[Python-ideas] A GUI for beginners and experts alike

[Wes Turner]

ipywidgets and toga* implementations of the ABC demo:

| source: https://github.com/westurner/guidemo

# ipywidgetsdemo/ipywidgets_abc_demo.py (.ipynb)

# # ipywidgets ABC demo
# - Update an output widget with the sum of two input widgets when the
'change' event fires

# In[1]:
# https://ipywidgets.readthedocs.io/en/latest/examples/Using%20Interact.html
# https://ipywidgets.readthedocs.io/en/latest/examples/Widget%20List.html
from ipywidgets import interact
import ipywidgets as widgets
def add(x, y):
    return sum((x,y))
widget_x = widgets.IntText(value=0, description='#1')
widget_y = widgets.IntText(value=0, description='#2')
interact(add, x=widget_x, y=widget_y)


# In[2]:
#
https://ipywidgets.readthedocs.io/en/latest/examples/Widget%20Events.html#Registering-callbacks-to-trait-changes-in-the-kernel
from IPython.display import display
from ipywidgets import interact
import ipywidgets as widgets

widget_x = widgets.IntText(value=0, description='#1')
widget_y = widgets.IntText(value=0, description='#2')
widget_sigma = widgets.IntText(value=0, description='sum')

def add_event(event):
    widget_sigma.value = sum((widget_x.value, widget_y.value))

widget_x.observe(add_event, names='value')
widget_y.observe(add_event, names='value')

display(widgets.HBox([widget_x, widget_y, widget_sigma]))




# togaabcdemo/app.py

import toga
from toga.style import Pack
from toga.style.pack import COLUMN, ROW


class TogaAbcDemo(toga.App):

    def add_numbers(self, widget):
        # TODO: validate that n*_input.value are numbers
        n1, n2 = self.n1_input.value, self.n2_input.value
        n3 = sum(n1, n2) if ((n1 is not None) and (n2 is not None)) else
None
        print("%r + %r = %r" % (n1, n2, n3))
        self.n3_input.value = n3

    def startup(self):
        # Create a main window with a name matching the app
        self.main_window = toga.MainWindow(title=self.name)

        # Create a main content box
        main_box = toga.Box()

        self.n1_input = toga.TextInput(
            placeholder='#1',
            on_change=self.add_numbers)
        self.n2_input = toga.TextInput(
            placeholder='#2',
            on_change=self.add_numbers)
        self.n3_input = toga.TextInput(
            placeholder='Sum',
            readonly=True)

        main_box.add(self.n1_input)
        main_box.add(self.n2_input)
        main_box.add(self.n3_input)

        # Add the content on the main window
        self.main_window.content = main_box

        # Show the main window
        self.main_window.show()


def main():
    return TogaAbcDemo('Toga ABC Demo',
'org.westurner.togaabcdemo.togaabcdemo')



On Fri, Aug 24, 2018 at 4:12 AM Wes Turner <wes.turner at gmail.com> wrote:

>
>
> On Thursday, August 23, 2018, Jonathan Fine <jfine2358 at gmail.com> wrote:
>
>> Hi Mike
>>
>> Thank you for your prompt response. You wrote
>>
>> > Maybe we're on different planes?
>> >
>> > I'm talking about 5 lines of Python code to get a custom layout GUI on
>> the screen:
>> >
>> > import PySimpleGUI as sg
>> >
>> > form = sg.FlexForm('Simple data entry form')  # begin with a blank form
>> >
>> > layout = [
>> >           [sg.Text('Please enter your Name, Address, Phone')],
>> >           [sg.Text('Name', size=(15, 1)), sg.InputText('1',
>> key='name')],
>> >           [sg.Text('Address', size=(15, 1)), sg.InputText('2',
>> key='address')],
>> >           [sg.Text('Phone', size=(15, 1)), sg.InputText('3',
>> key='phone')],
>> >           [sg.Submit(), sg.Cancel()]
>> >          ]
>> >
>> > button, values = form.LayoutAndRead(layout)
>>
>> The execution of this code, depends on PySimpleGUI, which in turn depends
>> on tkinter, which is in turn a thin layer on top of Tcl/Tk. And Tcl/Tk
>> provides the GUI layer.
>> (See https://docs.python.org/3/library/tk.html.)
>>
>> I'm suggest that sometimes it may be better to use HTML5 to provide the
>> GUI layer. I pointed to Elm, to show how powerful HTML5 has become.
>>
>
> BeeWare uses Toga (a widget toolkit) and Briefcase (a build tool) to build
> native GUIs and SPA web apps
>
> > Write your apps in Python and release them on iOS, Android, Windows,
> MacOS, Linux, Web, and tvOS using rich, native user interfaces. One
> codebase. Multiple apps.
>
> Briefcase can build Django apps.
>
> https://pybee.org
> https://pybee.org/project/using/
> https://briefcase.readthedocs.io/en/latest/tutorial/tutorial-0.html
> https://toga.readthedocs.io/en/latest/tutorial/tutorial-0.html
>
> It's definitely not a single file module, though.
>
> Bottle is a single file web framework ('microframework'); but it doesn't
> have a widget toolkit.
>
> Web development is not as easy to learn as a simple GUI api for beginners
> (and then learning what to avoid in terms of websec is a lot to learn).
>
> There was a thread about deprecating Tk awhile back. There also I think I
> mentioned that asyncio event loop support would be great for real world
> apps.
>
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