Develop Reference

Can't change location of widgets in KivyMD

I'm trying to move MDLabel and MDRectangleFlatButton to the center of the screen, but both pos_hint and halign are getting ignored.
app.kv:
ScreenManager:
MainScreen:
<MainScreen>
name: 'main_screen'
BoxLayout:
orientation: 'vertical'
MDToolbar:
title: 'My App'
MDLabel:
text: 'Welcome again!'
pos_hint: {'center_x': 0.5, 'center_y': 0.5}
style: 'H5'
MDRectangleFlatButton:
text: 'Enter'
pos_hint: {'center_x': 0.5, 'center_y': 0.5}
app.py:
from kivymd.app import MDApp
from kivy.lang import Builder
from kivy.uix.screenmanager import Screen, ScreenManager
class MainScreen(Screen):
pass
sm = ScreenManager()
sm.add_widget(MainScreen(name="main_screen"))
class MyApp(MDApp):
def build(self):
return Builder.load_file("app.kv")
MyApp().run()

Kivy Inherit ScreenManager from FloatLayout

I am having trouble understanding how to inherit the functionality of one class into another with Kivy. I understand the error message ('LoadDialog_Directory' object has no attribute 'manager'), but I'm just not grasping exactly how to fix it. I believe I need to do something with the function below, but ultimately, I do not know.
def __init__(self, **kwargs):
super().__init__(**kwargs)
The goal of this script is to be able to select a specific driver as the path for the filechooser. I choose this method vs. others because most were using Kivy 1.11.1, this version has a lot of deprecated functions that do not work with 2.0.
.py
from kivy.app import App
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.lang.builder import Builder
from kivy.uix.spinner import SpinnerOption
from kivy.uix.popup import Popup
from kivy.uix.button import Button
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.floatlayout import FloatLayout
from kivy.properties import ObjectProperty
from kivy.utils import platform
from kivy.properties import StringProperty
import os
import string
class WindowManager(ScreenManager):
pass
class MyOption(SpinnerOption):
pass
class LoadDialog_Directory(FloatLayout):
load = ObjectProperty(None)
cancel = ObjectProperty(None)
def dir_driver(self):
x = self.manager.get_screen("first")
return str(x.ids.drive_dir.text)
class FirstWindow(Screen):
def get_drives(self):
drives = ['%s:' % d for d in string.ascii_uppercase if os.path.exists('%s:' % d)]
return drives
def dismiss_popup(self):
self._popup.dismiss()
def show_load_directory(self):
content = LoadDialog_Directory(load=self.directroy_path, cancel=self.dismiss_popup)
self._popup = Popup(title="Load file", content=content, size_hint=(0.9, 0.9))
self._popup.open()
def directroy_path(self, path, filename):
self.ids.text_input_directory.text = str(filename[0])
self.dismiss_popup()
kv_main = Builder.load_file('main.kv')
#
class MyApp(App):
def build(self):
return kv_main
if __name__ == '__main__':
MyApp().run()
main.kv
#:include first.kv
WindowManager:
FirstWindow:
<LoadDialog_Directory>:
BoxLayout:
size: root.size
pos: root.pos
orientation: "vertical"
FileChooserListView:
id: filechooser
dirselect: True
path: root.dir_driver()
BoxLayout:
size_hint_y: None
height: 30
Button:
text: "Cancel"
on_release: root.cancel()
Button:
text: "Load"
on_release: root.load(filechooser.path, filechooser.selection)
first.kv
<FirstWindow>
name: 'first'
GridLayout:
cols: 1
BoxLayout:
orientation: "horizontal"
TextInput:
BoxLayout:
orientation: "horizontal"
Spinner:
id: drive_dir
text: "Root Drive"
halign: 'center'
option_cls: "MyOption"
values: root.get_drives()
Button:
text: "Set Result Directory"
on_release: root.show_load_directory()
TextInput:
id: text_input_directory
disabled: True
text: text_input_directory.text
BoxLayout:
size_hint: (0.01, 1)
orientation: "horizontal"
TextInput:
Side Note: The reason for the extra blank TextInput is because the Spinner will not function (show drivers) if it is taking too much of the App.

