UIButton Class Reference

Inherits from	UIControl : UIView : UIResponder : NSObject
Conforms to	NSCoding NSCoding (UIView) UIAppearance (UIView) UIAppearanceContainer (UIView) NSObject (NSObject)
Framework	/System/Library/Frameworks/UIKit.framework
Availability	Available in iOS 2.0 and later.
Declared in	UIButton.h
Related sample code	AddMusic avTouch Popovers Sampler Unit Presets (LoadPresetDemo) UICatalog

Overview

An instance of the UIButton class implements a button on the touch screen. A button intercepts touch events and sends an action message to a target object when tapped. Methods for setting the target and action are inherited from UIControl. This class provides methods for setting the title, image, and other appearance properties of a button. By using these accessors, you can specify a different appearance for each button state.

For information about basic view behaviors, see View Programming Guide for iOS.

Tasks

Creating Buttons

Configuring the Button Title

Configuring Button Presentation

Configuring Edge Insets

Getting the Current State

Getting Dimensions

Deprecated Properties

Properties

adjustsImageWhenDisabled

A Boolean value that determines whether the image changes when the button is disabled.

@property(nonatomic) BOOL adjustsImageWhenDisabled

Discussion

If YES, the image is drawn darker when the button is disabled. The default value is YES.

Availability

Available in iOS 2.0 and later.

Declared In

UIButton.h

adjustsImageWhenHighlighted

A Boolean value that determines whether the image changes when the button is highlighted.

@property(nonatomic) BOOL adjustsImageWhenHighlighted

Discussion

If YES, the image is drawn lighter when the button is highlighted. The default value is YES.

Availability

Available in iOS 2.0 and later.

Declared In

UIButton.h

buttonType

The button type. (read-only)

@property(nonatomic, readonly) UIButtonType buttonType

Discussion

See UIButtonType for the possible values.

Availability

Available in iOS 2.0 and later.

Declared In

UIButton.h

contentEdgeInsets

The inset or outset margins for the rectangle surrounding all of the button’s content.

@property(nonatomic) UIEdgeInsets contentEdgeInsets

Discussion

Use this property to resize and reposition the effective drawing rectangle for the button content. The content comprises the button image and button title. You can specify a different value for each of the four insets (top, left, bottom, right). A positive value shrinks, or insets, that edge—moving it closer to the center of the button. A negative value expands, or outsets, that edge. Use the UIEdgeInsetsMake function to construct a value for this property. The default value is UIEdgeInsetsZero.

Availability

Available in iOS 2.0 and later.

Declared In

UIButton.h

currentAttributedTitle

The current styled title that is displayed on the button. (read-only)

@property(nonatomic,readonly,retain) NSAttributedString *currentAttributedTitle

Discussion

The value for this property reflects the title associated with the control’s current state. For states that do not have a custom title string associated with them, this method returns the attributed title that is currently displayed, which is typically the one associated with the UIControlStateNormal state.

Availability

Available in iOS 6.0 and later.

Declared In

UIButton.h

currentBackgroundImage

The current background image displayed on the button. (read-only)

@property(nonatomic, readonly, retain) UIImage *currentBackgroundImage

Discussion

This value can be nil.

Availability

Available in iOS 2.0 and later.

Declared In

UIButton.h

currentImage

The current image displayed on the button. (read-only)

@property(nonatomic, readonly, retain) UIImage *currentImage

Discussion

This value can be nil.

Availability

Available in iOS 2.0 and later.

Declared In

UIButton.h

currentTitle

The current title that is displayed on the button. (read-only)

@property(nonatomic, readonly, retain) NSString *currentTitle

Discussion

The value for this property is set automatically whenever the button state changes. For states that do not have a custom title string associated with them, this method returns the title that is currently displayed, which is typically the one associated with the UIControlStateNormal state. The value may be nil.

Availability

Available in iOS 2.0 and later.

Declared In

UIButton.h

currentTitleColor

The color used to display the title. (read-only)

@property(nonatomic, readonly, retain) UIColor *currentTitleColor

Discussion

This value is guaranteed not to be nil. The default value is white.

