Okay, so this is what you need to do. In your UICustomObject ( the solid yellow one ) you need to add in another IBOutlet of the type UITabBarController. Once you have done that your code in your UICustomObject should look something like this.
Code:
- (IBAction)buttonWasPressed {
text.textColor = [UIColor redColor];
tabBarController.selectedIndex = 1
The selectedIndex protocol there changes which is the selected item in the tab bar controller. The first item in your tab bar is 0 the second one is 1 (and so on and so forth).
This help?
