Display a UIAlertView if no new posts were found - objective-c

Question

I am developing an app for my website that has an RSS Feed with a parser. I made a refresh button to look for new posts and it works. But now, I want it to display a UIAlertView that says "No posts found" if there were no new posts found.
This is my refresh button
- (IBAction)refreshButton:(UIBarButtonItem *)sender
{
// Create a new data container for the stuff that comes back from the service
xmlData = [[NSMutableData alloc] init];
// Construct a URL that will ask the service for what you want -
// Note we can concatenate literal strings together on multiple lines in this way it
// results in a single NSString instance
NSURL *url = [NSURL URLWithString:
#"http://sephardijews.com/feed/"];
// Putting the URL we made into an NSURLRequest, so we can connect to the url data that we specifed
NSURLRequest *req = [NSURLRequest requestWithURL:url];
// Creating a connecting that will exchange this request for the data from the URL we specifed
connection = [[NSURLConnection alloc] initWithRequest:req
delegate:self
startImmediately:YES];
[[self tableView] reloadData];
NSLog(#"%#\n %#\n %#\n", channel, [channel title], [channel infoString]);
}
How could I do this? Something with an if statement right?
The refresh button:
- (IBAction)refreshButton:(UIBarButtonItem *)sender
{
// Create a new data container for the stuff that comes back from the service
xmlData = [[NSMutableData alloc] init];
// Construct a URL that will ask the service for what you want -
// Note we can concatenate literal strings together on multiple lines in this way it
// results in a single NSString instance
NSURL *url = [NSURL URLWithString:
#"http://sephardijews.com/feed/"];
// Putting the URL we made into an NSURLRequest, so we can connect to the url data that we specifed
NSURLRequest *req = [NSURLRequest requestWithURL:url];
// Creating a connecting that will exchange this request for the data from the URL we specifed
connection = [[NSURLConnection alloc] initWithRequest:req
delegate:self
startImmediately:YES];
[[self tableView] reloadData];
NSLog(#"%#\n %#\n %#\n", channel, [channel title], [channel infoString]);
if ([[self tableView] numberOfRowsInSection:0] > someNumberVariableForLastCount) {
someNumberVariableForLastCount = [[self tableView] numberOfRowsInSection:0];
[[self tableView] reloadData];
}else{
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"No New Posts" message:#"There were no new posts found" delegate:self cancelButtonTitle:#"Dismiss" otherButtonTitles:nil, nil];
[alert show];
}
}

Answer 1

Your reloadData call should occur in connectionDidFinishLoading, not right after you start the connection (it is an asynchronous network call, the table will be reloaded before anything is even fetched). The alert should be kicked off there too. You need to implement all the connection delegate stuff, hopefully you've done that. If not, basic example here.

Answer 2

This will compare the current row count in a section you specify to a variable for the last count:
if ([[self tableView] numberOfRowsInSection:0] > someNumberVariableForLastCount) {
someNumberVariableForLastCount = [[self tableView] numberOfRowsInSection:0];
[[self tableView] reloadData];
}else{
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"no new items" message:#"OH NO!!" delegate:self cancelButtonTitle:#"Dismiss" otherButtonTitles:nil, nil];
[alert show];
}