Button

A button is a control that contains a text string, and is one of the most common elements of a GUI.

It may be placed on a dialog box or on a Panel panel, or indeed on almost any other window.

By default, i.e. if none of the alignment styles are specified, the label is centered both horizontally and vertically. If the button has both a label and a bitmap, the alignment styles above specify the location of the rectangle combining both the label and the bitmap and the bitmap position set with Button.SetBitmapPosition defines the relative position of the bitmap with respect to the label (however currently non-default alignment combinations are not implemented on all platforms).

Since version 2.9.1 Button supports showing both text and an image (currently only when using wxMSW, wxGTK or OSX/Cocoa ports), see SetBitmap and SetBitmapLabel, SetBitmapDisabled &c methods. In the previous wxWidgets versions this functionality was only available in (the now trivial) BitmapButton class which was only capable of showing an image without text.

A button may have either a single image for all states or different images for the following states (different images are not currently supported under OS X where the normal image is used for all states):

• normal: the default state
• disabled: bitmap shown when the button is disabled.
• pressed: bitmap shown when the button is pushed (e.g. while the user keeps the mouse button pressed on it)
• focus: bitmap shown when the button has keyboard focus (but is not pressed as in this case the button is in the pressed state)
• current: bitmap shown when the mouse is over the button (but it is not pressed although it may have focus). Notice that if current bitmap is not specified but the current platform UI uses hover images for the buttons (such as Windows XP or GTK+), then the focus bitmap is used for hover state as well. This makes it possible to set focus bitmap only to get reasonably good behaviour on all platforms.

All of the bitmaps must be of the same size and the normal bitmap must be set first (to a valid bitmap), before setting any other ones. Also, if the size of the bitmaps is changed later, you need to change the size of the normal bitmap before setting any other bitmaps with the new size (and you do need to reset all of them as their original values can be lost when the normal bitmap size changes).

The position of the image inside the button be configured using SetBitmapPosition. By default the image is on the left of the text.

Please also notice that GTK+ uses a global setting called gtk-button-images to determine if the images should be shown in the buttons at all. If it is off (which is the case in e.g. Gnome 2.28 by default), no images will be shown, consistently with the native behaviour.

Window Styles

This class supports the following styles:

• BU_LEFT: Left-justifies the label. Windows and GTK+ only.
• BU_TOP: Aligns the label to the top of the button. Windows and GTK+ only.
• BU_RIGHT: Right-justifies the bitmap label. Windows and GTK+ only.
• BU_BOTTOM: Aligns the label to the bottom of the button. Windows and GTK+ only.
• BU_EXACTFIT: Creates the button as small as possible instead of making it of the standard size (which is the default behaviour ).
• BU_NOTEXT: Disables the display of the text label in the button even if it has one or its id is one of the standard stock ids with an associated label: without using this style a button which is only supposed to show a bitmap but uses a standard id would display a label too.
• BORDER_NONE: Creates a button without border. This is currently implemented in MSW, GTK2 and OSX/Cocoa and OSX/Carbon ports but in the latter only applies to buttons with bitmaps and using bitmap of one of the standard sizes only, namely 128128, 4848, 2424 or 1616. In all the other cases BORDER_NONE is ignored under OSX/Carbon (these restrictions don’t exist in OSX/Cocoa however).

Events Emitted by this Class

Handlers bound for the following event types will receive a CommandEvent parameter.

• EVT_BUTTON: Process a wxEVT_COMMAND_BUTTON_CLICKED event, when the button is clicked.

See also

BitmapButton

Inheritance Diagram

Inheritance diagram for class Button

Control Appearance

wxMSW

wxMAC

wxGTK

Known Subclasses

BitmapButton, CommandLinkButton

Methods Summary

__init__	Default constructor.
Create	Button creation function for two-step creation.
GetAuthNeeded	Returns True if an authentication needed symbol is displayed on the button.
GetDefaultSize	Returns the default size for the buttons.
GetLabel	Returns the string label for the button.
SetAuthNeeded	Sets whether an authentication needed symbol should be displayed on the button.
SetDefault	This sets the button to be the default item in its top-level window (e.g.
SetLabel	Sets the string label for the button.

