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Python Kivy Dyanmic Class not defined

I keep getting a Name Error reporting "name TripButton is not defined" although I have a button called TripButton defined in the same .kv file.
#:kivy 1.11.1
<TripButton#Button>:
size_hint: (0.15,0.15)
pos_hint: {'y':0.84}
text:"Test Text"
<MyPopup>:
size_hint: 0.5, 0.5
auto_dismiss: False
title: 'New Trip'
BoxLayout:
orientation: 'vertical'
TextInput:
id: trip_name
multiline: False
BoxLayout:
size_hint_y: None
height: 30
Button:
text: 'Submit'
on_release:
root.parent.parent.add_widget(TripButton(text=trip_name.text, size_hint=(1,0.1)))
root.dismiss()
Button:
text: 'Cancel'
on_release: root.dismiss()
<FirstScreen>:
name: 'first'
FloatLayout:
BoxLayout:
size_hint: (0.95, 0.95)
pos_hint: {'center_x':0.5, 'center_y':0.5}
orientation: "vertical"
canvas.before:
Color:
rgba: (1, 0, 0, 1) # Red color
Rectangle:
pos: self.pos
size: self.size
BoxLayout:
TripButton:
Button:
text: 'Add Trip'
font_size: 12
size_hint: (0.1, 0.1)
pos_hint: {'right':1, 'bottom':1}
on_release: app.open_popup()
pos_hint: {'right':1, 'bottom':1}
on_release: app.open_popup()
I tried declaring the TripButton class above and below the MyPopup class and that didn't work. I compared my code with the kivy documentation for dynamic classes and the from what I can tell I'm matching the syntax. I tried importing the Button class in both the python file and the .kv file and that hasn't worked.
To clarify all of this is in the same .kv file in the same directory as the python file. the app runs until I click the submit button in MyPopup then the program crashes and I get the NameError. This is what I have in my python file.
from kivy.app import App
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.uix.popup import Popup
class FirstScreen(Screen):
pass
class MyPopup(Popup):
pass
class MyApp(App):
def build(self):
sm = ScreenManager()
sm.add_widget(FirstScreen(name='first'))
sm.current = 'first'
return sm
def open_popup(self):
p = MyPopup()
p.open()
def add_button(self):
pass
if __name__ == '__main__':
MyApp().run()
What am I doing wrong? What else I can try? Thanks for your time.

To access classes defined within kv file use kivy.factory.Factory
Add id attribute to your button's BoxLayout, so replace following part of kv file:
BoxLayout:
TripButton:
with
BoxLayout:
id: trip_buttons
TripButton:
then replace:
root.parent.parent.add_widget(TripButton(text=trip_name.text, size_hint=(1,0.1)))
with:
app.root.current_screen.ids.trip_buttons.add_widget(kivy.factory.Factory.TripButton(text=trip_name.text, size_hint=(1,0.1)))
You also duplicated following lines within last button definition on first screen. Replace:
pos_hint: {'right':1, 'bottom':1}
on_release: app.open_popup()
pos_hint: {'right':1, 'bottom':1}
on_release: app.open_popup()
with
pos_hint: {'right':1, 'bottom':1}
on_release: app.open_popup()

How to get the selected value from my kivy dropdown menu

I have a dropdown menu in which I would like to know which value the user has selected so I can use it later in my program. This is my .kv code:
BoxLayout:
orientation: 'horizontal'
size_hint_x: 1
Button:
pos_hint:{'center_x': .5, 'center_y': .5}
id: units_num_btn
text: '0'
size_hint_y: None
height: 44
on_parent: drop_player_numbers_units.dismiss()
on_release: drop_player_numbers_units.open(self)
DropDown:
id: drop_player_numbers_units
on_select: units_num_btn.text = '{}'.format(args[1])
on_select: app.return_player_numbers()
Button:
id: units_num_btn_1
text: '1'
size_hint_y: None
height: 35
on_release: drop_player_numbers_units.select('1')
Button:
id: units_num_btn_2
text: '2'
size_hint_y: None
height: 35
on_release: drop_player_numbers_units.select('2')
and so on.
My .py code is here:
class drop_content(DropDown):
pass
class PlayerScreen(Screen):
pass
class TheApp(App):
def build(self):
sm = ScreenManager()
sm.add_widget(PlayerScreen(name='player_setup'))
sm.current = 'player_setup'
return sm
def main():
Builder.load_file('menu.kv')
app = TheApp()
app.run()
if __name__ == '__main__':
main()
I have previously used a function such as this:
# .py example
def return_text(self):
text = self.root.get_screen('screen').ids.specific_id.text
print(text)
# .kv example
TextInput:
id: input
text: "2"
on_text: app.return_text()
which did return text using a Textinput type in my .kv file. I know it doesn't work for the dropdown menu since the text is not inputted in the same way. Do you know how I would do this?
Thanks in advance

