how to add sub widget using kv?

[Michal]

Hello, Kivy is iteresting framework.
I am now solving issue how to change content of part of my root.
I have 2 classes
-------------------------------------------------------------------
class myBasicInfo(FloatLayout):
my_basic_info = ObjectProperty(None)
info_wid = Label() #object for login popup
info_label = Label(text='HHHH')

class myBase(FloatLayout):
basic_layout_wid = ObjectProperty(None) #object of layout
basic_layout_main_place_wid = ObjectProperty(None) #object of main
def do_action(self):
wid = myBasicInfo
self.basic_layout_main_place_wid.add_widget(wid.info_wid)

class myApp(App):
def build(self):
return myBase(info='Hello world')

if __name__ in ('__android__', '__main__'):
myApp().run()
--------------------------------------------------------------------------

and of course kv
--------------------------------------------------------------------------
#:kivy 1.0

<myBasicInfo>:
id: my_basic_info
info_wid: my_info_main

Label:
id: my_info_main
text: 'Not Connected'
height: 20

<myBase>:
id: my_widget
basic_layout_wid: my_basic_layout
basic_layout_main_place_wid: my_main_place

StackLayout:
id: my_basic_layout
anchor_x: 'left'
anchor_y: 'top'
Button:
size: (50, 20)
text: 'Home'
on_press: root.do_action();
StackLayout:
id: my_main_place

------------------------------------------------
What I am trying to do is, when I push a button HOME I want to put
content of myBasicInfo into my_main_place
I can do it by using property of class myBasicInfo.info_label:
def do_action(self):
wid = myBasicInfo
self.basic_layout_main_place_wid.add_widget(wid.info_label)

-----, but I want to use kv definition..
Any help???

[Michal]

With greate help from tshirtman (gabriel) it is solved..

to do it from KV 1. register widget by factory
------------main.kv
#:kivy 1.0
#:import SomeWidget main.SomeWidget

# rules for the widget
<SomeWidget>:
BoxLayout:
pos: root.pos
size: root.size
orientation: "vertical"
Label:
text: "hello"
Button:
text: "world"

# root
BoxLayout:
id: layout
Button:
text: "add"
on_press: layout.add_widget(SomeWidget())

------------main.py
#!/usr/bin/env python
from kivy.app import App
from kivy.uix.widget import Widget
from kivy.factory import Factory

class SomeWidget(Widget):
pass

Factory.register('SomeWidget', SomeWidget)

class Main(App):
pass

Main().run()

[Michal]

to do add it from py code... just one more linking

------main.py
#!/usr/bin/env python
from kivy.app import App
from kivy.uix.widget import Widget
from kivy.factory import Factory

from kivy.properties import ObjectProperty
from kivy.uix.boxlayout import BoxLayout

class SomeWidget(Widget):
pass

Factory.register('SomeWidget', SomeWidget)

class myOBDBase(BoxLayout):

layout_wid = ObjectProperty(None) #object of layout

def on_click(self):
print "Hello"
self.layout_wid.add_widget(SomeWidget())

class Main(App):
def build(self):
return myOBDBase(info='Hello world')

Main().run()

------main.kv
#:kivy 1.0

#:import SomeWidget main.SomeWidget

# rules for the widget
<SomeWidget>:
BoxLayout:
pos: root.pos
size: root.size
orientation: "vertical"
Label:
text: "hello"
Button:
text: "world"

# root
<myOBDBase>:
layout_wid: layout
BoxLayout:
id: layout

Button:
text: "add KV"
on_press: layout.add_widget(SomeWidget());
Button:
text: "add PY"
on_press: root.on_click()

[audiowerk]

Hi

i'm trying to do the same as explained, but in my case it doesn't work. I hope you can help me.

My python file:

from kivy.app import App

class AddwidgetApp(App):

    def build(self):

pass

AddwidgetApp().run()

and kv

#:kivy 1.0

#:import Button kivy.uix.button

BoxLayout:

    id: test

    Button:

        text: 'Add Device'

        on_press: test.add_widget(Button(text = 'Hello World'))

Thanks for any help!

