在 Python + Dash 中禁用 "Submit" 按钮 30 秒

Question

我想阻止用户在下面的脚本中按下 "Submit" 按钮 30 秒。我该怎么做呢？这是我的代码目前的样子：

import dash
from dash.dependencies import Input, Output, State
import dash_core_components as dcc
import dash_html_components as html

app = dash.Dash()

app.layout = html.Div([
    dcc.Input(id='my-id', value='initial value', type="text"),
    html.Button('Submit', id='button'),
    html.Div(id='my-div')
])

@app.callback(
    Output(component_id='my-div', component_property='children'),
    [Input('button', 'n_clicks')],
    state=[State(component_id='my-id', component_property='value')]
)
def update_output_div(n_clicks, input_value):
    return 'You\'ve entered "{}" and clicked {} times'.format(input_value, n_clicks)

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

有谁知道如何阻止用户按下按钮 30 秒？

提前致谢。

编辑 15/08/2018 9:30AM GMT 对 stevepastelan 的回应：

import dash
from dash.dependencies import Input, Output, State
import dash_core_components as dcc
import dash_html_components as html

app = dash.Dash()

app.layout = html.Div([
    dcc.Input(id='my-id', value='initial value', type="text"),
    html.Button('Submit', id='button'),
    html.Div([dcc.Interval(
        id='interval-component',
        interval=1 * 3000,  # in milliseconds
        n_intervals=0
)]),
    html.Div(id='my-div')
])

@app.callback(
    Output(component_id='my-div', component_property='children'),
    [Input('button', 'n_clicks')], [Input('interval-component', 'n_intervals')],
    state=[State(component_id='my-id', component_property='value')]
)
def update_output_div(n_clicks,n_intervals, input_value):
    return 'You\'ve entered "{}" and clicked {} times'.format(input_value, n_clicks)

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

编辑 15/08/2018 16:22PM 使用编辑后的回调编写了更简单的脚本，但它不起作用：

import dash
from dash.dependencies import Input, Output, State
import dash_core_components as dcc
import dash_html_components as html

app = dash.Dash()

app.layout = html.Div([
    dcc.Input(id='my-id', value='initial value', type="text"),
    html.Button('Submit', id='button'),
    html.Div([dcc.Interval(
        id='interval-component',
        interval=1 * 3000,  # in milliseconds
        n_intervals=0
)]),
    html.Div(id='my-div')
])

@app.callback(
    Output(component_id='my-div', component_property='children'),
    [Input('button', 'n_clicks')], [Input('interval-component', 'n_intervals')],
    state=[State(component_id='my-id', component_property='value')]
)

def update_output_div(n_clicks,n_intervals, input_value):
    return 'You\'ve entered "{}" and clicked {} times'.format(input_value, n_clicks)

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

Answer 1

更新答案

好吧，我设法实现了自己的建议，但这并不简单，而且仍然有怪癖。

复杂因素是：

Dash 不允许两个回调指向同一个 Output
没有很好的方法来跟踪哪个 Input 或 Event 触发了您的回调。解决方法通常涉及跟踪每个按钮的点击次数（参见 https://github.com/plotly/dash-html-components/pull/37 作为示例）。
通过 disable=True 或 max_requests=0 禁用计时器似乎是永久性的。以这种方式停止计时器后，我无法使用 disable=False 或 max_requests=1000.

问题：

在这个解决方案中，update_output_div() 被调用了两次 -- 但您可以通过测量按钮点击次数与之前的计数来区分两者，这样您就可以避免它提交您的数据两次.
小于 100 毫秒的超时将不起作用。我必须拆分延迟计时器才能使我的方法起作用，因此我选择 100 和 (1000 * BUTTON_PRESS_LOCKOUT_SECONDS)-100 作为两个计时器持续时间。原则上，您可以将它们平均分成一半。我不知道在网络上工作时使用低超时是否有任何问题（我在本地主机上进行了测试）。

灵感来自：

import json
import datetime

import dash
from dash.dependencies import Input, Output, State, Event
import dash_core_components as dcc
import dash_html_components as html