After a few hours of trail and error I finally got it to work, but I have no idea why it works. Here is what changed:
New variable in class LoadDialog_Directory(FloatLayout) - input_pth
Called input_pth into my content variable within class FirstWindow(Screen) function show_load_directory(self)
Set my filechooser.path to root.input_pth in the main.kv file.
I do not understand how the input_pth variable within content is able to reference the class LoadDialog_Directory(FloatLayout) without having to pass something like:
def __init__(self, input_pth, **kwargs):
super(LoadDialog_Directory, self).__init__()
self.input_pth = input_pth
.py
from kivy.app import App
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.lang.builder import Builder
from kivy.uix.spinner import SpinnerOption
from kivy.uix.popup import Popup
from kivy.uix.button import Button
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.floatlayout import FloatLayout
from kivy.properties import ObjectProperty
from kivy.utils import platform
from kivy.properties import StringProperty
import os
import string
class WindowManager(ScreenManager):
pass
class MyOption(SpinnerOption):
pass
class LoadDialog_Directory(FloatLayout):
input_pth = StringProperty()
load = ObjectProperty()
cancel = ObjectProperty()
class FirstWindow(Screen):
def drive_list(self):
drives = ['%s:' % d for d in string.ascii_uppercase if os.path.exists('%s:' % d)]
return drives
def dismiss_popup(self):
self._popup.dismiss()
def show_load_directory(self):
content = LoadDialog_Directory(load=self.directroy_path, cancel=self.dismiss_popup, input_pth=self.ids.drive_dir.text)
self._popup = Popup(title="Load file", content=content, size_hint=(0.9, 0.9))
self._popup.open()
def directroy_path(self, path, filename):
self.ids.text_input_directory.text = str(filename[0])
self.dismiss_popup()
kv_main = Builder.load_file('main.kv')
#
class MyApp(App):
def build(self):
return kv_main
if __name__ == '__main__':
MyApp().run()
main.kv
#:include first.kv
WindowManager:
FirstWindow:
<LoadDialog_Directory>:
BoxLayout:
size: root.size
pos: root.pos
orientation: "vertical"
FileChooserListView:
id: filechooser
dirselect: True
path: root.input_pth
BoxLayout:
size_hint_y: None
height: 30
Button:
text: "Cancel"
on_release: root.cancel()
Button:
text: "Load"
on_release: root.load(filechooser.path, filechooser.selection)
first.kv
<FirstWindow>
name: 'first'
GridLayout:
cols: 1
BoxLayout:
orientation: "horizontal"
TextInput:
BoxLayout:
orientation: "horizontal"
Spinner:
id: drive_dir
halign: 'center'
option_cls: "MyOption"
values: root.drive_list()
Button:
text: "Set Result Directory"
on_release: root.show_load_directory()
TextInput:
id: text_input_directory
disabled: True
text: text_input_directory.text
BoxLayout:
size_hint: (0.01, 1)
orientation: "horizontal"
TextInput:

Kivymd card button functionality

I have make a simple app using kivy,kivymd and python. on_release functionality in md card not working,my code snippet below.
from kivy.lang import Builder
from kivymd.app import MDApp
kv = '''
Screen:
MDCard:
size_hint: None, None
size: "280dp", "180dp"
pos_hint: {"center_x": .5, "center_y": .5}
ripple_behavior: True
on_release:print("worked")
'''
class TestCard(MDApp):
def build(self):
return Builder.load_string(kv)
TestCard().run()

You have to be careful with the tabs you use in your kv string. First of all you start with a tab before the Screen declaration. Thats not working. Then you have to set tabs after you declare the MDCard to set its attributes. Like this it works for me:
from kivy.lang import Builder
from kivymd.app import MDApp
KV = '''
Screen:
MDCard:
size_hint: None, None
size: "280dp", "180dp"
pos_hint: {"center_x": .5, "center_y": .5}
ripple_behavior: True
on_release: print("worked")
'''
class TestCard(MDApp):
def build(self):
return Builder.load_string(KV)
TestCard().run()

The problem with your code is python statements don't work in .kv files. Another problem is the indentation. So, just change the indentation and create a method in your TestCard class like this :
from kivy.lang import Builder
from kivymd.app import MDApp
kv = '''
Screen:
MDCard:
size_hint: None, None
size: "280dp", "180dp"
pos_hint: {"center_x": .5, "center_y": .5}
ripple_behavior: True
on_release: app.work()
'''
class TestCard(MDApp):
def build(self):
return Builder.load_string(kv)
def work(self):
print("worked")
TestCard().run()