[Noob Saibot]

When you pass build, you're pretty much telling your app not to load. Instead, you would subclass your BoxLayout widget, and have your AddWidgetApp return it during build. Like this:

from kivy.uix.boxlayout import BoxLayout
from kivy.uix.button import Button
from kivy.lang import Builder
from kivy.app import App

class MyMainWidget(BoxLayout):
    #Since there aren't any real callbacks in this widget, we pass.
    pass

class AddWidgetApp(App):

    def build(self):
        #You need to actually DO something in `build` for your app to work.
        app = MyMainWidget()
        return app

Builder.load_string("""
#Here, we design & define the parameters of `MyMainWidget`

<MyMainWidget>:


    id: test

    Button:
        text: 'Add Device'
        on_press: test.add_widget(Button(text='Hello World'))


""")

if __name__ == '__main__':
    AddWidgetApp().run()

Try running this and see if that works for you.

[audiowerk]

Hi,

thank you for your answer, but that is not true. The app works fine, exept that it breaks with the same error message yours does, when i press the button. Acutally we built the same app, but I defined everything in the kv file.

Here is your version's error message:

   File "_event.pyx", line 281, in kivy._event.EventDispatcher.dispatch (kivy\_event.c:4152)

   File "<string>", line 1, in <module>

 TypeError: 'module' object is not callable

And my version's error message:

   File "_event.pyx", line 281, in kivy._event.EventDispatcher.dispatch (kivy\_event.c:4152)

   File "...\addwidget.kv", line 1, in <module>

     #:kivy 1.0

 TypeError: 'module' object is not callable

This seems to be the same. What does this error Message mean? Thanks for any help!

[Noob Saibot]

Ah. That's because i forgot something important about importing classes from a module in kvlang.

If you add this to the beginning of your kvlang string like so...

Builder.load_string("""
#:import Button kivy.uix.button.Button

...

""")

...it works. Try it.

Good Luck

[audiowerk]

Hi,

my version works also. My mistake was that i wrote #:import Button kivy.uix.button instead of #:import Button kivy.uix.button.Button

Thanks for your helping me!

from kivy.lang import Builder

from kivy.app import App

class AddWidgetApp(App):

    def build(self):

        pass

Builder.load_string("""

#:import Button kivy.uix.button.Button

BoxLayout:

    id: test

    Button:

        text: 'Add Device'

[audiowerk]

In the next step I would like to to call a template such as

[MyButton@Button]:

    text: 'My Button'

is there any way to do that?

I also tried to do it by

class MyButton(Button):

pass

Factory.register('MyButton', cls=MyButton)

and

#:import MyButton main.MyButton

 in kv as described in the beginning. But if i try this method, I get the error message

 Unable to import package 'main.MyButton'

Thanks for any help!

[Noob Saibot]

You should read through the kvlang docs here. It explains Templates (and that they have since been depreciated. You should try using Dynamic Widgets instead). Let us know if you have further questions.

[audiowerk]

Thank's for your advice. I changed to Dynamic classes. Nevertheless I get the same results as described.

Question 1:

When i use

<MyButton@Button>:

    text: 'My Button'

and call it with

                Button:

                    text: 'Add Button'

                    on_press: test.add_widget(MyButton(text='Hello World'))

I get

 NameError: name 'MyButton' is not defined

Question 2:

[Noob Saibot]

Question 1 & Question 2:

In kvlang, the convention with binding is... 

property : python code # with `id`s

If you had directly added MyButton to a Widget, there'd be no problem; but because you're using python to bind it in a callback, you get a NameError because MyButton isn't defined in python. It's better practice to do all of your DESIGNING in kvlang, and your CALLBACKS in python.

Do something like this instead:

class MyButton(Button):
    pass

class Test(BoxLayout):

    def some_callback(self, *args):
        self.add_widget(MyButton())

############################################

<MyButton>:
    text: 'My Button'

<Test>:
    btn: btn_id

    Button:
        id: btn_id
        text: 'Add Button'
        on_press: root.some_callback(*args)

This way, you separate responsibilities. If there's a problem with how the widgets are being displayed, check the kvlang. If there's a problem with how the widgets are interacting with each other, touch, etc., check the python. Simpler, no?

