I created a stack layout with 100 buttons in it. This alone works but when I add the stack layout under scroll view layout nothing is displayed on the screen.without using scroll view
when scroll view is used
Python code
from kivy.app import App
from kivy.metrics import dp
from kivy.uix.stacklayout import StackLayout
from kivy.uix.widget import Widget
from kivy.uix.button import Button
from kivy.uix.scrollview import ScrollView
class stacklayoutex(StackLayout):
def __init__(self,**kwargs):
super().__init__(**kwargs)
for i in range(100):
b=Button(text=str(i+1),size_hint=(None,None),size=(dp(100),dp(100)))
self.add_widget(b)
class MainWidget(Widget):
pass
class TheLabApp(App):
pass
TheLabApp().run()
KV file
scrollviewex:
<scrollviewex#ScrollView>:
stacklayoutex:
size_hint: 1,None
height:4000
<stacklayoutex>:
A couple problems:
Your class names must begin with upper case. Not following this rule can cause syntax errors in your kv.
Also, indentation error in your kv, it should be:
Scrollviewex:
<Scrollviewex#ScrollView>:
Stacklayoutex:
size_hint: 1,None
height:4000
<Stacklayoutex>:
Related
im really new in Kivy and i would like to make an app where i could create a MDIconButton that is draggable, and if possible, droppable in any BoxLayout? Is that possible in KivyMD or Kivy? Also is there a Kivy function where whenever I hold down a button, it'll display some kind of small dialogue box that contains details that can be entered by the user. thanks!
Rather than use Drag-N-Drop from kivy-garden just use the DragBehavior class! It comes directly installed with Kivy and it'll save you having to install kivy-garden.
https://kivy.org/doc/stable/api-kivy.uix.behaviors.drag.html
Here is some example code of how it's used:
from kivy.uix.label import Label
from kivy.app import App
from kivy.uix.behaviors import DragBehavior
from kivy.lang import Builder
# You could also put the following in your kv file...
kv = '''
<DragLabel>:
# Define the properties for the DragLabel
drag_rectangle: self.x, self.y, self.width, self.height
drag_timeout: 10000000
drag_distance: 0
FloatLayout:
# Define the root widget
DragLabel:
size_hint: 0.25, 0.2
text: 'Drag me'
'''
class DragLabel(DragBehavior, Label):
pass
class TestApp(App):
def build(self):
return Builder.load_string(kv)
TestApp().run()
I am trying to change to another screen by swiping the screen. I've tried carousel but it seems that it only works with images, so I've tried detecting a swipe motion and changing the screen after it has been detected.
main.py
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.screenmanager import Screen
from kivy.uix.button import ButtonBehavior
from kivy.uix.image import Image
from kivy.uix.label import Label
from kivy.uix.carousel import Carousel
from kivy.uix.widget import Widget
from kivy.uix.popup import Popup
class HomeScreen(Screen):
def on_touch_move(self, touch):
if touch.x < touch.ox: # this line checks if a left swipe has been detected
MainApp().change_screen(screen_name="swipedhikr_screen") # calls the method in the main app that changes the screen
class ImageButton(ButtonBehavior, Image):
pass
class LabelButton(ButtonBehavior, Label):
pass
class SettingsScreen(Screen):
pass
class SwipeDhikrScreen(Screen):
pass
#def quit_verification():
# pop = Popup(title="verification", content=Label(text= "Are you sure?"))
GUI = Builder.load_file("main.kv")
class MainApp(App):
def build(self):
return GUI
def change_screen(self, screen_name):
# get the screen manager from the kv file
screen_manager = self.root.ids["screen_manager"]
screen_manager.transition.direction = "up"
screen_manager.current = screen_name
def quit_app(self):
MainApp().stop()
MainApp().run()
I got an attribute error: "None type object has no attribute 'ids'"
MainApp().change_screen(screen_name="swipedhikr_screen")
This line creates a new instance of MainApp, which doesn't have any widgets and therefore naturally fails when you try to access them.
Use the existing instance of MainApp, i.e. the one that you're actually running, via MainApp.get_running_app().
Also you are not correct that Carousel works only with images.
