I would like to import optional GUI elements defined in separate .py files and add/remove these dynamically from the main GUI. The optional elements are defined in a text configuration file and thus the file names are not known in advance. My original idea was to impose a common format - the main class would be identically named in all module files. I found that the simplest implementation of this behaves in an unexpected way. Although the imported objects appear to have distinct names, there is in fact cross-talk. This demonstrates the issue and a workaround that I found on SE (commented out):
from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.button import Button
from kivy.lang import Builder
import importlib
Builder.load_string('''
<MainWidget>:
orientation: 'vertical'
BoxLayout:
Button:
text: "Load Mod 1"
on_press:
root.load_module(self.text)
Button:
text: "Load Mod 2"
on_press:
root.load_module(self.text)
Button:
text: "Unload all"
on_press:
dock.clear_widgets()
FloatLayout:
id: dock
''')
class MainWidget(BoxLayout):
def load_module(self, hint):
self.ids.dock.clear_widgets()
if "1" in hint:
self.module = importlib.import_module("Mod1").Module()#PROBLEMATIC
#module = importlib.import_module("Mod1")
#class_ = getattr(module, "Module1")
#self.module = class_()
if "2" in hint:
self.module = importlib.import_module("Mod2").Module()#PROBLEMATIC
#module = importlib.import_module("Mod2")
#class_ = getattr(module, "Module2")
#self.module = class_()
self.ids.dock.add_widget(self.module)
class MyApp(App):
def build(self):
return MainWidget()
if __name__ == '__main__':
MyApp().run()
Mod1.py:
from kivy.uix.floatlayout import FloatLayout
from kivy.lang import Builder
Builder.load_string('''
#<Module1>:
<Module>: #PROBLEMATIC
size_hint: None, None
size: self.parent.size if self.parent else self.size
pos: self.parent.pos if self.parent else self.pos
Button:
size_hint: None, None
width: self.parent.width / 3
height: self.parent.height
pos: self.parent.pos
text: "Mod 1"
on_press: print(root); print([x for x in dir(root) if 'method' in str(x)])
''')
#class Module1(FloatLayout):
class Module(FloatLayout): #PROBLEMATIC
def __init__(self, **kwargs):
super(FloatLayout, self).__init__(**kwargs)
def dummymethod1(self):
pass
Mod2.py:
from kivy.uix.floatlayout import FloatLayout
from kivy.lang import Builder
Builder.load_string('''
#<Module2>:
<Module>: #PROBLEMATIC
size_hint: None, None
size: self.parent.size if self.parent else self.size
pos: self.parent.pos if self.parent else self.pos
Button:
size_hint: None, None
width: self.parent.width / 3
height: self.parent.height
pos: (self.parent.x + self.parent.width / 2) , self.parent.y
text: "Mod 2"
on_press: print(root); print([x for x in dir(root) if 'method' in str(x)])
''')
#class Module2(FloatLayout):
class Module(FloatLayout): #PROBLEMATIC
def __init__(self, **kwargs):
super(FloatLayout, self).__init__(**kwargs)
def dummymethod2(self):
pass
It appears that although the modules have distinct names Mod1 and Mod2, the main class having the same name is a problem. Once both modules have been imported at least once, both appear in the GUI regardless which one is actually activated.
Although my workaround works to prevent this unwanted behaviour, I would like to know what causes it. Is this to do with how importing works in Python in general, or a Kivy specific issue? Is there another way to deal with this that would allow for identically-names classes in otherwise distinct modules?
