-(void)showActivityViewer
{
	self.activityView = [[[UIView alloc] initWithFrame: CGRectMake(0, 0, self.view.window.bounds.size.width, self.view.window.bounds.size.height)] autorelease];
	activityView.backgroundColor = [UIColor blackColor];
	activityView.alpha = 0.5;

	self.activityWheel = [[[UIActivityIndicatorView alloc] initWithFrame: CGRectMake(self.view.window.bounds.size.width / 2 - 12, self.view.window.bounds.size.height / 2 - 12, 24, 24)] autorelease];
	activityWheel.activityIndicatorViewStyle = UIActivityIndicatorViewStyleWhiteLarge;
	activityWheel.autoresizingMask = (UIViewAutoresizingFlexibleLeftMargin |
									  UIViewAutoresizingFlexibleRightMargin |
									  UIViewAutoresizingFlexibleTopMargin |
									  UIViewAutoresizingFlexibleBottomMargin);
	[activityView addSubview:activityWheel];
	[self.view.window addSubview: activityView];
	[[[activityView subviews] objectAtIndex:0] startAnimating];
}

-(void)removeActivityViewer {
	[activityWheel removeFromSuperview];
	[activityView removeFromSuperview];
	self.activityWheel = nil;
	self.activityView = nil;
}