UIActionSheet和UIProgressView的组合

- (void) incrementBar: (id) timer
{
    amountDone += 1.0f;
    [progressView setProgress: (amountDone / 20.0)];
	if (amountDone > 20.0)
	{
		[self.actionSheet dismissWithClickedButtonIndex:0 animated:YES];
		self.actionSheet = nil;
		[timer invalidate];
	}
}

// Load the progress bar onto an actionsheet backing
-(void) action: (UIBarButtonItem *) item
{
	amountDone = 0.0f;
    self.actionSheet = [[[UIActionSheet alloc] initWithTitle:@"Downloading data. Please Wait\n\n\n" delegate:nil cancelButtonTitle:nil destructiveButtonTitle: nil otherButtonTitles: nil] autorelease];
	progressView = [[UIProgressView alloc] initWithFrame:CGRectMake(0.0f, 40.0f, 220.0f, 90.0f)];
    [progressView setProgressViewStyle: UIProgressViewStyleDefault];
    [actionSheet addSubview:progressView];
    [progressView release];
	
	
    // Create the demonstration updates
    [progressView setProgress:(amountDone = 0.0f)];
	[NSTimer scheduledTimerWithTimeInterval: 0.35 target: self selector:@selector(incrementBar:) userInfo: nil repeats: YES];
    [actionSheet showInView:self.view];
	progressView.center = CGPointMake(actionSheet.center.x, progressView.center.y);	
} 

效果如下：