[Spencer Perkins]

I'm missing something here. No matter where I try and stick the factory.register(), my CharactersScreen class isn't getting recognized. What am I doing wrong?

from kivy.app import App

from kivy.uix.screenmanager import ScreenManager, Screen

from kivy.uix.textinput import TextInput

from kivy.uix.dropdown import DropDown

from kivy.uix.button import Button

from kivy.properties import NumericProperty, StringProperty

from kivy.lang import Builder

from kivy.storage.jsonstore import JsonStore

from os.path import join

from kivy.uix.widget import Widget

from kivy.factory import Factory

Builder.load_string('''

#:import random random.random

#:import SlideTransition kivy.uix.screenmanager.SlideTransition

#:import NoTransition kivy.uix.screenmanager.NoTransition

#:import CharactersScreen main.CharactersScreen

<BasicScreen>:

    hue: random()

    canvas:

        Color:

            hsv: self.hue, .5, .3

        Rectangle:

            size: self.size

    Label:

        font_size: 42

        text: root.name

        pos_hint: {'center_y': 0.95}

    BoxLayout:

        size_hint: None, 1

        pos_hint: {'center_y': .5}

        orientation: 'vertical'

        Button:

            text: 'Characters!'

            on_release: root.manager.current = 'Characters'

        Button:

            text: 'Identity'

            on_release: root.manager.current = 'Identity'

        Button:

            text: 'Abilities'

            on_release: root.manager.current = 'Abilities'

        Button:

            text: 'Attacks'

            on_release: root.manager.current = 'Attacks'

        Button:

            text: 'Health'

            on_release: root.manager.current = 'Health'

        Button:

            text: 'Powers'

            on_release: root.manager.current = 'Powers'

        Button:

            text: 'Skills'

            on_release: root.manager.current = 'Skills'

        Button:

            text: 'Feats'

            on_release: root.manager.current = 'Feats'

        Button:

            text: 'Equipment'

            on_release: root.manager.current = 'Equipment'

        Button:

            text: 'Rituals'

            on_release: root.manager.current = 'Rituals'

        Button:

            text: 'Notes'

            on_release: root.manager.current = 'Notes'

<CharactersScreen>:

    Button:

        text: 'Save'

        pos_hint: {'center_x': 0.95, 'center_y': .95}

        size_hint: .1, .1

        on_release: root.save()

    Button:

        text: 'New'

        pos_hint: {'center_x': 0.85, 'center_y': .95}

        size_hint: .1, .1

        on_release: self.createNew()

    Button:

        text: '+'

        size_hint: .05, .05

        pos_hint: {'center_x': 0.34, 'center_y': 0.8}

        on_release: root.createNew()

    TextInput:

        id: newchar

        text: 'enter name here'

        multiline: False

        pos_hint: {'center_x': 0.5, 'center_y': 0.8}

        size_hint: 0.25, None

        height: 30

    StackLayout:

        id: chargrid

        size_hint: .5,.5

        pos_hint: {'center_x': .5,'center_y': .5}

        

    

<IdentityScreen>:

    BoxLayout:

        size_hint: .25, .75

        pos_hint: {'center_x': 0.6,'center_y': .5}

        orientation: 'vertical'

        Button:

            text: 'Name'

            on_release: root.yopo()

        TextInput:

            id: charname

            text: ''

            multiline: False

        Label:

            text: 'Level'

        TextInput:

            id: charlevel

            text: ''

            multiline: False

        Label:

            text: 'XP'

        TextInput:

            id: charxp

            text: ''

            multiline: False

        Label:

            text: 'Race'

        TextInput:

            id: charrace

            text: ''

            multiline: False

        Label:

            text: 'Class'

        TextInput:

            id: charclass

            text: ''

            multiline: False

        Label:

            text: 'Paragon'

        TextInput:

            id: charparagon

            text: ''

            multiline: False

        Label:

            text: 'Epic'

        TextInput:

            id: charepic

            text: ''

            multiline: False

        Label:

            text: 'Misc.'

