I'm trying to make an app with kivy and I want to be able to add a changeable amount of buttons with changeable text to a screen. Here's my code:
kv = Builder.load_file('main.kv')
class MyScreen(Screen):
def __init__(self, **kwargs):
super().__init__(**kwargs)
label = Label(text="hello world!")
for i in range(5):
self.ids.FillIn.add_widget(label)
class MainApp(App):
def build(self):
return kv
if __name__ == "__main__":
MainApp().run()
and kivy:
<WindowManager#ScreenManager>:
<MainPage#Screen>:
Button:
on_release: app.root.current = "MyPrayers"
<MyScreen#Screen>:
name: 'MyScreen'
BoxLayout:
orientation: "vertical"
BoxLayout:
orientation: "vertical"
id: FillIn
WindowManager:
MainPage:
MyScreen:
The main problem with your code is that the line of code:
kv = Builder.load_file('main.kv')
is executed before the definition of MyScreen is loaded. So the NyScreen instance that is created by the Builder.load_file() has none of the attributes of the later defined MyScreen class. Other issues involve trying to access ids in the __init__() method (which is executed before ids are assigned) and trying to add the same Label widget multiple times (any widget can have only one parent).
Here is a modified version of your python code that fixes the above issues:
class MyScreen(Screen):
def __init__(self, **kwargs):
super(MyScreen, self).__init__(**kwargs)
Clock.schedule_once(self.add_widgets)
def add_widgets(self, *args):
for i in range(5):
label = Label(text="hello world!")
self.ids.FillIn.add_widget(label)
class MainApp(App):
def build(self):
kv = Builder.load_file('main.kv') # load kv here, after MyScreen is defined
return kv
if __name__ == "__main__":
MainApp().run()
And the slightly modified kv:
<WindowManager#ScreenManager>:
<MainPage#Screen>:
Button:
text: 'Go To MyScreen'
on_release: app.root.current = "MyScreen"
<MyScreen>: # the #Screen is not needed since the MyScreen class is defined in the python code
name: 'MyScreen'
BoxLayout:
orientation: "vertical"
BoxLayout:
orientation: "vertical"
id: FillIn
WindowManager:
MainPage:
MyScreen:
I believe that my problem is that the label_text tag in the ScreenManager: section is not being updated when the change_text() function is run.Because it just shows the original label_text value, which in this case is nothing.
Does anyone know how get the tag to update? My goal is to be able to pass strings between the 2 Screen classes. So when a user enters something like a zip code on the previous screen i can pass it to the new screen.
#:kivy 1.1.3
ScreenManager:
id: screen_manager
SearchScreen:
id: search_screen
name: 'SearchScreen'
manager: screen_manager
ForecastScreen:
id: forecast_screen
name: 'ForecastScreen'
manager: screen_manager
label_text: search_screen.text
<SearchScreen>:
display: entry
FloatLayout:
TextInput:
id: entry
on_text_validate:
root.change_text()
<ForecastScreen>:
BoxLayout:
FloatLayout:
Label:
text:root.label_text
Then the py code:
class SearchScreen(Screen):
text = StringProperty('')
def change_text(self):
self.text = "show this text"
self.manager.current = "ForecastScreen"
class ForecastScreen(Screen):
label_text = StringProperty()
Builder.load_file('weather.kv')
sm = ScreenManager()
sm.add_widget(SearchScreen(name='SearchScreen'))
sm.add_widget(ForecastScreen(name='ForecastScreen'))
class WeatherApp(App):
def build(self):
return sm
if __name__ == "__main__":
WeatherApp().run()
First, on_text_validate will only be called when you press enter if the TextInput has the multiline property to False, so set it.
On the other hand I see that you do not understand the difference between:
Foo:
and
<Foo>:
In the first case you are creating an instance of Foo (and there can only be one element of this type) and in the second you are implementing a component. When you call Builder.load_file() and having that first element without "<" ">" that instance is returned, that is, there is already a ScreenManager, but in your case you have created another with python code. The ScreenManager instantiated in the .kv already has the Screen where the texts are already linked, and in changes those of Python are not. And when you return the ScreenManager created in python without the linked elements you observe a correct behavior, nothing will be modified.
