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UIKit Constants Reference

This document describes constants that are used throughout the UIKit framework.

Constants

  • Defines a set of edge insets where all of the values are 0.

    Declaration

    Swift

    let UIEdgeInsetsZero: UIEdgeInsets

    Objective-C

    extern const UIEdgeInsets UIEdgeInsetsZero;

    Constants

    • UIEdgeInsetsZero

      UIEdgeInsetsZero

      A UIEdgeInsets struct whose top, left, bottom, and right fields are all set to the value 0.

      Available in iOS 2.0 and later.

  • Defines an offset where all of the values are 0.

    Declaration

    Swift

    let UIOffsetZero: UIOffset

    Objective-C

    extern const UIOffset UIOffsetZero;

    Constants

    • UIOffsetZero

      UIOffsetZero

      A UIOffset struct whose horizontal and vertical fields are set to the value 0.

      Available in iOS 5.0 and later.

  • Constants that specify the edges of a rectangle.

    Declaration

    Swift

    struct UIRectEdge : RawOptionSetType { init(_ rawValue: UInt) init(rawValue rawValue: UInt) static var None: UIRectEdge { get } static var Top: UIRectEdge { get } static var Left: UIRectEdge { get } static var Bottom: UIRectEdge { get } static var Right: UIRectEdge { get } static var All: UIRectEdge { get } }

    Objective-C

    typedef enum : NSUInteger { UIRectEdgeNone = 0, UIRectEdgeTop = 1 << 0, UIRectEdgeLeft = 1 << 1, UIRectEdgeBottom = 1 << 2, UIRectEdgeRight = 1 << 3, UIRectEdgeAll = UIRectEdgeTop | UIRectEdgeLeft | UIRectEdgeBottom | UIRectEdgeRight } UIRectEdge;

    Constants

    • None

      UIRectEdgeNone

      No edge.

      Available in iOS 7.0 and later.

    • Top

      UIRectEdgeTop

      The top edge of the rectangle.

      Available in iOS 7.0 and later.

    • Left

      UIRectEdgeLeft

      The left edge of the rectangle.

      Available in iOS 7.0 and later.

    • Bottom

      UIRectEdgeBottom

      The bottom edge of the rectangle.

      Available in iOS 7.0 and later.

    • Right

      UIRectEdgeRight

      The right edge of the rectangle.

      Available in iOS 7.0 and later.

    • All

      UIRectEdgeAll

      All edges of the rectangle.

      Available in iOS 7.0 and later.

    Discussion

    You can add these constants together to specify multiple edges at the same time.

    Import Statement

    Objective-C

    @import UIKit;

    Swift

    import UIKit

    Availability

    Available in iOS 7.0 and later.

  • Type qualifiers used by Interface Builder to synchronize with Xcode.

    Declaration

    Objective-C

    #define IBAction void #define IBOutlet

    Constants

    • IBAction

      IBAction

      Type qualifier used by Interface Builder to synchronize actions. Use this type as the return type of any action methods defined in your project. For examples of how to use this identifier, see Xcode Integration.

      Available in iOS 2.0 through iOS 3.2.

    • IBOutlet

      IBOutlet

      Identifier used to identify a property so Interface Builder can synchronize the display and connection of outlets with Xcode. Insert this identifier immediately before the type in any declarations. For examples, including how to use it with the @property syntax, see Xcode Integration.

      Available in iOS 2.0 through iOS 3.2.

    Discussion

    For more information about how to use these constants, see Communicating with Objects. For information about defining and using actions and outlets in Interface Builder, see Interface Builder User Guide.