Fix bug, when user canceled filechooser, on_selection does not dispatched

[Neizvestnyj]

When clicking the close button, on OS X on_selection was not called

from textwrap import dedent

from plyer import filechooser

from kivy.app import App
from kivy.lang import Builder
from kivy.properties import ListProperty
from kivy.uix.button import Button


class FileChoose(Button):
    '''
    Button that triggers 'filechooser.open_file()' and processes
    the data response from filechooser Activity.
    '''

    selection = ListProperty([])

    def choose(self):
        '''
        Call plyer filechooser API to run a filechooser Activity.
        '''
        filechooser.open_file(on_selection=self.handle_selection)

    def handle_selection(self, selection):
        '''
        Callback function for handling the selection response from Activity.
        '''
        self.selection = selection

    def on_selection(self, *a, **k):
        '''
        Update TextInput.text after FileChoose.selection is changed
        via FileChoose.handle_selection.
        '''
        print(self.selection)
        App.get_running_app().root.ids.result.text = str(self.selection)


class ChooserApp(App):
    '''
    Application class with root built in KV.
    '''

    def build(self):
        return Builder.load_string(dedent('''
            <FileChoose>:
            BoxLayout:
                BoxLayout:
                    orientation: 'vertical'
                    TextInput:
                        id: result
                        text: ''
                        hint_text: 'selected path'
                    FileChoose:
                        size_hint_y: 0.1
                        on_release: self.choose()
                        text: 'Select a file'
        ''')
                                   )


if __name__ == '__main__':
    ChooserApp().run()

Demo.mp4

[tshirtman]

But, you didn't select anything, why should it be called?

[Neizvestnyj]

But, you didn't select anything, why should it be called?

Because on others platform (win/linux) its called and if the user clicked the close button there is no way to find out it

[HyTurtle]

Does setting allownone and/or force_dispatch to True on you ListProperty not do the same? And without the issue created of defaulting to a True/Truthy value

[Neizvestnyj]

Does setting allownone and/or force_dispatch to True on you ListProperty not do the same? And without the issue created of defaulting to a True/Truthy value

No, selection = ListProperty(['']) / selection = ListProperty([True]) does not work

[tshirtman]

Doesn't seem to be the case on Linux? (i just tested and if i close the selection window, there is no change)
https://github.com/kivy/plyer/blob/master/plyer/platforms/linux/filechooser.py#L68
but on Windows indeed seems to be the case
https://github.com/kivy/plyer/blob/master/plyer/platforms/win/filechooser.py#L149
although it returns [] not [''].
on android, it seems it would dispatch [] as well.
https://github.com/kivy/plyer/blob/master/plyer/platforms/android/filechooser.py#L194
not sure on ios
https://github.com/kivy/plyer/blob/master/plyer/platforms/ios/filechooser.py#L77

[Neizvestnyj]

Doesn't seem to be the case on Linux? (i just tested and if i close the selection window, there is no change) https://github.com/kivy/plyer/blob/master/plyer/platforms/linux/filechooser.py#L68 but on Windows indeed seems to be the case https://github.com/kivy/plyer/blob/master/plyer/platforms/win/filechooser.py#L149 although it returns [] not ['']. on android, it seems it would dispatch [] as well. https://github.com/kivy/plyer/blob/master/plyer/platforms/android/filechooser.py#L194 not sure on ios https://github.com/kivy/plyer/blob/master/plyer/platforms/ios/filechooser.py#L77

Yes, on different platforms different return...

[HyTurtle]

Does setting allownone and/or force_dispatch to True on you ListProperty not do the same? And without the issue created of defaulting to a True/Truthy value

No, selection = ListProperty(['']) / selection = ListProperty([True]) does not work

that would be selection = ListProperty([], allownone=True, force_dispatch=True)

[Neizvestnyj]

@tshirtman I can change in commit selection = [''] to selection = [], but in example code I need to set selection = List Property([''])

[Neizvestnyj]

selection = ListProperty([], allownone=True, force_dispatch=True)

does not work

[HyTurtle]

Could adjust your commit so it passes None to _handle_selection - that shouldn't break how it currently operates.

[Neizvestnyj]

selection = None

if panel.runModal():
    if self.mode == "save" or not self.multiple:
        selection = [panel.filename().UTF8String()]
    else:
        filename = panel.filenames()
        selection = [
            filename.objectAtIndex_(x).UTF8String()
            for x in range(filename.count())]

self._handle_selection(selection)

return selection

# in app
selection = ListProperty([], allownone=True)

so?

[HyTurtle]

Seems harmless to me, does that selection trigger / not trigger or error without the allownone. and _handle_selection is a dummy method so in app you can redefine that if need be.

[Neizvestnyj]

Seems harmless to me, does that selection trigger / not trigger or error without the allownone. and _handle_selection is a dummy method so in app you can redefine that if need be.

Thanks, done

[HyTurtle]

Just tried to read the relevant docs here, mind testing print(panel.runModal()) with a selection made and an exit; won't matter too much just curious if the exit/cancel is just 0.

[Neizvestnyj]

Just tried to read the relevant docs here, mind testing print(panel.runModal()) with a selection made and an exit; won't matter too much just curious if the exit/cancel is just 0.

hmm, yes, I see

[tshirtman]

LGTM

please fix the style issue though, (line > 80 breaks pep8)

[Neizvestnyj]

LGTM

please fix the style issue though, (line > 80 breaks pep8)

Ah, yes, I see, fixed it)