What you have to do is remove the ScreenManager from the .py and use the .kv:
*.py
class SearchScreen(Screen):
text = StringProperty('')
def change_text(self):
self.text = "show this text"
self.manager.current = "ForecastScreen"
class ForecastScreen(Screen):
label_text = StringProperty("")
sm = Builder.load_file('weather.kv')
class WeatherApp(App):
def build(self):
return sm
if __name__ == "__main__":
WeatherApp().run()
*.kv
ScreenManager:
id: screen_manager
SearchScreen:
id: search_screen
name: 'SearchScreen'
ForecastScreen:
id: forecast_screen
name: 'ForecastScreen'
label_text: search_screen.text
<SearchScreen>:
display: entry
FloatLayout:
TextInput:
id: entry
multiline: False # <----
on_text_validate:
root.change_text()
<ForecastScreen>:
BoxLayout:
FloatLayout:
Label:
text: root.label_text
Goal:
Periodic update of parent (screen) class / UI from child (boxlayout) class. Theconf2.dat is occasionally updated (from various other screens), and I want the UI to update every 5 seconds or so by re-running this class.
Latest code update:
In the __init__ function, I have Clock.schedule_interval(self.create_button, 1), which should cause the create_button function to rerun every second.
At the top of the create_button function, I have self.box_share.clear_widgets(), which should clear all the widgets so they can be repopulated (per the instructions outlined further down the create_button function).
Action:
I run the code
I navigate to NoTags screen by clicking the button with text title 'updating sequence'
I make changes to buttons that were dynamically created under scrollview by clicking on them. They successfully change color. This information is written to the conf2.dat file.
I navigate to SequenceScreen screen by first clicking 'home' button, then clicking 'sequence display' button. This SequenceScreen screen is the screen I wish to have updated to reflect the changes made to conf2.dat file.
Result:
UI associated withSequenceScreen(Screen) class still does not update per changes made from UI associated with NoTags(Screen) class.
However, when I restart the app altogether, I find the SequenceScreen UI successfully updated.
Suspicion:
I'm just one line of code away from getting this UI to update properly.
Python Code:
from kivy.app import App
# kivy.require("1.10.0")
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen, FadeTransition
from kivy.uix.textinput import TextInput
from kivy.uix.gridlayout import GridLayout
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.button import Button
from kivy.uix.label import Label
from kivy.properties import NumericProperty
from kivy.clock import Clock
from kivy.uix.widget import Widget
from kivy.uix.scrollview import ScrollView
#from kivy.base import runTouchApp
from kivy.properties import StringProperty, ObjectProperty, NumericProperty
from kivy.storage.dictstore import DictStore
import pickle
import datetime, threading
import time
from kivy.clock import mainthread
class BackHomeWidget(Widget):
pass
class SequenceBoxLayout_NoEdits(BoxLayout):
box_share = ObjectProperty()
config_file = DictStore('conf2.dat')
def __init__(self, **kwargs):
super(SequenceBoxLayout_NoEdits, self).__init__(**kwargs)
self.orientation = "vertical"
Clock.schedule_interval(self.create_button, 1)
def create_button(self, *args):
self.box_share.clear_widgets()
top_button_share = 1.1
color = (.4, .4, .4, 1)
for i in range(25):
top_button_share -= .4
id_ = "part" + str(i + 1)
if self.config_file.exists(id_):
btn_color = self.config_file[id_]["background_color"]
else:
self.config_file.put(id_, background_color=color)
btn_color = color
button_share = Button(background_normal='',
background_color=btn_color,
id=id_,
pos_hint={"x": 0, "top": top_button_share},
size_hint_y=None,
height=60,
font_size = 30,
text= str(i+1)
self.box_share.add_widget(button_share)
#Clock.schedule_interval(self.parent.ids.updatedisplay.create_button(self, *args) , 1)
#self.parent.ids.updatedisplay.create_button(self, *args)
class SequenceBoxLayout_NoTag(BoxLayout):
box_share = ObjectProperty()