Switching between kivy classes inside one screen

I'm looking for a way to change a part of a screen between 'DownPanel1' and 'DownPanel1' but I would like to avoide creating nex screen class 'ToAvoid'. Is it possible?
from kivy.config import Config
Config.set('graphics', 'multisamples', '0')
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.uix.boxlayout import BoxLayout
kv = '''
#:import FadeTransition kivy.uix.screenmanager.FadeTransition
ScreenManagement:
transition: FadeTransition()
SomeScreen:
ToAvoid:
<Menu#RelativeLayout>
id: main_menu
size_hint_x: None
width: 120
Button:
size_hint_y: None
pos: root.x, root.top - self.height
text: 'SomeScreen'
on_press: app.root.current = "SomeScreen"
<UpScreen>:
BoxLayout:
Button:
text: 'switch'
on_press: app.root.current = "ToAvoid"
<DownPanel1>:
Button:
text: 'DownPanel1'
#on_press:
<DownPanel2>:
Button:
text: 'DownPanel2'
#on_press:
<SomeScreen>:
name: 'SomeScreen'
BoxLayout:
orientation: 'horizontal'
Menu:
BoxLayout:
orientation: 'vertical'
UpScreen:
DownPanel1:
<ToAvoid>:
name: 'ToAvoid'
BoxLayout:
orientation: 'horizontal'
Menu:
BoxLayout:
orientation: 'vertical'
UpScreen:
DownPanel2:
'''
class DownPanel1(BoxLayout):
pass
class DownPanel2(BoxLayout):
pass
class UpScreen(Screen):
pass
class SomeScreen(Screen):
pass
class ToAvoid(Screen):
pass
class ScreenManagement(ScreenManager):
pass
sm = Builder.load_string(kv)
class TestApp(App):
def build(self):
return sm
if __name__ == '__main__':
TestApp().run()

How about some inception? Just put another ScreenManager inside of the other.
Try this example:
from kivy.app import App
from kivy.lang import Builder
KV = """
ScreenManager:
Screen:
name: "1st"
Button:
text: "next"
on_release:
root.current = "2nd"
Screen:
name: "2nd"
BoxLayout:
Button:
text: "3rd to avoid"
on_release:
root.current = "3rd"
ScreenManager:
id: sm2
Screen:
name: "inner1"
Button:
text: "go to inner 2"
on_release:
sm2.current = "inner2"
Screen:
name: "inner2"
Label:
text: "This is inner 2!"
Screen:
name: "3rd"
Label:
text: "To Avoid!"
"""
class MyApp(App):
def build(self):
return Builder.load_string(KV)
if __name__ == "__main__":
MyApp().run()

how to bind two or more events with on_text_validate

I want that on pressing enter in a TextInput widget it should do two things-
change the screen (i am using screen manager)
and search for the keyword
I do know that with on_text_validate we can perform either of the tasks by-
1.root.manager.current='namesomething'
2.root.function_which_has_search_algorithm()
is there anyway with which i can do both the things(changing_the_screen,calling_the_search_function) using on_text_validate or do i have to use some other technique?
here a sample code:
import kivy
kivy.require("1.10.0")
from kivy.app import App
from kivy.uix.screenmanager import ScreenManager,Screen
from kivy.lang import Builder
Builder.load_file('screenswitch.kv')
class MainScreen(Screen):
def SelectWord(self):
''' some search
code'''
class OtherScreen(Screen):
pass
sm = ScreenManager()
sm.add_widget(MainScreen(name='main'))
sm.add_widget(OtherScreen(name='other'))
class ScreenSwitchApp(App):
def build(self):
return sm
obj = ScreenSwitchApp()
obj.run()
heres my kivy code:
<MainScreen>:
BoxLayout:
TextInput:
text: "Search your word here"
color: 1,1,1,1
id: search_input
width: 200
size_hint: None, .20
pos_hint: {"center_x": .5, "center_y": 0.5}
multiline: False
on_text_validate: root.SelectWord() # i want this to change screen also
<OtherScreen>:
BoxLayout:
Button:
text: 'back to main screen'
on_press: root.manager.current='main'

A possible solution is to create a new function that calls that 2 functions:
*.py
import kivy
kivy.require("1.10.0")
from kivy.app import App
from kivy.uix.screenmanager import ScreenManager,Screen
from kivy.lang import Builder
Builder.load_file('screenswitch.kv')
class MainScreen(Screen):
def some_function(self):
self.SelectWord()
self.manager.current='other'
def SelectWord(self):
print("SelectWord")
class OtherScreen(Screen):
pass
sm = ScreenManager()
sm.add_widget(MainScreen(name='main'))
sm.add_widget(OtherScreen(name='other'))
class ScreenSwitchApp(App):
def build(self):
return sm
obj = ScreenSwitchApp()
obj.run()
*.kv
<MainScreen>:
BoxLayout:
TextInput:
text: "Search your word here"
color: 1,1,1,1
id: search_input
width: 200
size_hint: None, .20
pos_hint: {"center_x": .5, "center_y": 0.5}
multiline: False
on_text_validate: root.some_function() # i want this to change screen also
<OtherScreen>:
BoxLayout:
Button:
text: 'back to main screen'
on_press: root.manager.current='main'

TextInput:
id:qty_inp
size_hint_x:.1
multiline:False
on_text_validate:root.update_price()
on_text_validate:root.update_purchase
Like the above code you can add one more on_text_validate: root.method()