Kivy Layout Issue - kivy

I am trying to create a GUI using Kivy. However, I cannot resolve some formatting issues.
Here is a slimmed down version of my KV file:
BoxLayout:
MainCanvas:
size_hint: 1,1
size: (root.width,root.height*.9)
DoubleEllipseWidget:
ActionBar:
id: _action
size_hint: 1,0.1
size: (root.width,root.height*.1)
pos_hint: {'bottom':1}
ActionView:
use_separator: True
ActionPrevious:
title: 'Test App:'
with_previous: False
ActionOverflow:
disabled: True
ActionButton:
important: True
text: 'Button 1'
#on_release: some_function
ActionButton:
text: 'Button 2'
#on_release: some_function
ActionButton:
text: 'Button 3'
#on_release: some_function
<DoubleEllipseWidget>
size: [200, 200]
canvas:
Color:
rgba: 0, 0, 0, 1
Ellipse
size: [198, 198]
pos: [600-200-100, 800-200-100]
Color:
rgba: 1, 1, 1, 1
Ellipse
size: [200, 200]
pos: [600-200-100, 800-200-100]
TextInput:
on_parent:self.focus = True
text: 'center of circle'
background_color: (0,0,0,0)
foreground_color: (0,0,0,1)
What I am trying to get to is very easily explained.
Essentially, there should be a menu bar running horizontally along the screen window (10% of total height and 100% of width). I believe I have done this.
The remaining 95% height should be the main canvas - I believe I have also done this.
The final part is getting a particular widget to be placed into the center of the main canvas. This is where I am stuck and would appreciate some help.
The widget I need to center is made up of two circles (one centered on top of the other, with one being slightly smaller than the other). Then, on top of the top-most circle should be a TextInput.

After taking the advice from this community, I stripped all of the logic back until I was left with just the basics (class definitions and layout), and was still having issues.
However, I have now learnt that what I assumed was a layout issue was likely not. A Kivy bug report last commented on in Nov 2018 (TextInput focus problem #3863), suggests there are unexplained instances where textinputs can lose focus. Below is the suggested workaround which also worked for me. Thanks for those that tried to help me.
from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.popup import Popup
from kivy.uix.textinput import TextInput
from kivy.lang import Builder
Builder.load_string('''
<Base>:
Button:
text: 'Press for Popup'
on_press: root.edit_text()
<TextInputX>
id: texter
keyboard_mode: 'managed'
is_focusable: True
focus: True
keyboard_on_key_down:
texter.show_keyboard()
''')
class Base(BoxLayout):
def __init__(self, **kwargs):
super(Base, self).__init__(**kwargs)
def edit_text(self, *args):
self.clear_widgets()
content = TextInputX()
# content.focus = True
popup = Popup(content=content)
popup.open()
class TextInputX(TextInput):
def __init__(self, **kwargs):
super(TextInputX, self).__init__(**kwargs)
# self.focus = True
class SampleApp(App):
def build(self):
return Base()
if __name__ == '__main__':
SampleApp().run()

Related

How to disable a widget when a button from a different class is pressed?