config_file = DictStore('conf2.dat')
def __init__(self, **kwargs):
super(SequenceBoxLayout_NoTag, self).__init__(**kwargs)
self.orientation = "vertical"
Clock.schedule_once(self.create_button)
def create_button(self, *args):
df = pd.read_excel("Test.xlsx","Sheet1")
parts = df['parts'].values.tolist()
top_button_share = 1.1
color = (.4, .4, .4, 1)
for i in range(len(parts)):
top_button_share -= .4
id_ = "part" + str(i + 1)
if self.config_file.exists(id_):
btn_color = self.config_file[id_]["background_color"]
else:
self.config_file.put(id_, background_color=color)
btn_color = color
button_share = Button(background_normal='',
background_color=btn_color,
id=id_,
pos_hint={"x": 0, "top": top_button_share},
size_hint_y=None,
height=60,
font_size = 30,
text= str(i+1)+ ". " + str(parts[i]))
if self.parent.name == 'notags':
button_share.bind(on_press=self.update_buttons_notag)
self.box_share.add_widget(button_share)
def update_buttons_notag(self, button):
button.background_color = 0.86,0.54,0.04,1
self.config_file.put(button.id, background_color=(0.86,0.54,0.04,1))
class MainScreen(Screen):
pass
class AnotherScreen(Screen):
pass
class SequenceScreen(Screen):
pass
class NoTags(Screen):
pass
class ScreenManagement(ScreenManager):
pass
presentation = Builder.load_file("updatelistexample.kv")
class MainApp(App):
def build(self):
return presentation
if __name__ == "__main__":
MainApp().run()
KV Code:
#: import FadeTransition kivy.uix.screenmanager.FadeTransition
ScreenManagement:
transition: FadeTransition()
MainScreen:
AnotherScreen:
NoTags:
SequenceScreen:
<SmallNavButton#Button>:
font_size: 32
size: 125, 50
color: 0,1,0,1
<BigButton#Button>:
font_size: 40
size_hint: 0.5, 0.15
color: 0,1,0,1
<BackHomeWidget>:
SmallNavButton:
on_release: app.root.current = "main"
text: "Home"
pos: root.x, root.top - self.height
<MainScreen>:
name: "main"
FloatLayout:
BigButton:
on_release: app.root.current = "notags"
text: "updating sequence"
pos_hint: {"x":0.25, "top": 0.4}
BigButton:
on_release: app.root.current = "sequence"
text: "sequence display"
pos_hint: {"x":0.25, "top": 0.7}
<AnotherScreen>:
name: "newgarage"
<NoTags>:
name: "notags"
SequenceBoxLayout_NoTag:
BackHomeWidget:
FloatLayout:
BigButton:
text: "Select Parts w/o Tags"
pos_hint: {"x":0.5, "top": 0.6}
background_normal: ''
background_color: (0.4,0.4,0.4,1)
<SequenceBoxLayout_NoEdits>:
box_share: box_share
ScrollView:
GridLayout:
id: box_share
cols: 1
size_hint_y: None
size_hint_x: 0.5
spacing: 5
padding: 130
height: self.minimum_height
canvas:
Color:
rgb: 0, 0, 0
Rectangle:
pos: self.pos
size: self.size
<SequenceBoxLayout_NoTag>:
box_share: box_share
ScrollView:
GridLayout:
id: box_share
cols: 1
size_hint_y: None
size_hint_x: 0.5
spacing: 5
padding: 130
height: self.minimum_height
canvas:
Color:
rgb: 0, 0, 0
Rectangle:
pos: self.pos
size: self.size
<SequenceScreen>:
name: "sequence"
SequenceBoxLayout_NoEdits:
id: updatedisplay
BackHomeWidget:
Credit:
Based on advice provided by #Tshirtman in the comments thread of the posted question...
Summary:
The problem with the code had to do with the fact that I had two different DictStore pointing to the same file, which was tripping up the communication between both classes.
The solution was to instead use only one DictStore and define that variable in the App class, then reference that particular variable in the child classes [using App.get_running_app()], like so:
Define config_file in App class:
class MainApp(App):
config_file = DictStore('conf2.dat')
def build(self):
return presentation
Reference App variable in child classes:
class SequenceBoxLayout_NoEdits(BoxLayout):
...
def __init__(self, **kwargs):
super(SequenceBoxLayout_NoEdits, self).__init__(**kwargs)
self.orientation = "vertical"
Clock.schedule_interval(self.create_button, 1)
def create_button(self, *args):
self.box_share.clear_widgets()
app = App.get_running_app()
...
for i in range(len(parts)):
...
if app.config_file.exists(id_):
btn_color = app.config_file[id_]["background_color"]
else:
app.config_file.put(id_, background_color=color)
...