I would like to import optional GUI elements defined in separate .py files and add/remove these dynamically from the main GUI. The optional elements are defined in a text configuration file and thus the file names are not known in advance. My original idea was to impose a common format - the main class would be identically named in all module files. I found that the simplest implementation of this behaves in an unexpected way. Although the imported objects appear to have distinct names, there is in fact cross-talk. This demonstrates the issue and a workaround that I found on SE (commented out):
from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.button import Button
from kivy.lang import Builder
import importlib
Builder.load_string('''
<MainWidget>:
orientation: 'vertical'
BoxLayout:
Button:
text: "Load Mod 1"
on_press:
root.load_module(self.text)
Button:
text: "Load Mod 2"
on_press:
root.load_module(self.text)
Button:
text: "Unload all"
on_press:
dock.clear_widgets()
FloatLayout:
id: dock
''')
class MainWidget(BoxLayout):
def load_module(self, hint):
self.ids.dock.clear_widgets()
if "1" in hint:
self.module = importlib.import_module("Mod1").Module()#PROBLEMATIC
#module = importlib.import_module("Mod1")
#class_ = getattr(module, "Module1")
#self.module = class_()
if "2" in hint:
self.module = importlib.import_module("Mod2").Module()#PROBLEMATIC
#module = importlib.import_module("Mod2")
#class_ = getattr(module, "Module2")
#self.module = class_()
self.ids.dock.add_widget(self.module)
class MyApp(App):
def build(self):
return MainWidget()
if __name__ == '__main__':
MyApp().run()
Mod1.py:
from kivy.uix.floatlayout import FloatLayout
from kivy.lang import Builder
Builder.load_string('''
#<Module1>:
<Module>: #PROBLEMATIC
size_hint: None, None
size: self.parent.size if self.parent else self.size
pos: self.parent.pos if self.parent else self.pos
Button:
size_hint: None, None
width: self.parent.width / 3
height: self.parent.height
pos: self.parent.pos
text: "Mod 1"
on_press: print(root); print([x for x in dir(root) if 'method' in str(x)])
''')
#class Module1(FloatLayout):
class Module(FloatLayout): #PROBLEMATIC
def __init__(self, **kwargs):
super(FloatLayout, self).__init__(**kwargs)
def dummymethod1(self):
pass
Mod2.py:
from kivy.uix.floatlayout import FloatLayout
from kivy.lang import Builder
Builder.load_string('''
#<Module2>:
<Module>: #PROBLEMATIC
size_hint: None, None
size: self.parent.size if self.parent else self.size
pos: self.parent.pos if self.parent else self.pos
Button:
size_hint: None, None
width: self.parent.width / 3
height: self.parent.height
pos: (self.parent.x + self.parent.width / 2) , self.parent.y
text: "Mod 2"
on_press: print(root); print([x for x in dir(root) if 'method' in str(x)])
''')
#class Module2(FloatLayout):
class Module(FloatLayout): #PROBLEMATIC
def __init__(self, **kwargs):
super(FloatLayout, self).__init__(**kwargs)
def dummymethod2(self):
pass
It appears that although the modules have distinct names Mod1 and Mod2, the main class having the same name is a problem. Once both modules have been imported at least once, both appear in the GUI regardless which one is actually activated.
Although my workaround works to prevent this unwanted behaviour, I would like to know what causes it. Is this to do with how importing works in Python in general, or a Kivy specific issue? Is there another way to deal with this that would allow for identically-names classes in otherwise distinct modules?
Share Improve this question asked Apr 1 at 21:48 Eugene BEugene B 617 bronze badges1 Answer
Reset to default 1I think the problem is on your kv strings. Each time you import Mod1 or Mod2, their respective kv strings are loaded. When a rule is loaded for a class (such as <module>), that rule is saved in Builder. If another rule is then loaded for the same class name, it overrides the previously loaded rule. If you press either Button in the loaded Module, it will display the info for the most recently loaded module. There may be other issues associated with loading kv strings multiple times.
I would suggest removing the kv strings from the modules and add a rule for <Module> in the main python script so that it only gets loaded once, like this:
<Module>:
Button:
size_hint: None, None
width: self.parent.width / 3
height: self.parent.height
pos: self.parent.pos
text: str(root)[1:].split('.')[0]
on_press: print(root); print([x for x in dir(root) if 'method' in str(x)])
I also changed:
FloatLayout:
id: dock
to:
BoxLayout:
id: dock
and removed the line:
self.ids.dock.clear_widgets()
from the load_module() method.