I am having problems understanding the usage of custom Properities and ways of binding methods to events.
Here's my code:
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.label import Label
from kivy.uix.button import Button
from kivy.properties import StringProperty
kivy_lang = '''
<MainWidget>:
on_my_property: my_label.text = 'from button bind method via StringProperty' + my_property
Label:
id: my_label
text: root.my_property
Button:
id: my_button
text: 'intro button'
'''
class MainWidget(BoxLayout):
# bind some properties
my_property = StringProperty('0')
def __init__(self, **kwargs):
super(MainWidget, self).__init__(**kwargs)
# if needed to do sth on widget construction
self.ids.my_button.bind(on_press=self.my_method)
def my_method(self,*args,**kwargs):
self.my_property = str(int(self.my_property)+1)
self.ids.my_button.text = 'new'
class MyApp(App):
def build(self):
Builder.load_string(kivy_lang)
return MainWidget()
if __name__ == '__main__':
MyApp().run()
When I run it it renders OK, but when I click a button, as a result I get
NameError: name 'my_property' is not defined
I tried binding method for Button in kv lang with (and removing whole 'init()' on python side):
on_press: root.my_method
and then when I press button the app doesn't crash but nothing happens
Can someone explain me how to adjust this code to work?
I understand the code is a little 'mixed techniques' but I did it that way to get to know different approaches, so I would appreciate if You don't turn it all around :)
1/ you are missing 'self' before 'my_property' in 'on_my_property' bindind, hence the crash
2/ in kv bindings. the python code is called as written, so you need '()' after 'root.my_method', or the statement has no effect.
In theory, putting a Kivy-Label into a Stack Layout (or into some other layout) should be the easiest and most common thing - but it is currently plunging me into despair. The following syntax displays a plain single-button app (under Kivy 1.8 or 1.9, Win 7) until I uncomment the Label-generating line, which consistently fails with messages such as AttributeError: 'LabelPygame' object has no attribute 'bind' or AttributeError: 'LabelSDL2' object has no attribute 'bind' (in layout.py):
from kivy.app import App
from kivy.uix.button import Button
from kivy.core.text import Label
from kivy.uix.stacklayout import StackLayout
class TestApp(App):
def build(self):
mylayout = StackLayout(orientation='lr-tb')
mylayout.add_widget(Button(text='This button can always be rendered.'))
# mylayout.add_widget(Label(text='This label seems to cause trouble.'))
return mylayout
TestApp().run()
I have a hunch that I am overlooking something really-really obvious or silly, but cannot get at what it is. An alternative invocation based on the Builder and runTouchApp appears to work just fine (the kind of Layout did not seem to make a difference):
# ... other imports abbreviated ...
Builder.load_string('''
<MyLayout>:
Button:
text: "This button can always be rendered."
Label:
text: "This label works in this case."
''')
class MyLayout(FloatLayout):
pass
runTouchApp(MyLayout())
You're importing kivy.core.text.Label, but you really want kivy.uix.label.Label.
I would like to create a scrollable Floatlayout with dynamically created buttons (kind of paint where I can scroll the drawing board). Unfortunately, the code that I come out doesn't work and the buttons don't move while scrolling the FloatLayout. How can I attach the button to the FloatLayout?
import kivy
kivy.require('1.0.7')
from kivy.app import App
from kivy.uix.scrollview import ScrollView
from kivy.lang import Builder
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.button import Button
Builder.load_string('''
<Scroller>
view: glayout
FloatLayout:
id: glayout
width: 2000
height: 2000
size_hint: (None, None)
''')
class Main(App):
def build(self):
self.root=Scroller()
return self.root
class Scroller(ScrollView):
def __init__(self, **kwargs):
super(Scroller, self).__init__(**kwargs)
a = Button(size_hint=(None,None), width=200, height=200)
self.ids.glayout.add_widget(a)
a.bind(pos=self.ids.glayout.pos)
if __name__ in ('__main__'):
app = Main()
app.run()
The FloatLayout handle the size, not the position. The most simple solution is to replace your FloatLayout with a RelativeLayout, which handle size, and position is relative to the RelativeLayout origin.