How to add a UIActivityView icon on UIToolBar?

How do I add an activity indicator to my toolbar, like the Mail app does when it is checking for email?

If you want to add it through code, not though interface builder, you need to:

1. Create the activity indicator
2. Create UIBarButtonItem that will show the activity indicator
3. Add it into an array of views which will go into your toolbar
4. Put that array in your toolbar

Here's a code sample:

- (void) showActivityIndicator{

    UIActivityIndicatorView *activityView = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhite];
    [activityView startAnimating];
    UIBarButtonItem *item = [[UIBarButtonItem alloc] initWithCustomView:activityView];
    NSArray *items = [[NSArray alloc] initWithObjects:item, nil];
    [self.navigationController.toolbar setItems:items];
    [items release];
    [activityView release]; 
}

Try dragging a UIProgressView onto you UIToolbar in interface builder. Should just work.

In storyboard this is easy. Just drag a view onto the toolbar and then drag on the activity indicator into that.