UIButton

UIButton is a UIControl subclass in UIKit that presents a tappable button interface for user interaction. It is commonly used to trigger actions through the target-action mechanism and can be customized in appearance, behavior, and state.

A UIButton can represent several types, such as System, Custom, Detail Disclosure, and Close, which influence default styling and behavior. It supports multiple control states, including normal, highlighted, disabled, selected, and, on tvOS, focused. The control reacts to touch events and can deliver actions to a target via methods like addTarget(_:action:for:), typically responding to the touchUpInside event.

Appearance and content are flexible. A button can display text, an image, or both. Its title, image, and their colors can be set for different states using methods such as setTitle(_:for:), setImage(_:for:), and setTitleColor(_:for:). You can also adjust layout with titleEdgeInsets, imageEdgeInsets, and contentEdgeInsets, or use a background image. UIButton supports attributed titles and, in recent iOS versions, a configuration-based styling API that offers a modern approach to appearance while preserving legacy properties for compatibility.

Buttons are produced either programmatically or in Interface Builder. Programmatically, you can instantiate with UIButton(type:), or via init and then configure. In Interface Builder, a UI button is placed on the canvas and its connections, title, and images are set in the Attributes Inspector.

Accessibility considerations include exposing a meaningful accessibilityLabel and ensuring a clear action is conveyed to assistive technologies. UIButton is a foundational element for user interaction in iOS and related platforms.