Source

A base class for data source implementations.

Usage

Data sources are abstractions that allow you to define the data being managed by your application independent of the GUI representation of that data. For details on the use of data sources, see the topic guide.

Source isn't useful on its own; it is a base class for data source implementations. It is used by ListSource, TreeSource and ValueSource, but it can also be used by custom data source implementations. It provides an implementation of the notification API that data sources must provide.

Reference

toga.sources.Listener

Bases: Protocol

The protocol that must be implemented by objects that will act as a listener on a data source.

change

change(item: object) -> object

A change has occurred in an item.

PARAMETER	DESCRIPTION
item	The data object that has changed. TYPE: object

clear

clear() -> object

All items have been removed from the data source.

insert

insert(index: int, item: object) -> object

An item has been added to the data source.

PARAMETER	DESCRIPTION
index	The 0-index position in the data. TYPE: int
item	The data object that was added. TYPE: object

remove

remove(index: int, item: object) -> object

An item has been removed from the data source.

PARAMETER	DESCRIPTION
index	The 0-index position in the data. TYPE: int
item	The data object that was added. TYPE: object

toga.sources.Source

Source()

A base class for data sources, providing an implementation of data notifications.

listeners property

listeners: list[Listener]

The listeners of this data source.

RETURNS	DESCRIPTION
list[Listener]	A list of objects that are listening to this data source.

add_listener

add_listener(listener: Listener) -> None

Add a new listener to this data source.

If the listener is already registered on this data source, the request to add is ignored.

PARAMETER	DESCRIPTION
listener	The listener to add TYPE: Listener

notify

notify(notification: str, **kwargs: object) -> None

Notify all listeners an event has occurred.

PARAMETER	DESCRIPTION
notification	The notification to emit. TYPE: str
kwargs	The data associated with the notification. TYPE: object DEFAULT: {}

remove_listener

remove_listener(listener: Listener) -> None

Remove a listener from this data source.

PARAMETER	DESCRIPTION
listener	The listener to remove. TYPE: Listener