...
class SequenceBoxLayout_NoTag(BoxLayout):
...
def __init__(self, **kwargs):
super(SequenceBoxLayout_NoTag, self).__init__(**kwargs)
self.orientation = "vertical"
Clock.schedule_once(self.create_button)
def create_button(self, *args):
...
app = App.get_running_app()
...
for i in range(len(parts)):
...
if app.config_file.exists(id_):
btn_color = app.config_file[id_]["background_color"]
else:
app.config_file.put(id_, background_color=color)
...
...
def update_buttons_notag(self, button):
app = App.get_running_app()
...
app.config_file.put(button.id, background_color=(0.86,0.54,0.04,1))
Clock has a schedule_interval method, which works much like the schedule_once one, but will be called every n seconds instead of just once after n seconds.
So you could certainly just change that call in __init__ and start the create_button by calling self.box_share.clear_widgets() to remove widgets from the previous call before re-creating them.
This might be a bit wasteful, if you find yourself recreating a lot of widgets even if nothing changed, so you could add some logic to first check if the data didn't change, or even if it did, just reuse the old buttons if possible.
box = self.box_share
old_buttons = box.children[:]
box.clear_widgets()
# [your logic about computing the list of parts]
for i, p in enumerate(parts): # this is much better than doing range(len(parts))
# [the logic to get the content of the button]
if old_buttons: # check there are still buttons in the list of old buttons
btn = old_buttons.pop()
else:
btn = Button(
background_normal='',
background_color=btn_color,
pos_hint={"x": 0, "top": top_button_share},
# etc, all the things that are common to all your buttons
# but really, hardcoding them like this is a bit painful,
# you should use a subclass of button so you can style it
# in a kv rule so it would apply to all of them directly
)
btn.id=id_
btn.text = "{}. {}".format(i+1, p)
btn.pos_hint["top"] = top_button_share
# re-apply any other property that might have changed for this part
box.add_widget(btn)
But this logic is quite a common one, actually, and there are other things you can do to improve things in even more situations, though that's quite some work.
Thankfully, you are not the first one to need such thing, and we have been blessed with the wonderful RecycleView, which automates all of this and more, you just need to feed it a data directory, and it'll create the necessary widgets to fill the visible part of the scrollview if there is enough widgets to warrant scrolling, and automatically update when data changes, and when you scroll to see different parts of the list. I encourage you to check it, yourself. but the end result would certainly be something like.
<PartButton#Button>:
id_: None
part: ''
text: '{}. {}'.format(self.id, self.part)
<SequencedBoxLayout#Recycleview>:
parts: self.get_parts()
viewclass: 'PartButton'
data:
[
{
id_: i,
part: part
} for i, p in enumerate(self.parts or [])
]
RecycleBoxLayout:
I want to call a method add_category_to_tree() from TreeCategory class, when pressing SAVE button in AddCategoryPopup class. However, I have problems how to reference to the TreeCategory instance, which is created in KV file.
I was trying to search solution, but nothing works. Currently i get AttributeError: 'super' object has no attribute '__getattr__' error.
How should I do this properly ? Thank you for help
class TreeCategory(TreeView):
def __init__(self, **kwargs):
super(TreeCategory, self).__init__(**kwargs)
def add_category_to_tree(self, name):
self.add_node(TreeViewLabel(text = name.upper()))
class AddCategoryPopup(Popup):
def save(self):
self.ids.tree.add_category_to_tree(self.ids.entry.text) # ????
db.adding_to_db('kategorie', 'nazwa', self.ids.entry.text)
self.dismiss()
def close(self):
self.dismiss()
class MainScreen(BoxLayout):
tree = ObjectProperty(None)
def add_category_button(self):
popup = AddCategoryPopup(title = 'Dodawanie nowej kategorii')
return popup.open()
class GuiCookBookApp(App):
def build(self):
self.title = "Książka kucharska"
return MainScreen()
if __name__ == "__main__":
db = DatabaseManager("cookbook.sqlite")
GuiCookBookApp().run()
KV file:
<AddCategoryPopup>:
BoxLayout:
orientation: 'vertical'
TextInput:
id: entry
multiline: False
hint_text: 'Podaj nazwę kategorii...'
