What is a navigation controller?

In iOS development, a navigation controller is a specialized view controller provided by UIKit that manages a stack of view controllers in a hierarchical navigation structure. It facilitates the presentation and navigation between different content views in an iOS app, typically using a navigation bar at the top of the screen for navigation controls.

Key features of a navigation controller include:

• Navigation Stack: The navigation controller maintains a stack of view controllers, where each view controller represents a distinct content view in the navigation hierarchy. View controllers can be pushed onto the stack to navigate forward or popped off the stack to navigate backward.
• Navigation Bar: The navigation controller displays a navigation bar at the top of the screen, which typically contains a title, back button, and optional additional buttons for navigation actions. The navigation bar provides a consistent navigation interface across different views within the navigation stack.
• Navigation Controller Hierarchy: Navigation controllers can be nested within other container view controllers, allowing for complex navigation structures and workflows. Parent-child relationships between navigation controllers enable the composition of sophisticated navigation interfaces.
• Navigation Transitions: The navigation controller manages transitions between view controllers in the navigation stack, including push, pop, present, and dismiss transitions. It provides built-in support for animated navigation transitions and customizable navigation behavior.
• Navigation Controller Delegate: The navigation controller delegate protocol allows developers to customize navigation behavior and respond to navigation-related events. By adopting the UINavigationControllerDelegate protocol, developers can intercept navigation actions and customize navigation transitions, appearance, and behavior.

Navigation controllers are commonly used in iOS apps to implement hierarchical navigation patterns, such as drill-down navigation, master-detail interfaces, and tab-based navigation. They provide a convenient and standardized way to manage navigation flows and simplify the implementation of complex navigation interfaces in iOS applications.