @interface SPHomeViewController () <UITableViewDataSource, UITableViewDelegate, MKMapViewDelegate, SPCreationViewDelegate, UIAlertViewDelegate, CLLocationManagerDelegate> @property (nonatomic, strong) UITableView* tableView; @property (nonatomic, strong) NSMutableArray* tableDatasource; @property (nonatomic, strong) NSMutableArray* datasource; @property (nonatomic, strong) NSMutableArray* friendsDatasource; @property (nonatomic, strong) UISegmentedControl* userFilterSegment; @property (nonatomic) BOOL isLoadingData; @end @implementation SPHomeViewController @synthesize datasource = _datasource; @synthesize friendsDatasource = _friendsDatasource; @synthesize tableDatasource = _tableDatasource; - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil { self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]; if (self) { // Custom initialization } return self; } - (void)viewDidLoad { [super viewDidLoad]; //[[SPLocationManager locationManager] startUpdatingLocationForSig]; [self setNeedsStatusBarAppearanceUpdate]; self.view.backgroundColor = [UIColor colorWithRed:230.0f/255.0f green:230.0f/255.0f blue:230.0f/255.0f alpha:1.0]; self.tableView = [[UITableView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height - kTopBarHeight)]; self.tableView.separatorColor = [UIColor clearColor]; self.tableView.backgroundColor = [UIColor clearColor]; self.tableView.delegate = self; self.tableView.dataSource = self; [self.view addSubview:self.tableView]; } - (void)didReceiveMemoryWarning { [super didReceiveMemoryWarning]; // Dispose of any resources that can be recreated. if (self.creationView.center.y > self.view.frame.size.height) { self.creationView = nil; } NSLog(@"Mem warning"); } //**************************************** //**************************************** #pragma mark - UITableViewDelegate/DataSource //**************************************** //**************************************** - (UITableViewCell*)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { NSLog(@"INDEX PATH ROW: %d AND SECTION: %d", indexPath.row, indexPath.section); if (indexPath.section == 0) { UITableViewCell* cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"SPMapCellSpace"]; cell.backgroundColor = [UIColor clearColor]; cell.backgroundView = [[UIView alloc] init]; cell.selectedBackgroundView = [[UIView alloc] init]; return cell; } else if (indexPath.section == self.tableDatasource.count + 1) { UITableViewCell* cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"SPBottomCellSpace"]; cell.backgroundColor = [UIColor clearColor]; cell.backgroundView = [[UIView alloc] init]; cell.selectedBackgroundView = [[UIView alloc] init]; return cell; } SPMark* mark = self.tableDatasource[indexPath.section - 1]; NSString* reuseId = [SPHomeViewController cellIdentifierFromData:mark]; SPTableViewCell* cell = [tableView dequeueReusableCellWithIdentifier:reuseId]; if (cell == nil) { cell = [SPTableViewCell cellFromMark:mark reuseID:reuseId]; [cell updateView:YES]; } [cell addDataToCell:mark]; if (indexPath.section >= self.tableDatasource.count - 2 && !self.isLoadingData && self.pageNumber != -1) { self.fetchNextPage = YES; // When the scrollview stops it will load more data if available. } return cell; } - (unsigned int)getPageNumber { return (self.userFilterSegment.selectedSegmentIndex == 0) ? self.pageNumber : self.friendsPageNumber; } - (void)setCurrentPageNumber:(unsigned int)page { if (self.userFilterSegment.selectedSegmentIndex == 0) { self.pageNumber = page; } else { self.friendsPageNumber = page; } } - (void)incrementCurrentPageNumber { if (self.userFilterSegment.selectedSegmentIndex == 0) { self.pageNumber++; } else { self.friendsPageNumber++; } } // Every cell has a section header so this should be equal to the number of speks returned from the server - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { NSLog(@"section count is: %d",self.tableDatasource.count + 2 ); return self.tableDatasource.count + 2; // Add two because the mapview needs to go on the top and extra spacing at the bottom. } // There is a section for every cell, so there is only