Im making a Button which disables a TopAppBar menu form my user interface, the problem is that the Button is on one class an the TopAppBar in another, because one belongs to the screen and the other is shared between multiple screens.
code:
from kivymd.app import MDApp
from kivy.lang import Builder
from kivy.core.window import Window
from kivymd.uix.screen import MDScreen
Window.size = (300, 500)
navigation_helper = """
<UserScreen>
name: 'user_screen'
MDBoxLayout:
orientation: "vertical"
pos_hint: {"top": 1}
adaptive_height: True
padding: (0, "80dp" , 0, 0)
FloatLayout:
MDRaisedButton:
id: save_btn_user
text: "Guardar"
md_bg_color: "white"
text_color: "black"
font_size: 16.2
pos_hint: {"left":1, "bottom": 1}
size_hint: (.2,.2)
disabled: True
on_press: root.save_btn_press()
MDRaisedButton:
id: edit_btn_user
text: "Editar"
md_bg_color: "white"
text_color: "black"
font_size: 16.2
pos_hint: {"right":1, "bottom": 1}
size_hint: (.2,.2)
disabled: False
on_press:
root.disable_top_bar()
<MainScreen>:
name: "main_screen"
BoxLayout:
orientation: 'vertical'
MDTopAppBar:
id: title_bar
title: 'Dietas'
md_bg_color: 0.08,0.07,0.45
specific_text_color: 1,1,1
left_action_items: [["menu", lambda x: nav_drawer.set_state('toggle')]]
Widget:
MDNavigationLayout:
ScreenManager:
id: scr
UserScreen:
MDNavigationDrawer:
id: nav_drawer
BoxLayout:
orientation: 'vertical'
spacing: '8dp'
ScrollView:
MDList:
OneLineIconListItem:
text: 'Usuario'
on_press:
scr.current= 'user_screen'
title_bar.title = "Usuario"
nav_drawer.set_state('close')
IconLeftWidgetWithoutTouch:
icon: 'account'
on_press:
scr.current= 'user_screen'
title_bar.title = "Usuario"
nav_drawer.set_state('close')
MainScreen:
"""
class UserScreen(MDScreen):
def disable_top_bar(self):
self.a=MainScreen()
self.a.disable_top_barr()
class MainScreen(MDScreen):
def disable_top_barr(self):
self.ids.title_bar.disabled = True
print("testmsg")
class DemoApp(MDApp):
def build(self):
self.theme_cls.theme_style = ("Dark")
screen = Builder.load_string(navigation_helper)
return screen
DemoApp().run()
As you may have seen, I tried creating two method, one in the TopAppBar class disabling it and printing a test message(that its shown) and the other in the Button class calling that function.
With the following approach
def disable_top_bar(self):
self.a=MainScreen()
self.a.disable_top_barr()
you will see no change in your GUI because each time you call that method, it will create a new instance of MainScreen (which is not related to your GUI) and call the asked method on it.
In order to access that specific instance you can use the method get_running_app of MDApp as follows,
def disable_top_bar(self):
# First access the running app instance.
app = MDApp.get_running_app()
# Access the target screen that you set as the root widget.
main_screen = app.root
# Call the method.
main_screen.disable_top_barr()
As a note avoid using predefined names like a, b, g etc. when working with KivyMD widgets.

How do I keep KivyMD bottom app toolbar on multiple screens

I am trying to keep the KivyMD toolbar on multiple screens, I have searched on stackoverflow before, and found out I may need to create a class and inherit it. Question: Is this right, if yes I would be very grateful is you could make a sample of the class, and if no I would equally be grateful for your opinion.. Thanks.
Here's my .py file
from kivymd.app import MDApp
from kivy.uix.screenmanager import Screen, ScreenManager, NoTransition
from kivy.core.window import Window
Window.size = (300, 500)
class Screen1(Screen):
pass
class Screen2(Screen):
pass
class TwoScreenApp(MDApp):
def build(self):
self.theme_cls.primary_palette = 'Gray'
self.sm = ScreenManager(transition=NoTransition())
self.sm.add_widget(Screen1(name='screen1'))
self.sm.add_widget(Screen2(name='screen2'))
return self.sm
def change_screen(self, screen):
self.sm.current = screen
"""I am using this self.sm method to link
icon to screen2 until I find a better way"""
TwoScreenApp().run()
and Here's my .kv file
ScreenManager:
Screen1:
Screen2:
<Screen1>
name: 'screen1'
MDBoxLayout:
md_bg_color: (240/255, 240/255, 240/255, 1)
orientation: 'vertical'
MDLabel:
halign: 'center'
text:
"""With the production of the Model T automobile,
Henry Ford had an unforeseen and tremendous
impact on American life. He became regarded
as an apt symbol of the transition from an
agricultural to an industrial America."""
MDBottomAppBar:
MDToolbar:
icon: "account-circle"
type: "bottom"
left_action_items: [["arrow-right", lambda x: app.change_screen("screen2")], ["alpha-x-circle", lambda x: x]]
right_action_items: [["alpha-y-circle", lambda x: x], ["arrow-left", lambda x: app.change_screen("screen1")]]
elevation: 10
<Screen2>
name: 'screen2'
md_bg_color: (240/255, 240/255, 240/255, 1)
MDBoxLayout:
md_bg_color: (255/255, 255/255, 255/255, 1)
orientation: 'vertical'
MDLabel:
halign: 'center'
text:
"""The development of mass-production techniques, which
enabled the company eventually to turn out a Model T
every 24 seconds; the frequent reductions in the price
of the car made possible by economies of scale; and
the payment of a living wage that raised workers
above subsistence and made them potential customers
for, among other things, automobiles—these innovations
changed the very structure of society."""
MDBottomAppBar:
MDToolbar:
title: "Title"
icon: "account-circle"
type: "bottom"
left_action_items: [["menu", lambda x: app.change_screen("screen1")]]

