Question

I want to show the activity indicator on tap gesture and also navigate from current viewcontroller to next viewcontroller I have written code on tap gesture method my code is –

- (void)tapToAutoFocus:(UIGestureRecognizer *)gestureRecognizer
{
    textLabel.hidden = YES;
    indicator  = [[UIActivityIndicatorView alloc] initWithFrame:CGRectMake(140, 150, 30, 30)];
    [indicator setActivityIndicatorViewStyle:UIActivityIndicatorViewStyleWhiteLarge];
    [self.view addSubview:indicator];
    [indicator startAnimating];

    AccountAnfordernViewController *accountAnfordernViewController = [[AccountAnfordernViewController alloc]init];
    [self.navigationController pushViewController:accountAnfordernViewController animated:YES];
    [accountAnfordernViewController release];
}

It navigates to next view controller but indicator are not showing, I want when it navigate to nextviewcontroller at that time indicator also should be show for some time and then navigate to next view controller. What should I do for that?

Answer 1

I suspect you need to do something like this:

- (void)tapToAutoFocus:(UIGestureRecognizer *)gestureRecognizer
{
    textLabel.hidden = YES;
    indicator  = [[UIActivityIndicatorView alloc] initWithFrame:CGRectMake(140, 150, 30, 30)];
    [indicator setActivityIndicatorViewStyle:UIActivityIndicatorViewStyleWhiteLarge];
    [self.view addSubview:indicator];
    [indicator startAnimating];
    [self performSelector:@selector(pushAccountAnfordern) withObject:nil afterDelay: 0.1];
}

- (void) pushAccountAnfordern;
{
    AccountAnfordernViewController *accountAnfordernViewController = [[AccountAnfordernViewController alloc]init];
    [self.navigationController pushViewController:accountAnfordernViewController animated:YES];
    [accountAnfordernViewController release];
}

You can vary the delay. And, indeed, 0.0 may be just fine. This way of doing it lets the current run loop end, giving a chance for the spinner to start showing before starting the next bit of code. For a different approach (with potential side effects) to forcing the spinner to start before the current run loop ends this this SO question.