Connecting a click event on a widget to a function.

[JoeZiminski]

Is it possible to connect a function to a click event on a specific widget? In particular, I am interested in linking a function execution to double-clicking on a particular Input widget. As far as I can see, the _on_click() method of Input does not have any kind of emit signal and the generic on_click method does not need to hold information about the clicked widget. I presume it is possible based on the x,y position of the click and widget but was wondering if there is an easier way.

Apologies if this is an obvious question, I could not find an answer after a reasonably thorough search of docs / issues but I may be looking for the wrong thing!

[davep]

If it's a specific widget you want to do this for, you could subclass that widget and handle it from there, adding your own Clicked message. For example:

from __future__ import annotations
from dataclasses import dataclass

from textual import on
from textual.app import App, ComposeResult
from textual.events import Click
from textual.message import Message
from textual.widgets import Input, Log

class ClickableInput(Input):

    @dataclass
    class Clicked(Message):
        input: ClickableInput

    def _on_click(self, _: Click) -> None:
        self.post_message(self.Clicked(self))


class InputClickApp(App[None]):

    def compose(self) -> ComposeResult:
        yield ClickableInput()
        yield Log()

    @on(ClickableInput.Clicked)
    def log_click(self, event: ClickableInput.Clicked) -> None:
        self.query_one(Log).write_line(f"{event!r}")

if __name__ == "__main__":
    InputClickApp().run()

More generally, you could use get_widget_at to get the widget that was clicked, and use it at a higher level in the DOM; unfortunately though if the widget being clicked is processing and stopping the event, it'll never bubble up. For example:

from textual.app import App, ComposeResult
from textual.events import Click
from textual.widgets import Input, Label, Button

class ClickAnywhereApp(App[None]):

    def compose(self) -> ComposeResult:
        for n in range(10):
            yield Input(id=f"input-{n}")
            yield Label(f"Label {n}", id=f"label-{n}")
            yield Button(f"Button {n}", id=f"button-{n}")

    async def _on_click(self, event: Click) -> None:
        self.notify(f"{self.get_widget_at(event.screen_x, event.screen_y)[0]}")

if __name__ == "__main__":
    ClickAnywhereApp().run()

You'll always get a notification from the screen and the labels, but never from the Button or the Input (actually, in testing, I was seeing the occasional one from the Input which is kind of odd).

But, if as you say:

I am interested in linking a function execution to double-clicking on a particular Input widget

then you could roll your own subclass of Input like the above and you should be good to go. Note though that Textual doesn't have a double-click event.

[JoeZiminski]

Thanks a lot @davep for the detailed and very prompt response! I will try this out today and let you know if anything comes up. Cheers!

[JoeZiminski]

Thanks @davep works like a dream! I had one question, I see it is not necessary to also call the method on the super class e.g.
super(ClickableInput, self)._on_click() to get the superclass functionality. It this becuse it is an async function?

[davep]

Not because of async, but because Textual handles that on purpose for you. Which may lead to the next obvious question: how to stop it doing that when you don't want it to.

[JoeZiminski]

That makes sense, that is a nice design! thanks for all your help.