Right way to add a widget to an instance imported from kv file

[Juan Francisco López-Egea Martínez]

Hi, I'm trying to add a widget (button) to a GridLayout instance imported from Kv file, but find no way. I read in stackoverflow something about clock and lambdas, but still no lucky, so, I'm gonna ask it here, take a look just at "for" loop (the other things, label, color change, etc... neverminds). I must to say in Kv file there are some buttons added "at hand" (or hardcoded), i would like to be able to add/remove a widget from being parented to another on the fly.

Well, the code:

main.py:

from kivy.app import App
from kivy.uix.widget import Widget
from kivy.uix.button import Button
from kivy.properties import NumericProperty, ReferenceListProperty, ObjectProperty
from kivy.clock import Clock
from colorsys import hsv_to_rgb, rgb_to_hsv
from kivy.uix.gridlayout import GridLayout
#from kivy.uix.scrollview import ScrollView

#class Sview(ScrollView):
#    scrollviewClass = ObjectProperty(None)

#class Glayout(GridLayout):
#    gridLayoutClass = ObjectProperty(None)

class MoneyControl(Widget):
    cartel = ObjectProperty(None)
    mainScrollView = ObjectProperty(None)
    childGridLayout = ObjectProperty(None)

    lay = 3
    rainbow = [0.0,1.0,1.0,1.0]

    buttonsList = [None]
    for i in range(100):
        #ANY OF THIS WAYS TO ADD A WIDGET WORKS. WHICH ONE WOULD BE THE RIGHT ONE?
        self.childGridLayout.add_widget(Button(text="This now works?")) #Opt1
        #childGridLayout.add_widget(Button(text="This now works?")) #Opt2
        #Clock.schedule_once(lambda dt: childGridLayout.add_widget(TbuttonOdd)) #Opt3
        #Clock.schedule_once(lambda dt: self.childGridLayout.add_widget(TbuttonOdd)) #Opt4
        #GridLayout(childGridLayout).add_widget(TbuttonOdd) #Opt5
    print buttonsList

    def hsva_to_rgba(self, hsva):
        rgba = hsv_to_rgb(hsva[0], hsva[1], hsva[2])
        rgba = list(rgba)
        rgba.append(hsva[3])
        return rgba

    def update(self, dt):
        self.lay += 1
        self.cartel.text = str(self.lay)
        #self.cartel.colormode = hsv
        #self.cartel.color = self.lay*0.0001, self.lay*0.0002, self.lay*0.0004, 1
        self.rainbow[0] += self.lay*0.0001
        finalRgba = self.hsva_to_rgba(self.rainbow)
        self.cartel.color = finalRgba


class MoneyControlApp(App):
    def build(self):
        prog = MoneyControl()
        Clock.schedule_interval(prog.update, 1.0 / 60.0)
        return prog

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

kv file:

#:kivy 1.0.9

<TbuttonEven@Button>:# nameYouWant @ class
    text: "Test Text"
    size_hint_y: None
    height: 40
    background_normal: ""
    background_color: 0.7, 0.9, 0.7, 1.0

<TbuttonOdd@Button>:# nameYouWant @ class
    text: "Different BgColor!"
    size_hint_y: None
    height: 40
    background_normal: ""
    background_color: 0.6, 0.85, 0.6, 1.0

<ScView@ScrollView>:
    size_hint: None, None
    #size: root.width, root.height
    #top: 0
    #center_x: root.width
    pos: 100,200

<Glo@GridLayout>:
    cols:1
    spacing:0
    size_hint: None, None
    #size_hint_x: None #False en lugar de None?
    #size_hint_y: None #False en lugar de None?
    height: self.minimum_height

<MoneyControl@Widget>:
#MoneyControl:#RootWidget
    cartel: crt
    mainScrollView:rollerresults
    childGridLayout:resultsBlock

