A navigation bar appears at the top of an app screen, and enables navigation through a series of hierarchical app screens. When a new screen is displayed, a back button, preceded by a chevron and often labeled with the title of the previous screen, appears on the left side of the bar. Sometimes, the right side of a navigation bar contains a control, such as a Search button, for interacting with the active view.
Consider showing the title of the current view in the navigation bar. In most cases, a title provides context by letting people know what they’re looking at. However, if titling a navigation bar seems redundant, you can leave the title empty. For example, the Now Playing screen in the Music app doesn’t include a title in the navigation bar because the rest of the screen provides sufficient context.
Avoid crowding a navigation bar with too many controls. In general, a navigation bar should contain no more than the view’s current title, a back button, and one or two controls for interacting with the view’s contents.
Don’t include multisegment breadcrumb paths. The back button always performs a single action—returning to the previous screen. If you think people might get lost without the full path to the current screen, consider flattening your app’s hierarchy.
Give text-titled buttons enough room. If your navigation bar includes multiple text buttons, the text of those buttons may appear to run together, making the buttons indistinguishable. Add separation by inserting a fixed space item between the buttons. For developer guidance, see the UIBarButtonSystemItemFixedSpace constant value in UIBarButtonItem.
Use the standard back button. People know that the standard back button lets them retrace steps through a hierarchy of information.
For developer guidance, see UINavigationBar.