dispatch_async Reload UITableView not working - ios

Question

Sorry I'm noobs on Cocoa, since I'm new on iOS mobile development.. straight to the point, I've use GCD method on Cocoa to assign data to tableview but when I fire [tableview reloadData] it's not working. Here my sample code:
-(void)updateCell{
dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
dispatch_async(queue, ^{
NSIndexPath* indexPath;
// Insert code to be executed on another thread here
if(clean_data){
for (int i=0; i<clean_data.count; i++) {
indexPath= [NSIndexPath indexPathForRow:i inSection:0];
sqCell *cell = (sqCell *)[stockQ cellForRowAtIndexPath:indexPath];
for (int j=0; j<plist.count; j++) {
NSString *a =[[clean_data objectAtIndex:i]objectAtIndex:1];
NSString *b =[[[plist objectAtIndex:j]objectForKey:#"data"]objectAtIndex:0];
if([a isEqualToString:b]){
cell.last.text =[[clean_data objectAtIndex:i]objectAtIndex:1];
cell.change.text = #"1231231312312";
}
}
}
}
dispatch_async(dispatch_get_main_queue(), ^{
// Insert code to be executed on the main thread here
///reload table here
[self reload];
});
});
}
here method to reload data
-(void)reload{
NSLog(#"reload");
[stockQ setNeedsLayout];
[stockQ setNeedsDisplay];
[stockQ reloadData];
}
the console show "reload" text, but not firing stockQ UITableCiew.. what happen in my code?

Answer 1

You don't do UI handling code in an async thread. Modifying the UI (like updating the tableView) - should always be done in the main thread. Try to pull that code from an async task and see if it works or not.
Another remark - why in any way do you need to reload the data in an async task? Table view is very lightweight & fast. All your code from the post should be ran within milliseconds. Use dispatch_async only for long running, time consuming tasks!