UITableViewCell Doesn't display loaded data but displays it when selected - ios

Question

I am facing a weird issue and I am sure I am doing something wrong. In my UITableViewController class I have a function as follows:
-(void)EERefreshView
{
NSLog(#"App delegate requested the view be refreshed");
[self loadEventsFromDB];
for(int a=0;a<eventsList.count;a++)
{
DB_EEEvent *event = (DB_EEEvent*)eventsList[a];
UITableViewCell *cell =
[self.tableView dequeueReusableCellWithIdentifier:#"Cell"];
//NSLog(#"CellID %#", cell.reuseIdentifier);
//get references to the UI components
UILabel *lblTitle = (UILabel*)[cell.contentView viewWithTag:5];
UILabel *lblDate = (UILabel*) [cell.contentView viewWithTag:6];
UIImageView *imgEvent = (UIImageView*)[cell.contentView viewWithTag:7];
//set values
lblTitle.text = event.name;
lblDate.text = [NSString stringWithFormat:#"%# - %#",
event.startdate,event.enddate];
AppDelegate *del = [AppDelegate sharedAppDelegate]; //need this to get the BaseURL
// Here we use the new provided setImageWithURL: method to load the web image
NSString * imageURL =[[NSString alloc] initWithFormat:#"http://%#%#",del.api.BaseURL,event.logo];
NSString* webStringURL = [imageURL stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSURL *url = [NSURL URLWithString:webStringURL];
[imgEvent setImageWithURL:url placeholderImage:[UIImage imageNamed:#"placeholder.png"] completed:^(UIImage *image, NSError *error, SDImageCacheType cacheType) {
//do somethign when image call completes
}];
[eventsListCells addObject:cell];
if(a == selectedEvent)
{
}
}
dispatch_async(dispatch_get_main_queue(), ^{
[tblEventsList reloadData];
});
}
This function loads an array with UITableViewCell objects which is then used later on by
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
// Configure the cell data
NSLog(#"IndexPathRow: %d", indexPath.row);
UITableViewCell *cell = (UITableViewCell*)eventsListCells[indexPath.row];
return cell;
}
However when the cell is loaded lblTitle and lblDate have no text displaying in them. But when I tap on a cell it then displays the text in the labels. So this means that the data is there but its not being refresh when initially created. I suspect this might have something to do with threads but I am not an expert on the subject and would appreciate any help that I can get.

Answer 1

I see what is bothering you and why you created this method, but you don't need it. The only reason why you need back thread is your image loading so that should be thrown in bkg. thread and the rest of the code should be in -
(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath.
U really don't need to pre create cells, and U cant cause they are reusable. For example if you have 50 elements in eventsList and room for only 5 cell on your screen you cant create 50 cells cause the code will create only 5+1 and reuse them as they appear on the screen, so every element of your eventsList will use one of those 5 cells and on the other side every cell will be a host for 10 different elements from your eventsList array. So as you can see your code doesn't make much sense...

Answer 2

The second function you mentioned in your question is the function that is called to populate the table with data. When you call [tblEventsList reloadData]; your app just calls the (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath method. So this method needs to be outputting data back to the table. A very simple example is below. Also, make sure your table delegate and data source are set.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView
dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc]
initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:CellIdentifier];
}
// Configure the cell.
cell.textLabel.text = [self.your_data_source objectAtIndex:[indexPath row]];
return cell;
}