How are toolbars hidden using animation

What is the built in method which can be used to hide and show t开发者_开发百科oolsbars. specifying a rate or speed of the animation?

Look at this question, and do something like:

[UIView animateWithDuration:2.0
            animations:^{ 
                [self.navigationController setToolbarHidden:YES animated:YES];
            } 
            completion:^(BOOL finished){
                        // whatever
            }];

Toolbar's just a view—add an IBOutlet in your controller, then use UIView's (class methods) block animation methods, such as animateWithDuration:delay:options:animations:completion: or animateWithDuration:animations:. In the animation block, just move the view.frame.size.origin.y to a different location, or set its opacity to zero. the methods also allow you to specify the time period over which the animation will occur. Once complete (there's a delegate callback in the first method), you can then ask your main view to get taller by using the same methods to change the view.frame.size.origin.y of your main view.