KivyMD Screen Manager, cannot get working - python-3.x

Question

I am referring to this video and trying to replicate the same using KivyMD. Basically it is a simple app with the screen manager. Once you enter the password pswd it takes you to the next screen and on the release of the button, it comes back.
I am trying to replace the text filed with KivyMD TestRoundField
main.py file from the Tutorial
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen
class MainWindow(Screen):
pass
class SecondWindow(Screen):
pass
class WindowManager(ScreenManager):
pass
kv = Builder.load_file("my.kv")
class MyMainApp(App):
def build(self):
return kv
if __name__ == "__main__":
MyMainApp().run()
my.kv file from the tutorial - Password - pswd
WindowManager:
MainWindow:
SecondWindow:
<MainWindow>:
name: "main"
GridLayout:
cols:1
GridLayout:
cols:2
Label:
text: "Password"
TextInput:
id: passw
multiline: False
Button:
text: "Submit"
on_release:
app.root.current = "second" if passw.text == "pswd" else "main"
root.manager.transition.direction = "left"
<SecondWindow>:
name: "second"
Button:
text: "Go Back"
on_release:
app.root.current = "main"
root.manager.transition.direction = "right"
My Code
This is my main.py file -
from kivy.factory import Factory
from kivymd.app import MDApp
from kivy.lang import Builder
kivyFile = Builder.load_file("loginKivy.kv")
class MainApp(MDApp):
def __init__(self, **kwargs):
self.title = "KivyMD Examples - Round Text Field"
self.theme_cls.primary_palette = "BlueGray"
super().__init__(**kwargs)
def build(self):
self.root = Factory.Password()
return kivyFile
class Second_Screen(Screen):
pass
if __name__ == "__main__":
MainApp().run()
This is my loginKivy.kv file
#:set color_shadow [0, 0, 0, .2980392156862745]
#:set color_lilac [.07058823529411765, .07058823529411765, .14901960784313725, .8]
<MyMDTextFieldRound#MDTextFieldRound>
size_hint_x: None
normal_color: color_shadow
active_color: color_shadow
pos_hint: {"center_x": .5}
<Password#Screen>
canvas:
Color:
rgba: color_lilac
Rectangle:
pos: self.pos
size: self.size
BoxLayout:
orientation: "vertical"
size_hint_y: None
height: self.minimum_height
spacing: dp(15)
pos_hint: {"center_x": .5, "center_y": .5}
MyMDTextFieldRound:
icon_type: "without"
hint_text: "Field without icon"
color: 1,0,1,1
I am confused on how to proceed further. What should I do next?

Answer 1

I suggest changing your build() method to:
def build(self):
return Builder.load_file("loginKivy.kv")
# sm = ScreenManager()
# sm.add_widget(Factory.Password())
# sm.add_widget(Second_Screen())
# return sm
Then you need to add the "Submit" and "Go Back" Buttons to your kv as well as the <Second_Screen> rule.
You can add those Buttons using kivy Button or kivyMD MDRaisedButton:
#:set color_shadow [0, 0, 0, .2980392156862745]
#:set color_lilac [.07058823529411765, .07058823529411765, .14901960784313725, .8]
ScreenManager:
Password:
Second_Screen:
<MyMDTextFieldRound#MDTextFieldRound>
size_hint_x: None
normal_color: color_shadow
active_color: color_shadow
pos_hint: {"center_x": .5}
<Password#Screen>
name: "main"
canvas:
Color:
rgba: color_lilac
Rectangle:
pos: self.pos
size: self.size
BoxLayout:
orientation: "vertical"
size_hint_y: None
height: self.minimum_height
spacing: dp(15)
pos_hint: {"center_x": .5, "center_y": .5}
MyMDTextFieldRound:
id: passw
icon_type: "without"
hint_text: "Field without icon"
color: 1,0,1,1
MDRaisedButton:
text: "Submit"
pos_hint: {'center_x': 0.5}
on_release:
app.root.current = "second" if passw.text == "pswd" else "main"
root.manager.transition.direction = "left"
<Second_Screen>:
name: 'second'
MDRaisedButton:
text: "Go Back"
pos_hint: {'center_x': 0.5, 'center_y': 0.5}
on_release:
app.root.current = "main"
root.manager.transition.direction = "right"
I have also added the ScreenManager structure allowing the build() method to just return the result of loading the kv file.
The documentation for kv can be found at kivy.lang