Activity Indicator doesn't spin - objective-c

Question

I'm trying to add a spinning activity indicator (UIActivityIndicatorView) to my app while it parses data from the internet. I have an IBOutlet (spinner) connected to a UIActivityIndicatorView in IB. Initially I had it set up like this:
-
(void) function {
self.spinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle: UIActivityIndicatorViewStyleWhite];
self.spinner.hidesWhenStopped = YES;
[spinner startAnimating];
//parse data from internet
[spinner stopAnimating];}
But the spinner wouldn't spin. I read that it had something to do with everything being on the same thread. So I tried this:
- (void) newFunction {
self.spinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle: UIActivityIndicatorViewStyleWhite];
self.spinner.hidesWhenStopped = YES;
[spinner startAnimating];
[NSThread detachNewThreadSelector: #selector(function) toTarget: self withObject: nil];
[spinner stopAnimating];}
But still no luck. Any ideas? Thanks.

Answer 1

Your newFunction: method should look like this:
- (void) newFunction {
self.spinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhite];
self.spinner.hidesWhenStopped = YES;
[NSThread detachNewThreadSelector: #selector(function) toTarget: self withObject: nil];
}
And your function method should look like this:
- (void) function {
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
[self.spinner performSelectorOnMainThread:#selector(startAnimating) withObject:nil waitUntilDone:NO];
//...
[self.spinner performSelectorOnMainThread:#selector(stopAnimating) withObject:nil waitUntilDone:NO];
[pool drain];
}

Answer 2

you should not intitialize indicator again .please replace your code with this.
-(void) function {
[spinner startAnimating];
[self performSelector:#selector(newfunction) withObject:nil afterDelay:3.0];
}
- (void) newfunction {
[spinner stopAnimating];
}
Thanks.

Answer 3

Just see that the "//parse data from internet " is synchronous or asynchronous. Asynchronous would mean that a separate thread would start from that point on, and the current function execution will continue without delay.
In your second example, you are explicitly making separate thread, which means that #selector(function) will happen on a separate thread, and the next statement [spinner stopAnimating] is executed immediately. So, it seems like spinner is not spinning at all.
Moreover, make sure you start and stop the activity indicator on main thread only.