IOS Human Interface Guidelines (original translation) Chapter II

Anatomy of the IOS app

Almost all iOS apps use at least some UI components defined by the Uikit framework. When you design your app's UI, you know that the names, roles, and functions of these basic components can help you make well-reasoned decisions.

The UI elements provided by Uikit are divided into four categories:

Bar Bars include information about the environment that tells users where they are located (positioning), and controls that help users navigate or make actions.

• Content view. The content view contains app-specific content and allows you to swipe, insert, delete, and rearrange the elements to manage these behaviors.

Control The control behaves or exhibits information.

• Temporary view. The temporary view can be briefly displayed to provide users with important information and features or additional options.

In addition to defining UI elements, Uikit also defines objects that enable functionality, such as gesture recognition, drawing, authorization access, and support for printing.

From a programmatic point of view, a UI element is actually one of the views because it inherits from the UIView. A view knows how to portray itself on the screen, and it can know when the user clicks within its bounds. Controls (such as buttons and sliders), content views (such as collection views and table views), and temporary views (such as warning windows and action sheets (not knowing why translations are appropriate) are view types.

In order to manage some of the column views or view systems in your app, you need to use a view controller in particular. The controller is able to display different views through coordinates, implement the functions behind user interaction, and manage transitions from one screen to another. For example, set up a system that uses a navigation controller to represent the view.

Here's an example of how a view and view controller can be combined to render a UI in an iOS app. (The picture is not posted)

Although developers think in terms of views and view controllers, users tend to experience the iOS app as a collection of screens. From this point of view, a screen is roughly the same as a unique visual state or pattern in the app.

Note: A iosapp includes a window---but it's not like a window in a computer app---an iOS window doesn't have a visual part and it can't be moved to another location on the screen. Most iOS apps contain only one window, and an app that supports an external screen may have more than one window.

In the iOS human interaction guidelines, the word screen is meant as most users understand. As a developer, you may also read the word in other contexts. In those environments, you can use this object to access an external screen, which is designed to UIScreen.

IOS Human Interface Guidelines (original translation) Chapter II