I can't get the time difference between two transactions with kivy - python-3.x

Question

I want to keep the value returned from 2 time.time () methods in the on_event and on_leave functions in the ReflexScreen class. I want to use these values in the MainScreen class, but when I call these functions in the MainScreen class, these functions are called again and they do not keep the current value. So it returns me a new value and the value of both is the same because I called both at the same time.
from kivy.lang import Builder
from kivy.core.window import Window
from kivy.uix.screenmanager import Screen
from kivymd.app import MDApp
from time import sleep, time
from random import randint
from kivymd.uix.label import MDLabel
Window.size = (300, 500)
helper = """
ScreenManager:
MenuScreen:
ReflexScreen:
MainScreen:
<MainScreen>:
id: main
name: 'main'
BoxLayout:
orientation: 'vertical'
MDToolbar:
title: 'Test Your Reflex'
elevation:10
Widget:
MDRectangleFlatButton:
text: 'P L A Y'
on_press: root.manager.current = 'menu'
size_hint_x: None
size_hint_y: None
width: 20
height: 30
pos_hint: {'center_x':0.5, 'center_y':0.5}
md_bg_color: 0.2,0.3,0.6,0.1
text_color: 0.2, 0.5, 0.6, 1
MDLabel:
id: score_label
size_hint_x: 0.45
size_hint_y: None
pos_hint: {'center_x':0.5, 'center_y':0.4}
<ReflexScreen>:
id: reflex
name: 'reflex'
Button:
id: reflex_button
text: 'Wait Change The Color'
font_size: '20sp'
pos_hint: {'center_x':0.5, 'center_y':0.5}
on_press: root.manager.current = 'main'
size_hint_x: None
size_hint_y: None
width: 300
height: 500
background_color: 1,0,0,0.8
<MenuScreen>
id: menu
name: 'menu'
BoxLayout:
orientation: 'vertical'
MDToolbar:
title: 'Test Your Reflex'
elevation:10
Widget:
MDRectangleFlatButton:
text: 'P L A Y'
on_press: root.manager.current = 'reflex'
size_hint_x: None
size_hint_y: None
width: 20
height: 30
pos_hint: {'center_x':0.5, 'center_y':0.5}
md_bg_color: 0.2,0.3,0.6,0.1
text_color: 0.2, 0.5, 0.6, 1
"""
class ReflexScreen(Screen):
def on_enter(self, *args):
"""Event fired when the screen is displayed: the entering animation is
complete."""
sleep(randint(1,6))
self.ids.reflex_button.background_color = (0,1,0,0.8)
start = time()
print(start)
self.ids.reflex_button.text = 'CLICK !!!'
return start
def on_leave(self, *args):
end = time()
print(end)
self.ids.reflex_button.background_color = (1,0,0,0.8)
return end
"""rscreen = ReflexScreen()
start = rscreen.on_enter()
end = rscreen.on_leave()"""
class MainScreen(Screen):
def on_enter(self, *args):
rscreen = ReflexScreen()
start = rscreen.on_enter()
end = rscreen.on_leave()
#reflexclass = ReflexScreen()
#final_time = reflexclass.on_leave()-reflexclass.on_enter()
#print(final_time)
final_time = (end-start)
self.ids.score_label.text = f"TIME : {str(final_time)}"
If I add the code block below between two classes and use these variables in the MainScreen class,
rscreen = ReflexScreen()
start = rscreen.on_enter()
end = rscreen.on_leave()
I can get the result I want, but if I do this, kivy will tell me self.ids.reflex_button.background_color = (0,1,0,0.8) File "kivy \ properties.pyx", line 863, in kivy.properties.ObservableDict .__ getattr__ AttributeError: 'super' object has no attribute returns '__getattr__' error.
I think the reason for this is because of this. When the window is first loaded, the name value defined in the helper is not assigned, that name value is defined for the class when the window is opened for the second time. By doing a print (self), I see that the name value returns empty the first time and full the second time. How can I solve this problem or get the time difference between clicks?

Answer 1

The on_enter() and on_leave() methods are called for you. You do not need to explicitly call them yourself. You also do not need to do:
rscreen = ReflexScreen()
The ReflexScreen in your GUI is created when you load your helper string. and rscreen above is not the instance that appears in your GUI.
You can get the time difference by saving the start and end time in the ReflexScreen class, and adding a method to get the time difference:
class ReflexScreen(Screen):
start = NumericProperty()
end = NumericProperty()
def on_enter(self, *args):
"""Event fired when the screen is displayed: the entering animation is
complete."""
sleep(randint(1,6))
self.ids.reflex_button.background_color = (0,1,0,0.8)
self.start = time()
print(self.start)
self.ids.reflex_button.text = 'CLICK !!!'
# return start
def on_leave(self, *args):
self.end = time()
print(self.end)
self.ids.reflex_button.background_color = (1,0,0,0.8)
# set the text of a Label in MainScreen to show time difference
self.manager.get_screen('main').ids.score_label.text = str(self.end - self.start)
# return end
# a method to get the time difference
def get_time_diff(self):
return self.end - self.start
Haven't tested this code, so there may be some errors.