Button

macOS

GTK+

Windows

iOS

Android

Django

y

y

y

y

y

y

The button is a clickable node that fires a callback method when pressed or clicked.

../../../_images/Button.jpeg

Usage

The most basic button has a text label and a callback method for when it is pressed. The callback expects 1 argument, the instance of the button firing the event.

import toga

def my_callback(button):
    # handle event
    pass

button = toga.Button('Click me', on_press=my_callback)

Reference

class toga.widgets.button.Button(label, id=None, style=None, on_press=None, enabled=True, factory=None)

A clickable button widget.

Parameters
  • label (str) – Text to be shown on the button.

  • id (str) – An identifier for this widget.

  • style (Style) – An optional style object. If no style is provided then a new one will be created for the widget.

  • on_press (callable) – Function to execute when pressed.

  • enabled (bool) – Whether or not interaction with the button is possible, defaults to True.

  • factory (module) – A python module that is capable to return a implementation of this class with the same name. (optional & normally not needed)

add(*children)

Add nodes as children of this one. If a node already has a different parent, it will be moved over. This does nothing if a node already is a child of this node.

Parameters

children – Nodes to add as children of this node.

Raises

ValueError – If this node is a leaf, and cannot have children.

property app

The App to which this widget belongs. On setting the app we also iterate over all children of this widget and set them to the same app.

Returns

The toga.App to which this widget belongs.

Raises

ValueError – If the widget is already associated with another app.

property can_have_children

Determine if the node can have children.

This does not resolve whether there actually are any children; it only confirms whether children are theoretically allowed.

property children

The children of this node. This always returns a list, even if the node is a leaf and cannot have children.

Returns

A list of the children for this widget.

property enabled
focus()
property id

The node identifier. This id can be used to target styling directives

Returns

The widgets identifier as a str.

insert(index, child)

Insert a node as a child of this one. If the node already has a different parent, it will be moved over. This does nothing if the node already is a child of this node.

Parameters
  • index – Position of child node.

  • child – A node to insert as a child of this node.

Raises

ValueError – If this node is a leaf, and cannot have children.

property label

Returns: The button label as a str

property on_press

The handler to invoke when the button is pressed.

Returns

The function callable that is called on button press.

property parent

The parent of this node.

Returns

The parent of this node. Returns None if this node is the root node.

refresh()

Refresh the layout and appearance of the tree this node is contained in.

refresh_sublayouts()
remove(*children)

Remove child nodes of this node. This does nothing if a given node is not a child of this node.

Parameters

children – Child nodes to remove.

Raises

ValueError – If this node is a leaf, and cannot have children.

property root

The root of the tree containing this node.

Returns

The root node. Returns self if this node is the root node.

property window

The Window to which this widget belongs. On setting the window, we automatically update all children of this widget to belong to the same window.

Returns

The toga.Window to which the widget belongs.