Dash: Keypress callback

[mflevine]

I would like to be able to capture keypresses and use them for callbacks. This could be used to make keyboard shortcuts in place of buttons.

[Jaudouard]

Perhaps a hidden input field with autofocus on ?
You would have several callbacks listening to this input and executing code accordingly.

I guess you would have to add an extra callback dedicated to clearing the input field everytime it is filled with something as well.

[mflevine]

Seems pretty hacky this way. Wont the input field lose focus as soon as the user starts interacting with other inputs?

[Jaudouard]

You are right, pretty hacky...

[konstantinmiller]

Oh, I'm a bit surprised. Is there no way one can create callbacks for keyboard events? That seems like a basic interaction pattern.

[emilhe]

You could try the Keyboard component in dash-extensions,

import dash
import dash_html_components as html
import json

from dash.dependencies import Output, Input
from dash_extensions import Keyboard

app = dash.Dash()
app.layout = html.Div([Keyboard(id="keyboard"), html.Div(id="output")])


@app.callback(Output("output", "children"), [Input("keyboard", "keydown")])
def keydown(event):
    return json.dumps(event)


if __name__ == '__main__':
    app.run_server()

https://pypi.org/project/dash-extensions/

[alexcjohnson]

@emilhe Thanks for pointing out dash-extensions - lots of good stuff there! Some overlap with functionality we're already working on (eg flattened callback args https://github.com/plotly/dash/pull/1180) and other things we haven't started on but have discussed. In particular Trigger https://github.com/plotly/dash/issues/1054 is something we're very interested in adding to Dash itself, and Keyboard would be a great addition to dash-core-components. You're of course welcome to continue developing these features separately under dash-extensions but if you're interested to PR the more generally-applicable features into Dash or dash-core-components directly, we'd be glad to help 😎

[emilhe]

@alexcjohnson Thanks! As the components mature, i think it would be good (in particular for new users), if they were moved to dash-core-components. The Trigger component would probably be a good place to start (it is pretty simple), but i feel (based on community feedback) that the functionality provided by the Download and ServersideOutput components are even more needed. When i find some time, i'll take a look at the contribution guidelines :)