from kivy.app import App
from kivy.uix.dropdown import DropDown
from kivy.uix.screenmanager import Screen,ScreenManager
from kivy.lang.builder import Builder
class TestScreen(Screen):
def return_player_numbers(self,play_number):
print('Test : ',play_number)
kv = '''
ScreenManager:
TestScreen:
<TestScreen>:
BoxLayout:
orientation: 'horizontal'
size_hint_x: 1
Button:
pos_hint:{'center_x': .5, 'center_y': .5}
id: units_num_btn
text: '0'
size_hint_y: None
height: 44
on_parent: drop_player_numbers_units.dismiss()
on_release: drop_player_numbers_units.open(self)
DropDown:
id: drop_player_numbers_units
on_select:
units_num_btn.text = '{}'.format(args[1])
app.root.current_screen.return_player_numbers(args[1])
app.return_player_numbers(args[1])
Button:
id: units_num_btn_1
text: '1'
size_hint_y: None
height: 35
on_release: drop_player_numbers_units.select('1')
Button:
id: units_num_btn_2
text: '2'
size_hint_y: None
height: 35
on_release: drop_player_numbers_units.select('2')
'''
class TheApp(App):
def return_player_numbers(self,play_number):
print('App : ',play_number)
def build(self):
return Builder.load_string(kv)
if __name__ == '__main__':
TheApp().run()

I have found a way that I think is simpler than the current answer provided. This method uses that fact that the text on the button used to initiate the drop down changes as another button is selected. This is to show the user what they have selected. Since I want to know the text the user has selected from the drop down menu, and this is in fact the same thing that is updated on the initial button, I can just read the text from the button to obtatin my result like so:
(in .kv file)
<player_setup>
BoxLayout:
orientation: 'horizontal'
size_hint_x: 0.2
pos_hint: {'x':.4, 'y':0}
Button:
pos_hint:{'center_x': .5, 'center_y': .5}
id: tens_num_btn
text: '0'
size_hint_y: None
# size_hint_x: 0.1
height: 44
on_parent: drop_player_numbers_tens.dismiss()
on_release: drop_player_numbers_tens.open(self)
DropDown:
id: drop_player_numbers_tens
on_select:
#######
tens_num_btn.text = '{}'.format(args[1])
# this line here ^ is the one that re-formats the text of the button above to
# the selected text
app.return_player_numbers()
max_height: 120
(.py file)
def return_player_numbers(self):
player_number = self.root.get_screen('player_setup').ids.tens_num_btn.text
return player_number
This also allows me to concatenate multiple dropdown results using a single function, however it is menu specific. In my case, this works better for me

Using Kivy, how do I have a checkbox's active (or inactive) status rotate (or not rotate) an image on the second screen?

