Why am I getting an infinite loop with my UITableView? - iphone

Question

I'm calling a method that selects the first row of the table view when the view loads. But for some reason, after the selectFirstRow is being called, it goes back to self.couldNotLoadData = NO and keeps going back and forth. Any ideas why? When the initial if/else loop goes to else, that method isn't called so it doesn't keep looping.
- (NSInteger)tableView:(UITableView *)aTableView numberOfRowsInSection:(NSInteger)section
{
if (self.ichronoAppointments.count > 0)
{
self.couldNotLoadData = NO;
[self selectFirstRow];
return self.ichronoAppointments.count;
}
else
{
self.couldNotLoadData = YES;
return 1;
}
}
-(void)selectFirstRow
{
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:0 inSection:0];
[self.tableView selectRowAtIndexPath:indexPath animated:YES scrollPosition:UITableViewScrollPositionTop];
}

Answer 1

This is unconfirmed, but I bet that when you call selectRowAtIndexPath:animated:scrollPosition: from selectFirstRow it calls UITableView's delegate's -tableView:numberOfRowsInSection:.
You've got infinite recursion going on, basically. tableView:numberOfRowsInSection calls selectFirstRow which calls selectRowAtIndexPath:animated:scrollPosition: which calls tableView:numberOfRowsInSection ad infinitum.
You need to move your selectFirstRow call to viewDidAppear or viewWillAppear. tableView:numberOfRowsInSection: is no place to be doing anything complex... it's called VERY VERY often.
And while you're at it, move the logic that checks for number of items into selectFirstRow. i.e.
if (self.ichronoAppointments.count) {
//select the first row
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:0 inSection:0];
[self.tableView selectRowAtIndexPath:indexPath animated:YES scrollPosition:UITableViewScrollPositionTop];
} else {
//don't
NSLog(#"Couldn't select first row. Maybe the data is not yet loaded?");
}
It's more DRY/modular/cleaner that way.