ios - Aligning UIToolBar items

Question

I have three UIBarButtonItem created as below. They align left and I'd like to align center so there isn't a gap on the right side. I don't see an align property on UIToolBar. Is there another way to accomplish this?

//create some buttons
UIBarButtonItem *aboutButton = [[UIBarButtonItem alloc] initWithTitle:@"About" style:UIBarButtonItemStyleBordered target:self action:@selector(showAbout:)];
[toolbar setItems:[NSArray arrayWithObjects:settingsButton,deleteButton,aboutButton,nil]];
//Add the toolbar as a subview to the navigation controller.
[self.navigationController.view addSubview:toolbar];

Answer 1

Add two UIBarButtonSystemItemFlexibleSpace items to your toolbar, to the left and right of your items

UIBarButtonItem *flexibleSpace = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil];
[toolbar setItems:[NSArray arrayWithObjects:flexibleSpace, settingsButton,deleteButton,aboutButton, flexibleSpace, nil]];

Adding these as you would any other toolbar items will distribute space evenly between the two of them.