Properties Summary

AuthNeeded	See GetAuthNeeded and SetAuthNeeded
Label	See GetLabel and SetLabel

Class API

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class Button(AnyButton)

A button is a control that contains a text string, and is one of the most common elements of a GUI.

Possible constructors:

Button()

Button(parent, id=ID_ANY, label='', pos=DefaultPosition,
       size=DefaultSize, style=0, validator=DefaultValidator,
       name=ButtonNameStr)

Methods

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__init__(self, *args, **kw)

Overloaded Implementations:

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__init__ (self)

Default constructor.

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__init__ (self, parent, id=ID_ANY, label=’‘, pos=DefaultPosition, size=DefaultSize, style=0, validator=DefaultValidator, name=ButtonNameStr)

Constructor, creating and showing a button.

The preferred way to create standard buttons is to use default value of label. If no label is supplied and id is one of standard IDs from this list, a standard label will be used. In other words, if you use a predefined ID_XXX constant, just omit the label completely rather than specifying it. In particular, help buttons (the ones with id of ID_HELP ) under Mac OS X can’t display any label at all and while Button will detect if the standard “Help” label is used and ignore it, using any other label will prevent the button from correctly appearing as a help button and so should be avoided.

In addition to that, the button will be decorated with stock icons under GTK+ 2.

Parameters:

• parent (Window) – Parent window. Must not be None.
• id (int) – Button identifier. A value of ID_ANY indicates a default value.
• label (string) – Text to be displayed on the button.
• pos (Point) – Button position.
• size (Size) – Button size. If the default size is specified then the button is sized appropriately for the text.
• style (long) – Window style. See Button class description.
• validator (Validator) – Window validator.
• name (string) – Window name.

See also

Create , Validator

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Create(self, parent, id=ID_ANY, label='', pos=DefaultPosition, size=DefaultSize, style=0, validator=DefaultValidator, name=ButtonNameStr)

Button creation function for two-step creation.

For more details, see Button .

Parameters:

• parent (Window) –
• id (int) –
• label (string) –
• pos (Point) –
• size (Size) –
• style (long) –
• validator (Validator) –
• name (string) –

Return type:

bool

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GetAuthNeeded(self)

Returns True if an authentication needed symbol is displayed on the button.

Return type:bool

New in version 2.9.1.

Note

This method always returns False if the platform is not Windows Vista or newer.

See also

SetAuthNeeded

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static GetDefaultSize()

Returns the default size for the buttons.

It is advised to make all the dialog buttons of the same size and this function allows to retrieve the (platform and current font dependent size) which should be the best suited for this.

Return type: Size

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GetLabel(self)

Returns the string label for the button.

Return type:string

See also

SetLabel

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SetAuthNeeded(self, needed=True)

Sets whether an authentication needed symbol should be displayed on the button.

Parameters:needed (bool) –

New in version 2.9.1.

Note

This method doesn’t do anything if the platform is not Windows Vista or newer.

See also

GetAuthNeeded

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SetDefault(self)

This sets the button to be the default item in its top-level window (e.g.

the panel or the dialog box containing it).

As normal, pressing return causes the default button to be depressed when the return key is pressed.

See also Window.SetFocus which sets the keyboard focus for windows and text panel items, and TopLevelWindow.SetDefaultItem .

Return type: Window Returns:the old default item (possibly None)

Note

Under Windows, only dialog box buttons respond to this function.

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SetLabel(self, label)

Sets the string label for the button.

Parameters:label (string) – The label to set.

Properties

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AuthNeeded

See GetAuthNeeded and SetAuthNeeded

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Label

See GetLabel and SetLabel