TableViewCell subtitle won't change unless the cell is tapped - ios

Question

The cells in my table have a subtitle set that will show some extra information loaded from a web server. When the app loads the subtitle will just say "Loading..." and then when the response is received, and parsed the cell is updated.
The problem is, unless I tap on the cell the subtitle will stay at "Loading...". As soon as I tap on it it updates to the correct subtitle.
Here I initialize the cell, and set the temporary subtitle while the http request is performed
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
// Setting the tableviewcell titles
UITableViewCell * cell = [tableView dequeueReusableCellWithIdentifier:#"Cell" forIndexPath:indexPath];
cell.detailTextLabel.text = #"Loading...";
cell.detailTextLabel.enabled = NO;
return cell;
}
I've tried making calling the request method in different places:
willDisplayCell and in cellForRowAtIndexPath.
The method that gets the data from the web server uses an asynchronous NSURLConnection which when a successful response is received I update the cell subtitle text using:
// Map Reduce the array used by the TableView
for (int i = 0; i < [self.routes count]; i++) {
if(cellMatches){
UITableViewCell *cell = [self.tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:i inSection:0]];
cell.detailTextLabel.text = #"Data received!";
cell.userInteractionEnabled = YES;
cell.textLabel.enabled = YES;
cell.detailTextLabel.enabled = YES;
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
}
I know that you can reload a specific cell using tableView reloadRowsAtIndexPaths but that doesn't seem to work when I implement this code:
[self.tableView beginUpdates];
// Change cell subtitle
[self.tableView reloadRowsAtIndexPaths:#[indexPath] withRowAnimation:UITableViewRowAnimationNone];
[self.tableView endUpdates];
I have a timer set up to call the request method every 30 seconds, when that is called it works no problem and updates the subtitle right away without me having to tap it. So I think the problem is that the cell isn't initialized or maybe it's being reinitialized after the web request is made. But I don't call reloadAllData during this method.

Answer 1

What you need to do is update your cellForRowAtIndexPath so it checks for the data. If the data is available, set the subtitle to the data, otherwise show "Loading". This requires that you have some sort of data model that stores the data when it is received.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
UITableViewCell * cell = [tableView dequeueReusableCellWithIdentifier:#"Cell" forIndexPath:indexPath];
BOOL enabled = YES;
NSString *subtitle = ... // get the value from the data model
if (subtitle) {
cell.textLabel.text = ... // whatever value goes here
cell.detailTextLabel.text = subtitle;
cell.detailTextLabel.enabled = YES;
} else {
// There's no value for this row yet - show "Loading"
cell.textLabel.text = ... // whatever value goes here when loading
cell.detailTextLabel.text = #"Loading";
cell.detailTextLabel.enabled = NO;
}
return cell;
}
Be sure you set the same set of cell properties in both halves of the if/else statement as needed.
When you get new data and update your data model, simply call reloadRowsAtIndexPaths: for the proper cell path. The above code will then properly update the cell.
The code you have now to update a cell should be removed since it is not the proper way.

Answer 2

Try this:
[self.tableView reloadSections:[NSIndexSet indexSetWithIndex:0] withRowAnimation:UITableViewRowAnimationAutomatic];
Instead of:
[self.tableView reloadRowsAtIndexPaths:#[indexPath] withRowAnimation:UITableViewRowAnimationNone];

Answer 3

Alongside with rmaddy's solution, I also needed to add one important thing that I found in a similar question:
dispatch_async(dispatch_get_main_queue(), ^{
[self.tableView reloadData];
});
Fixed the issue completely.