On the first screen, I have a checkbox that asks the user if they want their image in landscape mode. On the second screen, my code currently uses a canvas and rotates the image 90 degrees. If that box is not checked, that means the user wants the image to be portrait mode, and I need that canvas to be cleared.
my.kv
WindowManager:
MainWindow:
SecondWindow:
<MainWindow>:
id: main_window
name: "main"
BoxLayout:
orientation: "vertical"
size: root.width, root.height
padding: 50
Label:
text: "Email"
color: 0,0,0,1
font_size: 32
BoxLayout:
orientation: "horizontal"
Label:
text: "Email Address:"
color: 0,0,0,1
TextInput:
size_hint_y: None
pos_hint: {'center_y': .5}
height: 38
multiline: True
padding: 10
BoxLayout:
orientation: "horizontal"
Label:
text: "Display Landscape Mode?"
color: 0,0,0,1
CheckBox:
id: checkbox_confirm_mode
on_active:
root.checkbox_click_mode(self, self.active)
pos_hint: {'center_x': .5}
BoxLayout:
orientation: "horizontal"
Label:
text: "Stretch image to fill screen?"
color: 0,0,0,1
CheckBox:
id: checkbox_confirm_stretch
on_active:
root.checkbox_click_stretch(self, self.active)
pos_hint: {'center_x': .5}
BoxLayout:
orientation: "horizontal"
Label:
text: "I double-checked that my email is typed correctly:"
color: 0,0,0,1
CheckBox:
id: checkbox_confirm_email
on_active:
root.checkbox_click(self, self.active)
root.disable_button()
pos_hint: {'center_x': .5}
BoxLayout
orientation: "vertical"
Button:
id:submit_button
text: "Submit"
disabled: True
size_hint: (0.2, None)
pos_hint: {'center_x': .5}
height: 50
on_release:
app.root.current = "second"
root.manager.transition.direction = "left"
<SecondWindow>:
id: second_window
name: "second"
canvas:
Rotate:
angle: 90
origin: self.center
Image:
source: 'Troy.png'
keep_ratio: True
allow_stretch: False
main.py
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.core.window import Window
from kivy.properties import ObjectProperty
from kivy.config import Config
Config.set('input', 'mouse', 'mouse,multitouch_on_demand')
class MainWindow(Screen):
def on_pre_enter(self):
Window.size = (750,400)
Window.clearcolor = (1, 1, 1, 1)
def checkbox_click(self, instance, value):
return value
def checkbox_click_mode(self, instance, value):
return value
def checkbox_click_stretch(self, instance, value):
return value
def clear_canvas(self):
self.canvas.clear()
return
def disable_button(self):
if self.ids.checkbox_confirm_email.active == False:
self.ids.submit_button.disabled = True
else:
self.ids.submit_button.disabled = False
class SecondWindow(Screen):
def on_pre_enter(self):
Window.size = (500,500)
Window.clearcolor = (0,0,0,0)
pass
class WindowManager(ScreenManager):
pass
class MyMainApp(App):
def build(self):
return kv
kv = Builder.load_file("my.kv")
if __name__ == "__main__":
MyMainApp().run()

For your current design you can control it from outside as,
First set properties in SecondWindow for setting the angle, stretch instruction etc. and then control them depending on the state of those (weak reference of the check boxes) checkbox_confirm_mode etc. from the MainWindow as,
class SecondWindow(Screen):
angle = NumericProperty(0)
allow_strech = BooleanProperty(False)
def on_pre_enter(self):
screen = self.manager.get_screen("main")
angle_value = screen.ids.checkbox_confirm_mode.active
stretch_value = screen.ids.checkbox_confirm_stretch.active
self.angle = 90*angle_value # Less calculation.
self.allow_strech = stretch_value # Less calculation.
Window.size = (500,500)
...
Now in the kvlang of SecondWindow,
<SecondWindow>:
id: second_window
name: "second"
canvas:
Rotate:
angle: root.angle
origin: self.center
Image:
source: 'Troy.png'
keep_ratio: True
allow_stretch: root.allow_strech

How to add an action bar in kivy using screenmanager widget?

I am trying to add an action bar on top in the first screen of my project. I tried using screenmanager widget and sending the action bar as it's children like how to manage/get both of the screens. At first I tried just adding the action bar code in root.widget in the first screen, but they are showing the class for this as an invalid class.
How to add both of them? Also I can't show the buttons from top to bottom even though I added orientation : 'vertical'
import kivy
kivy.require('1.10.1')
from kivy.app import App
from kivy.uix.button import Button
from kivy.uix.boxlayout import BoxLayout
from kivy.lang import Builder
from kivy.uix.gridlayout import GridLayout
from kivy.uix.screenmanager import ScreenManager,Screen,FadeTransition
class SomeLayout_GridLayout(Screen):
pass
class FirstScreen(Screen):
pass
class SecondScreen(Screen):
pass
class ScreenManager(ScreenManager):
pass
root_widget = Builder.load_string('''
ScreenManager:
FirstScreen:
SecondScreen:
SomeLayout_GridLayout:
<FirstScreen>:
name: 'first'
<SomeLayout_GridLayout>:
cols: 1
rows: 2
row_force_default: True
rows_minimum: {0: ActionBar.height, 1: self.height - ActionBar.height}
SomeMenu_ActionBar:
id: ActionBar
<SomeMenu_ActionBar#ActionBar>:
ActionView:
id: ActionView
ActionGroup:
id: App_ActionGroup
mode: 'spinner'
text: 'App'
ActionButton:
text: 'Settings'
on_press: app.open_settings()
ActionButton:
text: 'Quit'
on_press: app.get_running_app().stop()
ActionGroup:
id: File_ActionGroup
mode: 'spinner'
text: 'File'
ActionButton:
text: 'Open'
ActionButton:
text: 'Save'
<HiddenIcon_ActionPrevious#ActionPrevious>:
title: app.title if app.title is not None else 'Action Previous'
with_previous: False
app_icon: ''
app_icon_width: 0
app_icon_height: 0
size_hint_x: None
width: len(self.title) * 10
<HiddenText_ActionPrevious#ActionPrevious>: #
with_previous: False
on_press: print(self)
title: ''
<Hidden_ActionPrevious#ActionPrevious>:
with_previous: False
on_press: print(self)
title: ''
size_hint: None, None
size: 0, 0
BoxLayout:
orientation: 'horizontal'
BoxLayout:
Button:
text: 'Crime Prediction'
font_size: 30
on_release: app.root.current = 'second'
Button:
text: 'Forum'
font_size: 30
on_release: app.root.current = 'second'
Button:
text: 'Probable Suspect'
font_size: 30
on_release: app.root.current = 'second'
<SecondScreen>:
name: 'second'
BoxLayout:
orientation: 'vertical'
Label:
text: 'Predict Crime Nigga!'
font_size: 50
BoxLayout:`enter code here`
Button:
text: 'Back to Main Menu'
font_size: 30
on_release: app.root.current = 'first'
Button:
text: 'get random colour screen'
font_size: 30
on_release: app.root.current = 'first'
''')
class ScreenManagerApp(App):
def build(self):
return root_widget
ScreenManagerApp().run()