Availability

Available in iOS 2.0 and later.

Related Sample Code

GKTapper

Declared In

UIButton.h

currentTitleShadowColor

The color of the title’s shadow. (read-only)

@property(nonatomic, readonly, retain) UIColor *currentTitleShadowColor

Discussion

The default value is white.

Availability

Available in iOS 2.0 and later.

Declared In

UIButton.h

imageEdgeInsets

The inset or outset margins for the rectangle around the button’s image.

@property(nonatomic) UIEdgeInsets imageEdgeInsets

Discussion

Use this property to resize and reposition the effective drawing rectangle for the button image. You can specify a different value for each of the four insets (top, left, bottom, right). A positive value shrinks, or insets, that edge—moving it closer to the center of the button. A negative value expands, or outsets, that edge. Use the UIEdgeInsetsMake function to construct a value for this property. The default value is UIEdgeInsetsZero.

Availability

Available in iOS 2.0 and later.

Declared In

UIButton.h

imageView

The button’s image view. (read-only)

@property(nonatomic, readonly, retain) UIImageView *imageView

Discussion

Although this property is read-only, its own properties are read/write. Use these properties to configure the appearance and behavior of the button’s view. For example:

UIButton *button                   = [UIButton buttonWithType: UIButtonTypeRoundedRect];

button.imageView.exclusiveTouch    = YES;

The imageView property returns a value even if the button has not been displayed yet. The value of the property is nil for system buttons.

Availability

Available in iOS 3.0 and later.

Declared In

UIButton.h

reversesTitleShadowWhenHighlighted

A Boolean value that determines whether the title shadow changes when the button is highlighted.

@property(nonatomic) BOOL reversesTitleShadowWhenHighlighted

Discussion

If YES, the shadow changes from engrave to emboss appearance when highlighted. The default value is NO.

Availability

Available in iOS 2.0 and later.

Declared In

UIButton.h

showsTouchWhenHighlighted

A Boolean value that determines whether tapping the button causes it to glow.

@property(nonatomic) BOOL showsTouchWhenHighlighted

Discussion

If YES, the button glows when tapped; otherwise, it does not. The image and button behavior is not changed by the glow. The default value is NO.

Availability

Available in iOS 2.0 and later.

Declared In

UIButton.h

tintColor

The tint color for the button.

@property(nonatomic, retain) UIColor *tintColor

Discussion

The default value is nil.

This property is not valid for all button types.

Availability

Available in iOS 5.0 and later.

Declared In

UIButton.h

titleEdgeInsets

The inset or outset margins for the rectangle around the button’s title text.

@property(nonatomic) UIEdgeInsets titleEdgeInsets

Discussion

Use this property to resize and reposition the effective drawing rectangle for the button title. You can specify a different value for each of the four insets (top, left, bottom, right). A positive value shrinks, or insets, that edge—moving it closer to the center of the button. A negative value expands, or outsets, that edge. Use the UIEdgeInsetsMake function to construct a value for this property. The default value is UIEdgeInsetsZero.

The insets you specify are applied to the title rectangle after that rectangle has been sized to fit the button’s text. Thus, positive inset values may actually clip the title text.

Availability

Available in iOS 2.0 and later.

Declared In

UIButton.h

titleLabel

A view that displays the value of the currentTitle property for a button. (read-only)

@property(nonatomic, readonly, retain) UILabel *titleLabel

Discussion

Although this property is read-only, its own properties are read/write. Use these properties primarily to configure the text of the button. For example:

UIButton *button                  = [UIButton buttonWithType: UIButtonTypeRoundedRect];

button.titleLabel.font            = [UIFont systemFontOfSize: 12];

button.titleLabel.lineBreakMode   = UILineBreakModeTailTruncation;

Do not use the label object to set the text color or the shadow color. Instead, use the setTitleColor:forState: and setTitleShadowColor:forState: methods of this class to make those changes.