Positioning images with FloatLayout

This is driving me insane. I'm trying to position an image to the top of the main window with FloatLayout. Below is a simplified example.
It seems that a button is fine, but an image defaults to a 100x100 square (yes, I think I've read that somewhere) and the top bounding box of the image is at the top of the screen, not the image.
How can I force the image (top of the rectangle) to the top of the window like the button is?
Screen_showing example_button_and_image
import kivy
kivy.require('1.10.0')
from kivy.app import App
from kivy.uix.button import Button
from kivy.uix.image import Image
from kivy.uix.floatlayout import FloatLayout
from kivy.config import Config
Config.set('graphics', 'width', '480')
Config.set('graphics', 'height', '800')
class MyApp(App):
def setOrientation(self, orient):
""""""
self.orient = orient
def build(self):
return FloatLayout()
if __name__ == "__main__":
app = MyApp()
app.setOrientation(orient="vertical")
app.run()
<FloatLayout>:
Image:
source: 'image_400x90.png'
pos_hint: {'left':1, 'top':1}
size_hint: None, None
allow_stretch: False
keep_ratio: True
Button:
font_size: 30
color: 0,1,0,1
size_hint: 0.3, 0.1
text: "TopRight"
pos_hint: {'right':1, 'top':1}
That happend because the Image is a Widget and "the real image" (the picture) is a texture of that Widget, and by default, the image is centered and fits inside the widget bounding box. If you don’t want that, you can set allow_stretch to True and keep_ratio to False. (docs)
For understand that you can add a canvas with a rectangle in the Image Widget like this:
Image:
canvas:
Color:
rgba: 1, 1, 1, 0.5
Rectangle:
pos: self.pos
size: self.size
source: 'dog.jpg'
pos_hint: {'left':1, 'top':1}
size_hint: None, None
allow_stretch: True
keep_ratio: False
And then you can see why the image doesn't do what you want
another pic (the image(texture) is centered and fits inside the widget):
One thing you can do is set allow_stretch: True and keep_ratio: False
This is the result: (set the size with size_hint)
Favcau gives one solution above (and thanks), but I have found what I think is more obvious. All it needs is to have the size defined in the kv file.
Image:
id: image2
source: 'image_400x90.jpg'
pos_hint: {'left':1, 'top':1}
size_hint: None, None
size: 400, 90
allow_stretch: True
keep_ratio: False

Highlight a Kivy ToggleButton with mouse hovering

I am currently coding a GUI with Kivy. I need to modify a ToggleButton behaviour so that it is highlighted when hovered by the mouse. Here is my code so far:
class FilterToggle(ToggleButton):
def __init__(self, **kwargs):
Window.bind(mouse_pos=self.on_mouse_pos)
super(FilterToggle, self).__init__(**kwargs)
def on_mouse_pos(self, *args):
pos = args[1]
if self.collide_point(*pos):
print("I am on the good path!)
Here is my .kv file:
<FilterToggle>:
text_size: self.width - 20, None
valign: 'middle'
halign: 'left'
markup: True
.
.
.
FilterToggle:
text: "This is just to illustrate"
The on_mouse_pos() function never prints anything, as self.collide_point(*pos) always returns "False". I found that self.pos gives me the coordinates of all my FilterToggle widgets, so there is obviously an issue with my code.
Thanks a lot for helping a Python beginner!

