Bokeh: textInput on_change function on widget doesn't work as expected

Question

my short script looks like the following:

output_server('ts_sample.html')

count = 0
def update_title(attrname, old, new):
    global count
    count = count + 1

textInput = TextInput(title="query_parameters", name='fcp_chp_id', value='fcp_chp_id')
textInput.on_change('value', update_title)

curdoc().add_root(textInput)
p = figure( width=800, height=650,title="ts_sample",x_axis_label='datetime' )
p.line(np.array(data['date_trunc'].values, dtype=np.datetime64), data['latitude'], legend="test")
p.xaxis[0].formatter=bkmodels.formatters.DatetimeTickFormatter(formats=dict(hours=["%F %T"]))
show(curdoc())

It works, when bokeh server(bokeh serve) is running and I got the plotting, but on_change callback doesn't work as expected.

Assumed the value of textInput should be the content/string in the input box, but I changed it multiple times but the callback function update_title is never called (the count global variable is always 0). So apparently the underlying textInput.value is not changed, how can I change value attr and trigger the on_change function ?

Marc Compere · Accepted Answer · 2020-05-03 09:12:00Z

Here's a simple TextInput example using a callback rather than .on_change(). This might be more helpful for beginners like me than the OP. I very slightly modified the slider example from

http://docs.bokeh.org/en/latest/docs/user_guide/interaction/callbacks.html#customjs-for-model-property-events

from bokeh.layouts import column
from bokeh.models import CustomJS, ColumnDataSource, Slider
from bokeh.models import TextInput
from bokeh.plotting import figure, show

x = [x*0.005 for x in range(0, 200)]
y = x

source = ColumnDataSource(data=dict(x=x, y=y))

plot = figure(plot_width=400, plot_height=400)
plot.line('x', 'y', source=source, line_width=3, line_alpha=0.6)

callback = CustomJS(args=dict(source=source), code="""
        var data = source.get('data');
        var f = cb_obj.get('value')
        x = data['x']
        y = data['y']
        for (i = 0; i < x.length; i++) {
            y[i] = Math.pow(x[i], f)
        }
        source.trigger('change');
    """)

#slider = Slider(start=0.1, end=4, value=1, step=.1, title="power", callback=callback)
#layout = vform(slider, plot)

text_input = TextInput(value="1", title="power", callback=callback)
layout = column(text_input, plot)

show(layout)

A Laurent · Accepted Answer · 2015-12-08 10:50:46Z

2

I have the same problem as you . After search, the on_change function not working with bokeh 0.10 realease but with the upcoming version 0.11 .

From : https://groups.google.com/a/continuum.io/forum/#!topic/bokeh/MyztWSef4tI

If you are using the (new) Bokeh server in the latest dev builds, you can follow this example, for instance: https://github.com/bokeh/bokeh/blob/master/examples/app/sliders.py

From : https://groups.google.com/a/continuum.io/forum/#!topic/bokeh/PryxrZPX2QQ

The server has recently been completely re-written from the ground up and is faster, smaller/simpler, and much easier to use and deploy and explain. The major PR was just merged into master, and will show up in the upcoming 0.11 release in December

For download the dev version : https://anaconda.org/bokeh/bokeh/files

answered Dec 8, 2015 at 10:50

A Laurent

1742 silver badges8 bronze badges

1 Comment

Hello lad Over a year ago

@A Laurent thx for the information, waiting for version 0.11

Thibault Maridor · Accepted Answer · 2020-04-16 09:23:29Z

1

I adapt the example, it may be helpful:

from bokeh.layouts import column
from bokeh.models import TextInput
from bokeh.models import CustomJS, ColumnDataSource, Slider
from bokeh.plotting import figure, show

x = [x*0.005 for x in range(0, 200)]
y = x

source = ColumnDataSource(data=dict(x=x, y=y))

plot = figure(plot_width=400, plot_height=400)
plot.line('x', 'y', source=source, line_width=3, line_alpha=0.6)

callback = CustomJS(args=dict(source=source), code="""
        var data = source.data;
        var f = cb_obj.value;
        x = data['x']
        y = data['y']
        for (i = 0; i < x.length; i++) {
            y[i] = Math.pow(x[i], f)
        }
        source.change.emit();
    """)

#slider = Slider(start=0.1, end=4, value=1, step=.1, title="power", callback=callback)
#layout = vform(slider, plot)

text_input = TextInput(value="1", title="power", callback=callback)
layout = column(text_input, plot)

show(layout)

answered Apr 16, 2020 at 9:23

Thibault Maridor

111 bronze badge

1 Comment

Marc Compere Over a year ago

this works as-expected in bokeh 1.4.0. example above does not

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