The titleLabel property returns a value even if the button has not been displayed yet. The value of the property is nil for system buttons.

Availability

Available in iOS 3.0 and later.

Related Sample Code

GKTapper

Declared In

UIButton.h

Class Methods

buttonWithType:

Creates and returns a new button of the specified type.

+ (id)buttonWithType:(UIButtonType)buttonType

Parameters

buttonType: The button type. See UIButtonType for the possible values.

Return Value

A newly created button.

Discussion

This method is a convenience constructor for creating button objects with specific configurations. It you subclass UIButton, this method does not return an instance of your subclass. If you want to create an instance of a specific subclass, you must alloc/init the button directly.

When creating a custom button—that is a button with the type UIButtonTypeCustom—the frame of the button is set to (0, 0, 0, 0) initially. Before adding the button to your interface, you should update the frame to a more appropriate value.

Availability

Available in iOS 2.0 and later.

Related Sample Code

Declared In

UIButton.h

Instance Methods

attributedTitleForState:

Returns the styled title associated with the specified state.

- (NSAttributedString *)attributedTitleForState:(UIControlState)state

Parameters

state: The state that uses the styled title. The possible values are described in UIControlState.

Return Value

The title for the specified state. If no attributed title has been set for the specific state, this method returns the attributed title associated with the UIControlStateNormal state.

Availability

Available in iOS 6.0 and later.

Declared In

UIButton.h

backgroundImageForState:

Returns the background image used for a button state.

- (UIImage *)backgroundImageForState:(UIControlState)state

Parameters

state: The state that uses the background image. Possible values are described in UIControlState.

Return Value

The background image used for the specified state.

Availability

Available in iOS 2.0 and later.

Declared In

UIButton.h

backgroundRectForBounds:

Returns the rectangle in which the receiver draws its background.

- (CGRect)backgroundRectForBounds:(CGRect)bounds

Parameters

bounds: The bounding rectangle of the receiver.

Return Value

The bounds rectangle in which to draw any standard button content.

Discussion

The default implementation of this method returns the value in the bounds parameter. This rectangle represents the area in which the button draws its standard background content. Subclasses that provide custom background adornments can override this method and return a modified bounds rectangle to prevent the button from drawing over any custom content.

Availability

Available in iOS 2.0 and later.

Declared In

UIButton.h

contentRectForBounds:

Returns the rectangle in which the receiver draws its entire content.

- (CGRect)contentRectForBounds:(CGRect)bounds

Parameters

bounds: The bounding rectangle for the receiver.

Return Value

The rectangle in which the receiver draws its entire content.

Discussion

The content rectangle is the area needed to display the image and title including any padding and adjustments for alignment and other settings.

Availability

Available in iOS 2.0 and later.

Declared In

UIButton.h

imageForState:

Returns the image used for a button state.

- (UIImage *)imageForState:(UIControlState)state

Parameters

state: The state that uses the image. Possible values are described in UIControlState.

Return Value

The image used for the specified state.

Availability

Available in iOS 2.0 and later.

Declared In

UIButton.h

imageRectForContentRect:

Returns the rectangle in which the receiver draws its image.

- (CGRect)imageRectForContentRect:(CGRect)contentRect

Parameters

contentRect: The content rectangle for the receiver.

Return Value

The rectangle in which the receiver draws its image.

Availability

Available in iOS 2.0 and later.

Declared In

UIButton.h

setAttributedTitle:forState:

Sets the styled title to use for the specified state.

- (void)setAttributedTitle:(NSAttributedString *)title forState:(UIControlState)state

Parameters

title: The styled text string so use for the title.
state: The state that uses the specified title. The possible values are described in UIControlState.

Discussion

Use this method to set the title of the button, including any relevant formatting information. If you set both a title and an attributed title for the button, the button prefers the use of the attributed title.

At a minimum, you should set the value for the normal state. If a title is not specified for a state, the default behavior is to use the title associated with the UIControlStateNormal state. If the value for UIControlStateNormal is not set, then the property defaults to a system value.