Combining image and text within a button in kivy

What's the preferred way to combine an image/icon and text within a button? For example, how would you create a button with text = 'my button', and a graphical icon to the left of that text?
Regarding to question #2.
The way Kivy works is embedding Widget instances. Since Image and Button are subclasses of Widget, then all you have to do is embed an Image inside a the Button. Notice that the positioning inside a widget is fixed. You have to give explicit coordinates.
That said, you can always embed a Layout to organize the stuff you are putting inside the Button.
Here is the simple ex
from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.lang import Builder
Builder.load_string("""
<ButtonsApp>:
orientation: "vertical"
Button:
text: "B1"
Image:
source: 'kivy.png'
y: self.parent.y + self.parent.height - 200
x: self.parent.x
Label:
text: "A label"
""")
class ButtonsApp(App, BoxLayout):
def build(self):
return self
if __name__ == "__main__":
ButtonsApp().run()
EDIT: An example of how a relative layout can be embedded inside a button
In this case I am using a StackLayout to organize an Image and a Label inside. As I said, Button is a Widget and Kivy works embedding widgets inside widgets. It doesn't matter if they are labels, buttons or layouts.
from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.lang import Builder
Builder.load_string("""
<ButtonsApp>:
orientation: "vertical"
Button:
StackLayout:
pos: self.parent.pos
size: self.parent.size
orientation: 'lr-tb'
Image:
source: 'kivy.png'
size_hint_x: None
width: 74
Label:
size_hint_x: None
width: 100
text: "The text"
Label:
text: "A label"
""")
class ButtonsApp(App, BoxLayout):
def build(self):
return self
if __name__ == "__main__":
ButtonsApp().run()
Meanwhile, there is another way.
You can use icon fonts such as Font Awesome and combine them with text.
Either import the font directly and wrap the text in their font tag, or simply use some of the libraries that take care of that.
#: import icon ...
Button:
markup: True
text: "%s Comment" % icon('comment', 32)
size_hint_x: None
width: 100
Kivy-iconfonts converts css/tff combinations that are distributed for web sites into a json format that it loads during runtime using the import statement as shown in the example above.
I extended this in my fork to fetch Font Awesome icons during runtime and put them into the working directory of your application. That gives you the advantage of not having to distribute the fonts with the application.
Define a new Button class or modify the one in Kivy.uix.button
class MyButton(Button):
#add these three properties in the class
icon = ObjectProperty(None)
icon_size = (0,0)
icon_padding = NumericProperty(0) #Enter any default value like 50 if you will
#always use an icon, or specify this field
#while creating the button
def __init__(self, **kwargs):
#no changes here, just for reference
return super(MyButton, self).__init__(**kwargs)
KV file:
<MyButton>:
state_image: self.background_normal if self.state == 'normal' else self.background_down
disabled_image: self.background_disabled_normal if self.state == 'normal' else self.background_disabled_down
canvas:
Color:
rgba: self.background_color
BorderImage:
border: self.border
pos: self.pos
size: self.size
source: self.disabled_image if self.disabled else self.state_image
Color:
rgba: (1, 1, 1, 1) if root.icon != None else (1,1,1,0)
Rectangle:
source: root.icon
size: (self.texture_size[1],self.texture_size[1]) if self.icon_size == (0,0) else self.icon_size
pos: int(self.center_x - self.texture_size[0] / 2.)-dp(root.icon_padding), int(self.center_y - self.texture_size[1] / 2.)
Color:
rgba: 1, 1, 1, 1
Rectangle:
texture: self.texture
size: self.texture_size
pos: int(self.center_x - self.texture_size[0] / 2.)+dp(root.icon_padding), int(self.center_y - self.texture_size[1] / 2.)
Now just create a button widget
MyButton(text = 'Hello',icon = 'icon.png', icon_padding = 50)

Resources