Kivy App with ActionBar & ScreenManager
Declare a root widget with inheritance of BoxLayout
Add ActionBar as child of root widget
Add ScreenManager as child of root widget, and with id: sm
Snippets
BoxLayout:
orientation: 'vertical'
ActionBar:
...
ScreenManager:
id: sm
FirstScreen:
SecondScreen:
Example
main.py
from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.lang import Builder
class WelcomeScreen(Screen):
pass
class FirstScreen(Screen):
pass
class SecondScreen(Screen):
pass
class ScreenManager(ScreenManager):
pass
class CrimePrevention(BoxLayout):
pass
Builder.load_file("main.kv")
class TestApp(App):
title = 'Kivy ScreenManager & ActionBar Demo'
def build(self):
return CrimePrevention()
if __name__ == '__main__':
TestApp().run()
main.kv
#:kivy 1.11.0
#:import sp kivy.metrics.sp
#:import dp kivy.metrics.dp
<CrimePrevention>:
orientation: 'vertical'
canvas.before:
Color:
rgb: .6, .6, .6
Rectangle:
pos: self.pos
size: self.size
# source: 'data/background.png'
SomeMenu_ActionBar:
id: ActionBar
ScreenManager:
id: sm
WelcomeScreen:
FirstScreen:
SecondScreen:
<SomeMenu_ActionBar#ActionBar>:
ActionView:
id: ActionView
HiddenIcon_ActionPrevious:
ActionGroup:
id: App_ActionGroup
mode: 'spinner'
text: 'Jump to Screen'
ActionButton:
text: 'Crime Prediction'
on_release: app.root.ids.sm.current = 'second'
ActionButton:
text: 'Forum'
on_release: app.root.ids.sm.current = 'second'
ActionButton:
text: 'Probable Suspect'
on_release: app.root.ids.sm.current = 'second'
ActionGroup:
id: App_ActionGroup
mode: 'spinner'
text: 'App'
ActionButton:
text: 'Settings'
on_press: app.open_settings()
ActionButton:
text: 'Quit'
on_press: app.get_running_app().stop()
ActionGroup:
id: File_ActionGroup
mode: 'spinner'
text: 'File'
ActionButton:
text: 'Open'
ActionButton:
text: 'Save'
<HiddenIcon_ActionPrevious#ActionPrevious>:
title: '' # app.title if app.title is not None else 'Action Previous'
with_previous: False
app_icon: ''
app_icon_width: 0
app_icon_height: 0
size_hint_x: None
width: len(self.title) * 10
<WelcomeScreen>:
name: 'welcome'
Label:
text: 'Welcome Screen'
font_size: sp(50)
<FirstScreen>:
name: 'first'
Label:
text: 'First Screen'
<SecondScreen>:
name: 'second'
BoxLayout:
orientation: 'vertical'
Label:
text: 'Predict Crime'
font_size: 50
BoxLayout:
Button:
text: 'Back to Main Menu'
font_size: 30
on_release: app.root.ids.sm.current = 'first'
Button:
text: 'get random colour screen'
font_size: 30
on_release: app.root.ids.sm.current = 'first'
Output