BUTTON_PRESS_LOCKOUT_SECONDS = 10  # seconds

app = dash.Dash()
app.config['suppress_callback_exceptions']=True

def serve_layout():
    return html.Div([
        dcc.Input(id='my-id', value='initial value', type="text"),
        html.Button('Submit', id='button'),
        html.Div(
              [
                  dcc.Interval(id='interval-component', disabled=True)
                , dcc.Interval(id='interval-sync-component', disabled=True)
              ]
            , id='interval-container'
        ),
        html.Div("", id='my-div'),
        html.Div(json.dumps({'n_clicks':0, 'n_previous_clicks':0}), id='local_data'),
        html.Div('??', id='button-status'),
    ])

app.layout = serve_layout

# Track button clicks
@app.callback(
    output=Output(component_id='local_data', component_property='children'),
    inputs=[Input('button', 'n_clicks')],
    state=[State('local_data', 'children')],
    events=[Event('interval-sync-component', 'interval')]
)
def track_clicks(n_clicks, local_data_json):
    if n_clicks is None:
        n_clicks = 0

    local_data = json.loads(local_data_json)
    n_previous_clicks = local_data['n_clicks']

    # Update local data with the new click data
    local_data.update(**{'n_clicks': n_clicks, 'n_previous_clicks': n_previous_clicks})
    # local_data.update(**{'n_clicks': n_clicks, 'n_previous_clicks': n_previous_clicks})
    return json.dumps(local_data)


# When the button click count is updated, submit
@app.callback(
    output=Output(component_id='my-div', component_property='children'),
    inputs=[Input('local_data', 'children')],
    state=[State(component_id='my-id', component_property='value'), State('my-div', 'children')]
)
def update_output_div(local_data_json, input_value, current_state):
    local_data = json.loads(local_data_json)
    n_clicks = local_data['n_clicks']
    n_previous_clicks = local_data['n_previous_clicks']

    # Real submit
    if n_clicks > n_previous_clicks:
        return 'You\'ve entered "{}" and clicked {} times ({})'.format(
              input_value
            , n_clicks if n_clicks is not None else 0
            , datetime.datetime.now()
        )

    # Not a real submit, but function is called an extra time as a side effect of the timer nonsense below.
    else:
        return '*' + current_state


# Start (or stop) the timer
@app.callback(
    output=Output('interval-container', 'children'),
    inputs=[Input('local_data', 'children')],
    state=[State('button', 'disabled')],
    events=[Event('interval-component', 'interval')]
)
def start_timer(local_data_json, button_is_disabled):
    local_data = json.loads(local_data_json)
    n_clicks = local_data['n_clicks']
    n_previous_clicks = local_data['n_previous_clicks']

    children=[]

    if n_clicks > n_previous_clicks:
        sync_timer = dcc.Interval(
            id='interval-sync-component',
            interval=100,  # in milliseconds
        )
        children.append(sync_timer)

    if button_is_disabled:
        main_timer = dcc.Interval(
            id='interval-component',
            interval=(1000 * BUTTON_PRESS_LOCKOUT_SECONDS)-100,  # in milliseconds
        )
        children.append(main_timer)

    return children


# Enable the button whenever the timer interval is triggered or disable it when the button is pressed
@app.callback(
    output=Output('button', 'disabled'),
    inputs=[Input('button', 'n_clicks')],
    state=[State('local_data', 'children')],
    events=[Event('interval-component', 'interval')]
)
def toggle_button_disabled_state(n_clicks, local_data_json):
    local_data = json.loads(local_data_json)
    # n_clicks = local_data['n_clicks']
    if n_clicks is None:
        n_clicks = 0
    n_previous_clicks = local_data['n_previous_clicks']

    # We got here via button click, so disable the button
    if n_clicks > n_previous_clicks:
        return True

    # We got here via timer expiration, so enable the button
    else:
        return False  # enable the button

# Report on the button status
@app.callback(
    output=Output('button-status', 'children'),
    inputs=[Input('button', 'disabled')]
)
def update_button_status(disabled):
    if disabled:
        return 'Disabled submit button for {} seconds'.format(BUTTON_PRESS_LOCKOUT_SECONDS)
    else:
        return 'Submit button enabled'


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

原回答

您可以使用 dash_core_components.Interval 根据计时器触发要在页面上执行的操作。这里有一些例子：https://dash.plot.ly/live-updates

您可以使用 n_intervals = 0 初始化您的间隔组件，然后让您的提交按钮自行禁用并设置 n_intervals = 1。然后在重新启用按钮的时间间隔上编写回调。

在 Python + Dash 中禁用 "Submit" 按钮 30 秒

Disable "Submit" button for 30 seconds in Python + Dash

python

plotly-dash

更新答案

原回答