one cell per section - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { return 1; } - (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath { if (indexPath.section == 0) { return kMapHeight+2; } else if (indexPath.section == self.tableDatasource.count + 1) { return kExtraSpaceBelowHomeView; } SPMark* mark = self.tableDatasource[indexPath.section - 1]; return [SPTableViewCell cellHeightForMark:mark]; } - (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath { if (indexPath.section == 0 || indexPath.section == self.tableDatasource.count + 1) { cell.backgroundColor = [UIColor clearColor]; } } - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { if (indexPath.section == 0 || indexPath.section == self.tableDatasource.count + 1) return; SPMark* mark = self.datasource[indexPath.section - 1 ]; SPMarkViewController* markVC = [SPMarkViewController withMark:mark]; [markVC displayData]; [self.navigationController pushViewController:markVC animated:YES]; } -(void)reloadTableview { [self.tableView setDelegate:self]; dispatch_async(dispatch_get_main_queue(), ^{ [self.tableView reloadData]; [self.tableView setNeedsDisplay]; }); } - (void)showNoItems { if (self.tableDatasource.count == 0 && self.accuracyBad == NO) { self.opaqueIcon.hidden = NO; self.noItems.hidden = NO; self.beTheFirst.hidden = NO; self.downArrow.hidden = NO; self.noItemsBackround.hidden = NO; [self.view bringSubviewToFront:self.noItemsBackround]; [self.view bringSubviewToFront:self.downArrow]; [self.view bringSubviewToFront:self.beTheFirst]; [self.view bringSubviewToFront:self.noItems]; [self.view bringSubviewToFront:self.opaqueIcon]; } } - (void)showTableView { if (self.tableDatasource.count != 0) { self.noItems.hidden = YES; self.beTheFirst.hidden = YES; self.downArrow.hidden = YES; self.noItemsBackround.hidden = YES; self.opaqueIcon.hidden = YES; [self.view sendSubviewToBack:self.noItemsBackround]; [self.view sendSubviewToBack:self.downArrow]; [self.view sendSubviewToBack:self.beTheFirst]; [self.view sendSubviewToBack:self.noItems]; [self.view sendSubviewToBack:self.opaqueIcon]; } } //**************************************** //**************************************** #pragma mark - Setters/Getters //**************************************** //**************************************** - (NSMutableArray*)datasource { if (!_datasource) { _datasource = [NSMutableArray array]; if (!self.firstLoad) { [self loadDataForPagination:NO]; } } return _datasource; } - (NSMutableArray*)friendsDatasource { if (!_friendsDatasource) { _friendsDatasource = [NSMutableArray array]; if (!self.firstLoad) { [self loadDataForPagination:NO]; } } return _friendsDatasource; } - (NSMutableArray*)tableDatasource { if (!_tableDatasource) { _tableDatasource = (self.userFilterSegment.selectedSegmentIndex == 0) ? self.datasource : self.friendsDatasource; } return _tableDatasource; } - (SPCreationView*)creationView { if (!_creationView) { UIView* window = [SPUtils getAppDelegate].window; CGSize viewSize = window.frame.size; CGRect startFrame = CGRectMake(0, viewSize.height, [SPUtils screenWidth], [SPUtils screenHeight]); _creationView = [SPCreationView creationView:startFrame delegate:self]; [window insertSubview:_creationView belowSubview:self.creationButton]; _creationView.frame = startFrame; } return _creationView; } - (void)setTableDatasource:(NSMutableArray *)tableDatasource { _tableDatasource = tableDatasource; [self preFetchImages]; dispatch_async(dispatch_get_main_queue(), ^{ if(_tableDatasource == nil || _tableDatasource.count == 0) { [self showNoItems]; } else { [self showTableView]; } [self reloadTableview]; }); } - (void)setDatasource:(NSMutableArray *)datasource { _datasource = datasource; } - (void)setFriendsDatasource:(NSMutableArray *)friendsDatasource { _friendsDatasource = friendsDatasource; } @end </code></pre> <p>Lastly, if you think it has something to do with our delegate, we don't touch the view controller there, so I don't see how that could be a problem. Maybe a memory issue or a background thread issue?</p>

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