iOS UINavigationBar vs UIToolbar vs UITabBar

Question

Let me know which one should be used in what case.

What are differences among them?

What are the advantage and disadvantage of each component?

Answer 1

To quote big brother:

Tabbar

If your application provides different perspectives on the same set of data, or different subtasks related to the overall function of the application, you might want to use a tab bar. A tab bar appears at the bottom edge of the screen.

A tab bar gives users the ability to switch among different modes or views in an application, and users should be able to access these modes from everywhere in the application

Toolbar

If your application provides a number of actions users can take in the current context, it might be appropriate to provide a toolbar

However that doesn't give you a completely clear application-based decision. The best solution is to look at the iPhone inbuilt applications (Clock and iPod) along with Appstore-approved apps and stick to what is consistent, as that is what the Apple HIG guides and the appstore approval process boils down to.