No Screen with name

All my program works up-to a point and I'm road blocked by it.
My program loads some starter screens in the main app.
Based on user input the program loads a completely different sub app.
Problem occurs when trying to change screens in the loaded sub app
Here is the code where the problem exists:
The .py file:
import kivy
kivy.require('1.10.0')
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.screenmanager import Screen, ScreenManager, FadeTransition
from kivy.uix.button import Button
from kivy.uix.label import Label
chClass = ""
class ScreenManage(ScreenManager):
pass
class Home(ScreenManager):
pass
class TitleScreen(Screen):
pass
class GameScreen(Screen):
pass
class ClassScreen(Screen):
pass
class Warrior1(Screen):
def GetChClass(self, ch):
return ch
def build(self):
ExecuteW().run()
class Acrobat1(Screen):
def GetChClass(self, ch):
return ch
class Spell1(Screen):
def GetChClass(self, ch):
return ch
class HomeScreen(Screen):
pass
class WarriorStats(Screen):
pass
class AcrobatStats(Screen):
pass
class SpellCasterStats(Screen):
pass
class ExecuteW(App):
def build(self):
return Home()
class RevengeApp(App):
def build(self):
return ScreenManage()
if __name__ == '__main__':
print chClass
RevengeApp().run()
revenge.kv:
#: import sm kivy.uix.screenmanager
#: import Factory kivy.factory.Factory
#: import builder kivy.lang.Builder
<ScreenManage>
transition: sm.FadeTransition()
TitleScreen:
ClassScreen:
GameScreen:
Warrior1:
Acrobat1:
Spell1:
WarriorStats:
<TitleScreen>
on_touch_down: app.root.current = 'Game'
canvas:
Rectangle:
size: self.size
pos: self.pos
source: 'KnightArmor.jpg'
BoxLayout:
orientation: 'vertical'
Label:
font_size: '30sp'
color: 1,0,0,1
text: "Warrior's Revenge"
Label:
color: 1,0,0,1
text: "Click to Continue:"
<GameScreen>
name: 'Game'
canvas:
Rectangle:
size: self.size
pos: self.pos
source: 'KnightArmor.jpg'
BoxLayout:
Button:
size_hint: .5,.1
text: "New Game"
on_release: app.root.current = 'Class'
Button:
size_hint: .5,.1
text: "Load Game"
<ClassScreen>
name: 'Class'
BoxLayout:
orientation: 'vertical'
Label:
text: "Choose Your Path"
Button:
text: "Warrior"
on_release: app.root.current = "Warrior1"
Button:
text: "Acrobat"
on_release: app.root.current = "Acrobat1"
Button:
text: "Spell Caster"
on_release: app.root.current = "Spell1"
<Warrior1>
name: "Warrior1"
canvas:
Rectangle:
size: self.size
pos: self.pos
source: "Warrior.jpg"
BoxLayout:
orientation: 'vertical'
Label:
font_size: "20sp"
text: "Warrior's are physically strong"
color: 0,.5,1,1
Label:
font_size: "20sp"
text: "experts in hand to hand combat,"
color: 0,.5,1,1
Label:
font_size: "20sp"
text: "and knowledgeable in the ways of"
color: 0,.5,1,1
Label:
font_size: "20sp"
text: "arms and armor"
color: 0,.5,1,1
BoxLayout:
orientation: 'horizontal'
Button:
text: "Cancel"
on_release: app.root.current = "Class"
Button:
name: "warrior_confirm"
text: "Confirm"
on_release: chClass = root.GetChClass('Warrior')
on_release: root.build()
executew.kv:
#: import sm kivy.uix.screenmanager
<Home>:
transition: sm.FadeTransition()
HomeScreen:
WarriorStats:
<HomeScreen>
name: 'Home'
AnchorLayout:
Button:
text: "Stats"
on_release: app.root.current = 'WStats'
<WarriorStats>
name: 'WStats'
canvas:
Rectangle:
size: self.size
pos: self.pos
source: "Warrior.jpg"
The problem:
When clicking the stats button on the home screen in executew the WarriorStats screen named 'WStats' should be loaded, but I get the error "no screen with name 'WStats'"

Answer that I figured out on my own
class HomeScreen(Screen):
def switch(self):
self.manager.current = "WStats"
And in executew:
<HomeScreen>
Button:
text: "Stats"
on_release: root.switch()