        TextInput:

            id: charmisc

            text: ''

            multiline: False

<AbilitiesScreen>:

    GridLayout:

        cols: 5

        size_hint: .3, .5

        pos_hint: {'center_x': .5,'center_y': .5}

        Label:

            text: 'Abil'

        Label:

            text: 'Score'

        Label:

            text: 'Mod'

        Label:

            text: 'Defense'

        Label:

            text: 'Score'

        Label:

            text: 'Str'

        TextInput:

            text: ''

            multiline: False

        Label:

            text: '0'

        Label:

            text: 'AC'

        Label:

            text: '15'

        Label:

            text: 'Con'

        TextInput:

            text: ''

            multiline: False

        Label:

            text: '0'

        Label:

            text: 'AC'

        Label:

            text: '15'

        Label:

            text: 'Dex'

        TextInput:

            text: ''

            multiline: False

        Label:

            text: '0'

        Label:

            text: 'AC'

        Label:

            text: '15'

        Label:

            text: 'Int'

        TextInput:

            text: ''

            multiline: False

        Label:

            text: '0'

        Label:

            text: 'AC'

        Label:

            text: '15'

        Label:

            text: 'Wis'

        TextInput:

            text: ''

            multiline: False

        Label:

            text: '0'

        Label:

            text: 'AC'

        Label:

            text: '15'

        Label:

            text: 'Cha'

        TextInput:

            text: ''

            multiline: False

        Label:

            text: '0'

        Label:

            text: 'AC'

        Label:

            text: '15'

ScreenManager:

    id: screen_manager

    CharactersScreen:

        id: characters_screen

    

''')

class BasicScreen(Screen):

    hue = NumericProperty(0)

    def save(self):

        data_dir = App().user_data_dir

        store = JsonStore(join(data_dir, 'dandy.json'))

        cname = self.ids.charname.text

        crace = self.ids.charrace.text

        store.put(cname,race=crace)

class IdentityScreen(BasicScreen):

    pass

class CharactersScreen(BasicScreen):

    def loadem(self):

        data_dir = App().user_data_dir

        store = JsonStore(join(data_dir, 'dandy.json'))

        chars = store.keys()

        for i in range(len(chars)):

            self.add_button(chars[i])

    def loadCharData(self,char):

        data_dir = App().user_data_dir

        store = JsonStore(join(data_dir, 'dandy.json'))

        self.ids.charname.text = 'Dave'

        self.ids.charrace.text = 'Human'

    def createNew(self):

        data_dir = App().user_data_dir

        store = JsonStore(join(data_dir, 'dandy.json'))

        store.put(self.ids.newchar.text)

        self.add_button(self.ids.newchar.text)

    def add_button(self,name):

        btn = Button(text=name)

        self.ids.chargrid.add_widget(btn)

        btn.bind(on_press=self.callback)

    def callback(self,instance):

        self.loadCharData('%s')

        

class AbilitiesScreen(BasicScreen):

    pass

Factory.register('CharactersScreen', CharactersScreen)

class ScreenManagerApp(App):

    title = 'Dandy'

    def build(self):

        pages = ['Attacks','Health','Powers','Skills','Feats','Equipment','Rituals','Notes']

        root = ScreenManager()

        #charscreen = CharactersScreen(name='Characters')

        #Factory.register('CharactersScreen', cls=CharactersScreen)

        #idscreen = IdentityScreen(name='Identity')

        #root.add_widget(charscreen)

        #root.add_widget(idscreen)

        #root.add_widget(AbilitiesScreen(name='Abilities'))

        for i in range(len(pages)):

            root.add_widget(BasicScreen(name=pages[i]))

        #charscreen.loadem()

        return root

if __name__ == '__main__':

    ScreenManagerApp().run()

[Spencer Perkins]

figured it out. alls I had to do was registers AFTER the class but BEFORE the kivy file loaded. loving kivy so far

[ZenCODE]

Nice. Thanks for posting back. And welcome to the Kivy lovers club. Kivy For The Win! :-)

[Spencer Perkins]

thanks, I'm sure I'll be around here a lot

[Ezra Calubsing]

Thank you for this post, it help me.

can i ask one more thing.

how can i limit how many widget can i add.

currently the code that i created base from Michal, I can add widget endlessly.

how can i limit it to 5.

Thank you.

[ZenCODE]

if len(widget.children) < 5:
     # Do crazy stuff
     pass
else:
     # Behave!
    pass

It's not Kivy's job to control stuff like this. If you want to do silly things, that's your right...:-)

[ZenCODE]

Ps. Oops, sorry, I did not mean to imply anyone is silly, just wanted to point out a framework should allow the programmer to do what they want (within reason)