Help with kivy (error: Attributeerror: 'weakref' Object has no attribute 'cline_in_traceback')

Question

I’m learning the kivy (so I’m pretty virgin in the Gui subject) and I came across this mistake:

important part: Attributeerror: 'weakref' Object has no attribute 'cline_in_traceback'

full run:

[INFO   ] [Logger      ] Record log in /home/albuquerque/.kivy/logs/kivy_19-04-21_53.txt
[INFO   ] [Kivy        ] v1.11.0.dev0, git-eec3a30, 20190421
[INFO   ] [Python      ] v3.6.7 (default, Oct 22 2018, 11:32:17) 
[GCC 8.2.0]
[INFO   ] [Factory     ] 184 symbols loaded
[INFO   ] [Image       ] Providers: img_tex, img_dds, img_sdl2, img_pil, img_gif (img_ffpyplayer ignored)
[INFO   ] [Text        ] Provider: sdl2
[INFO   ] [Window      ] Provider: sdl2(['window_egl_rpi'] ignored)
[INFO   ] [GL          ] Using the "OpenGL" graphics system
[INFO   ] [GL          ] Backend used <sdl2>
[INFO   ] [GL          ] OpenGL version <b'4.6.0 NVIDIA 390.116'>
[INFO   ] [GL          ] OpenGL vendor <b'NVIDIA Corporation'>
[INFO   ] [GL          ] OpenGL renderer <b'GeForce GT 730M/PCIe/SSE2'>
[INFO   ] [GL          ] OpenGL parsed version: 4, 6
[INFO   ] [GL          ] Shading version <b'4.60 NVIDIA'>
[INFO   ] [GL          ] Texture max size <16384>
[INFO   ] [GL          ] Texture max units <32>
[INFO   ] [Window      ] auto add sdl2 input provider
[INFO   ] [Window      ] virtual keyboard not allowed, single mode, not docked
 Traceback (most recent call last):
   File "kivy/properties.pyx", line 840, in kivy.properties.ObservableDict.__getattr__
 KeyError: 'box'

 During handling of the above exception, another exception occurred:

 Traceback (most recent call last):
   File "main.py", line 19, in <module>
     Test().run()#O método run() inicializa o app
   File "/home/albuquerque/.local/lib/python3.6/site-packages/kivy/app.py", line 829, in run
     root = self.build()
   File "main.py", line 16, in build
     return Tarefas(["a","b", "c"])
   File "main.py", line 10, in __init__
     self.ids.box.add_widget(Label(text=tarefa, font_size=30))#procura nos ids da classe no arquivo text.kv o id box
   File "kivy/properties.pyx", line 843, in kivy.properties.ObservableDict.__getattr__
 AttributeError: 'super' object has no attribute '__getattr__'
Exception ignored in: functools.partial(<function _widget_destructor at 0x7f5c199612f0>, 3)
Traceback (most recent call last):
  File "/home/albuquerque/.local/lib/python3.6/site-packages/kivy/uix/widget.py", line 265, in _widget_destructor
  File "/home/albuquerque/.local/lib/python3.6/site-packages/kivy/lang/builder.py", line 760, in unbind_widget
  File "kivy/weakproxy.pyx", line 32, in kivy.weakproxy.WeakProxy.__getat

the interface screen does not even open

below are the codes:

main py.

from kivy.app import * #importar os métodos de APPP do kivy
from kivy.uix.boxlayout import BoxLayout #empilha os widgets como se fossem caixas
from kivy.uix.label import Label
from kivy.uix.scrollview import ScrollView

class Tarefas(ScrollView):
    def __init__(self, tarefas, **kwargs): #keyword arguments, o incrivel é que ele executa os argumentos colocados a mais
        super().__init__(**kwargs)#chama as funções da classe BoxLayout
        for tarefa in tarefas:
            self.ids.box.add_widget(Label(text=tarefa, font_size=30))#procura nos ids da classe no arquivo text.kv o id box


class Test(App):#primeiro arquivo que o kivy procura (no caso, Text.kv)

    def build(self): #Métod o que constroi o aplicativo
        return Tarefas(["a","b", "c"])


Test().run()#O método run() inicializa o app

test.Kv

<Tarefas>:
    BoxLayout:
        id:box #identificação do widget
        orientation:"vertical"
        size_hint_y:None
        height:self.minimum_height

I’m kind of desperate, so if you can help me, I’m desperately grateful :D:

Answer 1

You need to import the Kv file.

from kivy.lang import Builder

Builder.load_file('test.kv')