BoxLayout:
orientation: 'horizontal'
Button:
text: 'SAVE'
on_press: root.save()
Button:
text: 'CANCEL'
on_press: root.close()
<MainScreen>:
orientation: "vertical"
display: entry
tree: tree
BoxLayout:
id: menu
size_hint_y: .1
Button:
text: 'Dodaj kategorię'
on_press: root.add_category_button()
BoxLayout:
id: recipe_view
orientation: "horizontal"
TreeCategory:
id: tree
hide_root: True
size_hint: .25, 1
With self.ids in Python you can only access the ids in KV from that particular class. So self.ids.tree is only possible inside the MainScreen class in Python not in the AddCategoryPopup class.
You could create an ObjectProperty 'topwidget' in your AddCategoryPopup rule and pass in the Main class when you instantiate the popup. Something like:
popup = AddCategoryPopup(topwidget=self)
Then in the 'save' method of your custom popup class you can do something like:
self.topwidget.tree...
You can do it quite a few ways. For instance you can put the .kv in your main .py file.
w = Builder.load_string('''
Widget:
height: self.width / 2. if self.disabled else self.width
x: self.y + 50
''')
https://kivy.org/docs/api-kivy.lang.builder.html
You can simply name the .kv file
guicookbookapp.kv
and leave it in the root directory of your project.
https://kivy.org/docs/examples/gen__application__app_with_kv__py.html
You can also add the following
from kivy.lang import Builder
Builder.load_file('guicookbookapp.kv')
Hopefully I understood your question correctly.
I am trying to update a label text from another class using its update method in Clock but I couldn't understand why its not updating the label properly .I have a sample code below :
gui_v9 = '''
#:import Clock kivy.clock.Clock
<Level_1>:
on_enter: self.EnterLevel_1()
<ScoreBar>:
time_Label: timelabel
GridLayout:
rows: 4
cols: 1
size: root.size
#Space away from border
padding: 2
spacing: 10
canvas:
Color:
rgba: 204/255.0, 204/255.0, 0/255.0, 1
Rectangle:
# self here refers to the widget i.e FloatLayout
pos: self.pos
size: self.size
Button:
text: 'Score'
size_hint: .5, .5
Label:
text: "Level 1"
Label:
text: "Time :"
id: timelabel
Button:
text: 'Mute'
'''
class ScoreBar(Widget):
time_Label = ObjectProperty(None)
def __init__(self):
super(ScoreBar, self).__init__()
class Level_1(Screen,Widget):
def __init__(self, **kwargs):
super(Level_1, self).__init__(**kwargs)
self.layout = GridLayout(cols=2,spacing=(10),padding=10)
def EnterLevel_1(self):
print "Hi This is EnterLevel_1 . Level One Gui work area "
scoreBar = ScoreBar()
Field = tama(speed=3)
self.layout.add_widget(Field)
self.layout.add_widget(scoreBar)
self.add_widget(self.layout)
Clock.schedule_interval(Field.update, 10.0/100)
#Field
class tama(Widget):
def __init__(self, speed=1 ):
super(tama, self).__init__()
self.speed = speed
self.id = "Field"
self.size = (800,600)
self.Extra = 200
print ScoreBar().time_Label.text
def update(self,dt):
print ScoreBar().time_Label.text
ScoreBar().time_Label.text ="cdfdfd"
# Create the screen manager
Builder.load_string(gui_v9)
sm = ScreenManager()
sm.add_widget(Level_1(name='level_1'))
class MyJB(App):
def build(self):
return sm
if __name__ == '__main__':
MyJB().run()
The issue is that you have lines like
print ScoreBar().time_Label.text
This doesn't tell you anything about the existing ScoreBar, it makes a new one and returns information about that.
From the tama, you could refer to self.parent.children[1] to access the one you actually originally added, or devise another way to access the reference.