    ScView:
        id:rollerresults
        size: 800, 600

        Glo:
            id:resultsBlock

            TbuttonOdd:
            TbuttonEven:
            TbuttonOdd:
            TbuttonEven:
            TbuttonOdd:
            TbuttonEven:
            TbuttonOdd:
            TbuttonEven:
            TbuttonOdd:
            TbuttonEven:
            TbuttonOdd:
            TbuttonEven:
            TbuttonOdd:
            TbuttonEven:
            TbuttonOdd:
            TbuttonEven:
            TbuttonOdd:
            TbuttonEven:
            TbuttonOdd:
            TbuttonEven:
            TbuttonOdd:
            TbuttonEven:
            TbuttonOdd:
            TbuttonEven:
            TbuttonOdd:
            TbuttonEven:
            TbuttonOdd:
            TbuttonEven:
            TbuttonOdd:
            TbuttonEven:
            TbuttonOdd:
            TbuttonEven:
            TbuttonOdd:
            TbuttonEven:
            TbuttonOdd:
            TbuttonEven:
            TbuttonOdd:

    Label:
        id: crt
        font_size: 20
        center_x: root.width * 0.5
        top: root.height * 0.5
        text: "hola"
        color: 1, .3, .8, 1

Whats the right way to access the functions of a... layout instance? I can access and modify Label instance properties, but not the gridLayout ones!...

[ZenCODE]

This line is correct.

self.childGridLayout.add_widget(Button(text="This now works?")) #Opt1

But your kv rule does not make sense. Glo?

        Glo:
            id:resultsBlock




Surely that should be "GridLayout:"?


[Juan Francisco López-Egea Martínez]

Glo is an instance of the class Glo (GridLayOut) defined a little bit more up, and an id to that instance, to be able to add buttons later.

Is that way a wrong way to do it?.

Thank you for your time and support ZenCODE.

[ZenCODE]

No, that is fine. I missed that. But then surely

    self.childGridLayout.add_widget(Button(text="This now works?")) #Opt1

works, as the comment indicates? So what exactly is the problem?

[Juan Francisco López-Egea Martínez]

It says to me:

NameError: name 'self' is not defined.

Thing that drives me crazy, since self.cartel for example works wonderfully to be able to modify text and color...

I'm using Kivy v1.9.0
Is a matter of use Kivy master version?

[ZenCODE]

Yes, you have put that code in the class definition, not in any method. Try

class MoneyControl(Widget):
    cartel = ObjectProperty(None)
    mainScrollView = ObjectProperty(None)
    childGridLayout = ObjectProperty(None)

    lay = 3
    rainbow = [0.0,1.0,1.0,1.0]

    def __init__(self, **kwargs):

        buttonsList = [None]
        for i in range(100):
            #ANY OF THIS WAYS TO ADD A WIDGET WORKS. WHICH ONE WOULD BE THE RIGHT ONE?

[Juan Francisco López-Egea Martínez]

Done. But still same error as at beginning: AttributeError: 'NoneType' object has no attribute 'add_widget'

main.py:

from kivy.app import App
from kivy.uix.widget import Widget
from kivy.uix.button import Button
from kivy.properties import NumericProperty, ReferenceListProperty, ObjectProperty
from kivy.clock import Clock
from colorsys import hsv_to_rgb, rgb_to_hsv
from kivy.uix.gridlayout import GridLayout
#from kivy.uix.scrollview import ScrollView

#class Sview(ScrollView):
#    scrollviewClass = ObjectProperty(None)

#class Glayout(GridLayout):
#    gridLayoutClass = ObjectProperty(None)

class MoneyControl(Widget):
    cartel = ObjectProperty(None)
    mainScrollView = ObjectProperty(None)
    childGridLayout = ObjectProperty(None)
    lay = 3
    rainbow = [0.0,1.0,1.0,1.0]

    def __init__(self, **kwargs):
        buttonsList = [None]
        for i in range(100):

            self.childGridLayout.add_widget(Button(text="This now works?")) #Opt1

#    print buttonsList

    def hsva_to_rgba(self, hsva):
        rgba = hsv_to_rgb(hsva[0], hsva[1], hsva[2])
        rgba = list(rgba)
        rgba.append(hsva[3])
        return rgba

    def update(self, dt):
        self.lay += 1
        self.cartel.text = str(self.lay)
        #self.cartel.colormode = hsv
        #self.cartel.color = self.lay*0.0001, self.lay*0.0002, self.lay*0.0004, 1
        self.rainbow[0] += self.lay*0.0001
        finalRgba = self.hsva_to_rgba(self.rainbow)
        self.cartel.color = finalRgba


class MoneyControlApp(App):
    def build(self):
        prog = MoneyControl()
        Clock.schedule_interval(prog.update, 1.0 / 60.0)
        return prog

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

I'm starting to ask myself if there is something terribly bad on my machine or what is happening...