Availability

Available in iOS 6.0 and later.

Declared In

UIButton.h

setBackgroundImage:forState:

Sets the background image to use for the specified button state.

- (void)setBackgroundImage:(UIImage *)image forState:(UIControlState)state

Parameters

image: The background image to use for the specified state.
state: The state that uses the specified image. The values are described in UIControlState.

Discussion

In general, if a property is not specified for a state, the default is to use the UIControlStateNormal value. If the UIControlStateNormal value is not set, then the property defaults to a system value. Therefore, at a minimum, you should set the value for the normal state.

Availability

Available in iOS 2.0 and later.

Related Sample Code

Declared In

UIButton.h

setImage:forState:

Sets the image to use for the specified state.

- (void)setImage:(UIImage *)image forState:(UIControlState)state

Parameters

image: The image to use for the specified state.
state: The state that uses the specified title. The values are described in UIControlState.

Discussion

Availability

Available in iOS 2.0 and later.

Related Sample Code

Declared In

UIButton.h

setTitle:forState:

Sets the title to use for the specified state.

- (void)setTitle:(NSString *)title forState:(UIControlState)state

Parameters

title: The title to use for the specified state.
state: The state that uses the specified title. The possible values are described in UIControlState.

Discussion

Use this method to set the title for the button. The title you specify derives its formatting from the button’s associated label object. If you set both a title and an attributed title for the button, the button prefers the use of the attributed title over this one.

Availability

Available in iOS 2.0 and later.

Related Sample Code

Declared In

UIButton.h

setTitleColor:forState:

Sets the color of the title to use for the specified state.

- (void)setTitleColor:(UIColor *)color forState:(UIControlState)state

Parameters

color: The color of the title to use for the specified state.
state: The state that uses the specified color. The possible values are described in UIControlState.

Discussion

Availability

Available in iOS 2.0 and later.

Related Sample Code

UICatalog

Declared In

UIButton.h

setTitleShadowColor:forState:

Sets the color of the title shadow to use for the specified state.

- (void)setTitleShadowColor:(UIColor *)color forState:(UIControlState)state

Parameters

color: The color of the title shadow to use for the specified state.
state: The state that uses the specified color. The possible values are described in UIControlState.

Discussion

Availability

Available in iOS 2.0 and later.

Declared In

UIButton.h

titleColorForState:

Returns the title color used for a state.

- (UIColor *)titleColorForState:(UIControlState)state

Parameters

state: The state that uses the title color. The possible values are described in UIControlState.

Return Value

The color of the title for the specified state.

Availability

Available in iOS 2.0 and later.

Declared In

UIButton.h

titleForState:

Returns the title associated with the specified state.

- (NSString *)titleForState:(UIControlState)state

Parameters

state: The state that uses the title. The possible values are described in UIControlState.

Return Value

The title for the specified state. If no title has been set for the specific state, this method returns the title associated with the UIControlStateNormal state.

Availability

Available in iOS 2.0 and later.

Declared In

UIButton.h

titleRectForContentRect:

Returns the rectangle in which the receiver draws its title.

- (CGRect)titleRectForContentRect:(CGRect)contentRect

Parameters

contentRect: The content rectangle for the receiver.

Return Value

The rectangle in which the receiver draws its title.

Availability

Available in iOS 2.0 and later.

Declared In

UIButton.h

titleShadowColorForState:

Returns the shadow color of the title used for a state.

- (UIColor *)titleShadowColorForState:(UIControlState)state

Parameters

state: The state that uses the title shadow color. The possible values are described in UIControlState.

Return Value

The color of the title’s shadow for the specified state.

Availability

Available in iOS 2.0 and later.

Declared In

UIButton.h

Constants

UIButtonType

Specifies the style of a button.

typedef enum {
   UIButtonTypeCustom = 0,
   UIButtonTypeRoundedRect,
   UIButtonTypeDetailDisclosure,
   UIButtonTypeInfoLight,
   UIButtonTypeInfoDark,
   UIButtonTypeContactAdd,
} UIButtonType;