Events

events

Compose

Bases: Event

Sent to a widget to request it to compose and mount children.

Event

Bases: Message

The base class for all events.

Hide

Bases: Event

Sent when a widget has been hidden.

A widget may be hidden by setting its visible flag to False, if it is no longer in a layout, or if it has been offset beyond the edges of the terminal.

Idle

Bases: Event

Sent when there are no more items in the message queue.

This is a pseudo-event in that it is created by the Textual system and doesn't go through the usual message queue.

InputEvent

Bases: Event

Base class for input events.

InvokeCallbacks

Bases: Event

Sent after the Screen is updated

Key

Bases: InputEvent

Sent when the user hits a key on the keyboard.

Parameters:

Name	Type	Description	Default
key	str	The key that was pressed.	required
character	str | None	A printable character or None if it is not printable.	required

Attributes:

Name	Type	Description
aliases	list[str]	The aliases for the key, including the key itself.

is_printable: bool property

Check if the key is printable (produces a unicode character).

Returns:

Type	Description
bool	True if the key is printable.

name: str property

Name of a key suitable for use as a Python identifier.

name_aliases: list[str] property

The corresponding name for every alias in aliases list.

Load

Bases: Event

Sent when the App is running but before the terminal is in application mode.

Use this event to run any set up that doesn't require any visuals such as loading configuration and binding keys.

Mount

Bases: Event

Sent when a widget is mounted and may receive messages.

MouseCapture

Bases: Event

Sent when the mouse has been captured.

When a mouse has been captured, all further mouse events will be sent to the capturing widget.

Parameters:

Name	Type	Description	Default
mouse_position	Offset	The position of the mouse when captured.	required

MouseEvent

Bases: InputEvent

Sent in response to a mouse event.

Parameters:

Name	Type	Description	Default
x	int	The relative x coordinate.	required
y	int	The relative y coordinate.	required
delta_x	int	Change in x since the last message.	required
delta_y	int	Change in y since the last message.	required
button	int	Indexed of the pressed button.	required
shift	bool	True if the shift key is pressed.	required
meta	bool	True if the meta key is pressed.	required
ctrl	bool	True if the ctrl key is pressed.	required
screen_x	int | None	The absolute x coordinate.	None
screen_y	int | None	The absolute y coordinate.	None
style	Style | None	The Rich Style under the mouse cursor.	None

delta: Offset property

Mouse coordinate delta (change since last event).

Returns:

Type	Description
Offset	Mouse coordinate.

offset: Offset property

The mouse coordinate as an offset.

Returns:

Type	Description
Offset	Mouse coordinate.

screen_offset: Offset property

Mouse coordinate relative to the screen.

Returns:

Type	Description
Offset	Mouse coordinate.

style: Style writable property

The (Rich) Style under the cursor.

get_content_offset(widget)

Get offset within a widget's content area, or None if offset is not in content (i.e. padding or border).

Parameters:

Name	Type	Description	Default
widget	Widget	Widget receiving the event.	required

Returns:

Type	Description
Offset | None	An offset where the origin is at the top left of the content area.

MouseMove

Bases: MouseEvent

Sent when the mouse cursor moves.

MouseRelease

Bases: Event

Mouse has been released.

Parameters:

Name	Type	Description	Default
mouse_position	Offset	The position of the mouse when released.	required

Paste

Bases: Event

Event containing text that was pasted into the Textual application. This event will only appear when running in a terminal emulator that supports bracketed paste mode. Textual will enable bracketed pastes when an app starts, and disable it when the app shuts down.

Parameters:

Name	Type	Description	Default
text	str	The text that has been pasted.	required

Ready

Bases: Event

Sent to the app when the DOM is ready.

Resize

Bases: Event

Sent when the app or widget has been resized.

Parameters:

Name	Type	Description	Default
size	Size	The new size of the Widget.	required
virtual_size	Size	The virtual size (scrollable size) of the Widget.	required
container_size	Size | None	The size of the Widget's container widget. Defaults to None.	None

Show

Bases: Event

Sent when a widget has become visible.

Unmount

Bases: Mount

Sent when a widget is unmounted and may not longer receive messages.