Adding a persistent UIView with a UITabBarController

Question

I have an app using a UITabBarController, and I have another view that needs to slide up from behind the tab bar controls, but in front of the tab bar's content. If that's not clear, imagine an advertisement sliding up in a tabbed app that appears in front of everything except for the tab bar buttons.

So far I have code that looks something like this, but I'm willing to change it if there's a better way to do this...

tabBarController.viewControllers = [NSArray arrayWithObjects:locationNavController, emergencyNavController, finderNavController, newsNavController, nil]; 

aboutView = [[AboutView alloc] initWithFrame:CGRectMake(0, window.frame.size.height - tabBarController.tabBar.frame.size.height - 37 ,
                                                        320, window.frame.size.height - tabBarController.tabBar.frame.size.height)];


[window addSubview:tabBarController.view];    // adds the tab bar's view property to the window
[window addSubview:aboutView]; // this is the view that slides in
[window makeKeyAndVisible];

Currently aboutView is a subclass of UIView and sits at its starting position at the bottom, but it hides the tabBarController. How can I change this to let the tabs be on top, but still have the aboutView in front of the other content?

Answer 1

You need to add the aboutView as a subview of the view in the currently active view controller in the UITableBarController. You can access that view via the selectedViewController property.

You can add code to your aboutView implementation to animate the view when it appears.

I do something like this in a popup view that I want to appear under the tab bar controls. You can add some code to the didMoveToSuperview message on the aboutView implementation:

- (void)didMoveToSuperview
{
    CGRect currentFrame = self.frame;

    // animate the frame ... this just moves the view up a 10 pixels. You will want to
    // slide the view all the way to the top
    CGRect targetFrame = CGRectOffset(currentFrame, 0, -10);

    // start the animation block and set the offset
    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:0.5]; // animation duration in seconds
    [UIView setAnimationDelegate:self];

    self.frame = targetFrame;

    [UIView commitAnimations];  
}

So when your aboutView is added to the selected view controller's view, it automatically animates up.