Iphone - UIView not displayed - iphone

Question

I have a strange problem with a UIView :
I want to show an Activity Indicator View that I created with Interface Builder to indicate long running activity.
In the viewDidLoad function of my principal viewController I init the ActivityIndicator View like this :
- (void)viewDidLoad {
[super viewDidLoad];
appDelegate = (MyAppDelegate *)[[UIApplication sharedApplication] delegate];
load = [[ActivityIndicatorViewController alloc] init];
...
When I push a button it call this IBAction :
- (IBAction)LaunchButtonPressed{
// Show the Activity indicator view.
[self.view addSubview:load.view];
// eavy work
[self StartWorking];
// Hide the loading view.
[load.view removeFromSuperview];
}
In the StartWorking function, I ask a request to an internet serveur and parse the XML file that it return me.
The problem is that if I Call my StartWorking function, the application do not start by showing the Activity Indicator view but with the StartWorking function.
Whereas if I remove the call to StartWorking function, the view is shown.
Is someone able to explain me why? :s

Answer 1

Have you tried to call the StartWorking method on a different thread?
Maybe its heavy process prevents other instructions to take place.
Look at the NSThread class, especially the detachNewThreadSelector:toTarget:withObject: method.
EDIT: About the pool problem, you need to create a pool in your StartWorking method, if it's called on a different thread:
- ( void )StartWorking
{
NSAutoreleasePool * pool = [ [ NSAutoreleasePool alloc ] init ];
/* Code here... */
[ pool release ];
}

Answer 2

Replace :
[self.view addSubview:load.view];
With :
[self performSelector:#selector(addLoadingSubview) afterDelay:0.1f];
And create the method :
-(void)addLoadingSubview{[self.view addSubview:load.view];}

Answer 3

Ok, I found a solution based on santoni answer :
- (IBAction)LaunchButtonPressed{
// Show the Activity indicator view.
[self performSelector:#selector(ShowActivityIndicatorView) withObject:nil afterDelay:0];
// eavy work
[self performSelector:#selector(StartWorking) withObject:nil afterDelay:2];
// Hide the loading view.
[load.view removeFromSuperview];
}
The Activity Indicator view is dislayed before the call to the eavy function.
Thank's for answering.