I am having a strange issue when using Kivy's RecycleView. When trying to pass in a list of dictionaries using a custom widget I made as the viewclass it seems to create the correct number of widgets, however the actual values don't seem to get passed through, resulting in a correct number of "default" widgets. Here is a runnable example I created of the problem I am having:
main.py:
from kivy.app import App
import view
class MainApp(App):
def build(self):
return view.PostRV()
if __name__ == '__main__':
app = MainApp()
app.run()
main.kv:
<RVContainer>:
multiselect: True
touch_multiselect: True
height: self.minimum_height
cols: 1
default_size_hint: 1, None
default_size: None, dp(110)
size_hint_y: None
view.py:
from kivy.uix.recycleview import RecycleView
from kivy.uix.label import Label
from kivy.uix.button import Button
from kivy.uix.anchorlayout import AnchorLayout
from kivy.uix.gridlayout import GridLayout
from kivy.graphics import Color, RoundedRectangle
from kivy.core.window import Window
from kivy.properties import StringProperty
from kivy.uix.recyclegridlayout import RecycleGridLayout
class PostRV(RecycleView):
def __init__(self, **var_args):
super(PostRV, self).__init__(**var_args)
self.data = [
{'date': 'a date', 'time': 'a time', 'name': 'a name'},
{'date': 'another date', 'time': 'another time', 'name': 'another name'}
] # this data does not seem to pass through properly
self.add_widget(RVContainer())
self.size_hint = 1, 1
self.viewclass = Post
class RVContainer(RecycleGridLayout):
pass
# below this line is the custom widget "Post" which I split into multiple classes for easier control and clarity
class Post(AnchorLayout):
date = StringProperty('')
time = StringProperty('')
name = StringProperty('')
def __init__(self, **var_args):
super(Post, self).__init__(**var_args)
self.anchor_y = 'center'
self.anchor_x = 'center'
self.size_hint = 1, None
self.height = '110dp'
self.add_widget(PostContainer(date=self.date, time=self.time, name=self.name))
class PostContainer(GridLayout):
date = StringProperty('')
time = StringProperty('')
name = StringProperty('')
def __init__(self, **var_args):
super(PostContainer, self).__init__(**var_args)
self.cols = 2
self.padding = '12dp'
self.size_hint = (None, None)
self.width = Window.size[0] / 1.05
self.height = '100dp'
self.add_widget(PostShellOne(date=self.date, time=self.time, name=self.name))
self.add_widget(PostShellTwo())
self.bind(pos=self.update_rect, size=self.update_rect)
with self.canvas.before:
Color(1, 1, 1, .7)
self.rect = RoundedRectangle(size=self.size, pos=self.pos, radius=[10])
def update_rect(self, *args):
self.rect.pos = self.pos
self.rect.size = self.size
self.width = Window.size[0] / 1.05
class PostShellOne(GridLayout):
date = StringProperty('')
time = StringProperty('')
name = StringProperty('')
def __init__(self, **var_args):
super(PostShellOne, self).__init__(**var_args)
self.rows = 3
name_label = Label(text=self.name, color=(0, 0, 0, 1))
date_label = Label(text=self.date, color=(0, 0, 0, 1))
time_label = Label(text=self.time, color=(0, 0, 0, 1))
self.add_widget(name_label)
self.add_widget(time_label)
self.add_widget(date_label)
class PostShellTwo(Button):
def __init__(self, **var_args):
super(PostShellTwo, self).__init__(**var_args)
self.text = 'button'
self.background_color = (0, 0, 0, 0)
self.background_normal = ''
self.bind(pos=self.update_rect, size=self.update_rect)
with self.canvas.before:
Color(0, 0, 0, .4)
self.rect = RoundedRectangle(size=self.size, pos=self.pos, radius=[40])
def update_rect(self, *args):
self.rect.pos = self.pos
self.rect.size = self.size
Any help is appreciated, thank you!
The RecycleView works by creating instances of the viewclass (Post in your code), and then assigning the values from the data dictionary. So the __init__() methods of your Post classes create their child classes and pass in the current values of name, date, and time. But those values are still the default values of '' at that time. Then, when the actual values of name, date, and time get set for the Post instance, it is too late, and the values are not passed to the children of the Post instance.
A way to fix this is to use the kivy language, since it does automatic binding to the StringProperty variables. So, you can expand your main.kv to include the Post class and its children:
<RVContainer>:
multiselect: True
touch_multiselect: True
height: self.minimum_height
cols: 1
default_size_hint: 1, None
default_size: None, dp(110)
size_hint_y: None
<Post>:
anchor_y: 'center'
anchor_x: 'center'
size_hint: 1, None
height: '110dp'
PostContainer:
cols: 2
padding: '12dp'
size_hint: (None, None)
width: app.root.size[0] / 1.05
height: '100dp'
canvas:
Color:
rgba: (1, 1, 1, .7)
RoundedRectangle:
size: self.size
pos: self.pos
radius: [10]
PostShellOne:
rows: 3
Label:
text: root.name
color: 0,0,0,1
Label:
text: root.date
color: 0,0,0,1
Label:
text: root.time
color: 0,0,0,1
PostShellTwo:
text: 'button'
background_color: (0, 0, 0, 0)
background_normal: ''
canvas.before:
Color:
rgba: (0, 0, 0, .4)
RoundedRectangle:
size: self.size
pos: self.pos
radius: [40]
Note that the Labels in PostShellOne use the StringProperty values of the Post class, so they update automatically.
Then the Post classes can be defined more simply:
class Post(AnchorLayout):
date = StringProperty('')
time = StringProperty('')
name = StringProperty('')
class PostContainer(GridLayout):
pass
class PostShellOne(GridLayout):
pass
class PostShellTwo(Button):
pass