Kivy RecycleView 进入屏幕后不显示数据
Kivy RecycleView not showing data after moving into a screen
我修改了一个 Kivy RecycleView 示例并将其放入带有菜单的屏幕中，但现在它显示的是空页面而不是数据。我怀疑根已更改，但我无法将 RecycleView 连接到正确的源。
老实说，我认为我必须更多地学习如何在不同对象之间正确 link。
我修改后的版本有问题：
from kivy.app import App
from kivy.properties import ObjectProperty, StringProperty, NumericProperty, ListProperty
from kivy.uix.recycleview.views import RecycleDataViewBehavior
from kivy.uix.boxlayout import BoxLayout
from kivy.lang.builder import Builder
from kivy.uix.screenmanager import Screen, ScreenManager
KV = """
<SomeMenu_ActionBar@ActionBar>:
ActionView:
id: ActionView
HiddenIcon_ActionPrevious:
ActionButton:
text: 'Stop'
on_release: app.stop()
<HiddenIcon_ActionPrevious@ActionPrevious>:
<MainBox>:
orientation: 'vertical'
canvas.before:
Color:
rgb: .6, .6, .6
Rectangle:
pos: self.pos
size: self.size
# source: 'data/background.png'
MyManager:
id: sm
RVScreen:
id: rvscreen
SomeMenu_ActionBar:
id: ActionBar
<RecycleItem>:
orientation: 'horizontal'
Label:
text: root.label_text
TextInput:
text: root.input_text
on_text: root.set_text(self.text)
RecycleView:
data: app.data
viewclass: 'RecycleItem'
RecycleBoxLayout:
spacing: 10
default_size: None, dp(80)
default_size_hint: 1, None
orientation: 'vertical'
size_hint_y: None
height: self.minimum_height
<RVScreen>:
id: "rvscreen"
BoxLayout:
orientation: "vertical"
RecycleView:
Button:
text: 'Previous screen'
size_hint: None, None
size: 150, 50
on_release: root.manager.current = root.manager.previous()
"""
class RecycleItem(RecycleDataViewBehavior, BoxLayout):
owner = ObjectProperty()
index = NumericProperty(0)
input_text = StringProperty()
label_text = StringProperty()
def set_text(self, text):
if self.owner is not None:
self.owner.data[self.index]['input_text'] = text
def refresh_view_attrs(self, rv, index, data):
self.index = index
return super(RecycleItem, self).refresh_view_attrs(rv, index, data)
class MainBox(BoxLayout):
"""Mainbox under MainApp
It contains the ScreenManager
"""
pass
class RVScreen(Screen):
pass
class MyManager(ScreenManager):
"""The screen manager that handles app screens
"""
pass
class Test(App):
data = ListProperty()
def build(self):
self.data = [{'label_text': "Label "+str(x), "input_text": "Input "+str(x), 'owner': self} for x in range(20)]
Builder.load_string(KV)
return MainBox()
Test().run()
原始工作示例：
from kivy.app import App
from kivy.properties import ObjectProperty, StringProperty, NumericProperty, ListProperty
from kivy.uix.recycleview.views import RecycleDataViewBehavior
from kivy.uix.boxlayout import BoxLayout
from kivy.lang.builder import Builder
KV = """
<RecycleItem>:
orientation: 'horizontal'
Label:
text: root.label_text
TextInput:
text: root.input_text
on_text: root.set_text(self.text)
RecycleView:
data: app.data
viewclass: 'RecycleItem'
RecycleBoxLayout:
spacing: 10
default_size: None, dp(80)
default_size_hint: 1, None
orientation: 'vertical'
size_hint_y: None
height: self.minimum_height
<RVScreen>:
BoxLayout:
orientation: "vertical"
RecycleView:
Button:
text: 'Previous screen'
size_hint: None, None
size: 150, 50
on_release: root.manager.current = root.manager.previous()
"""
class RecycleItem(RecycleDataViewBehavior, BoxLayout):
owner = ObjectProperty()
index = NumericProperty(0)
input_text = StringProperty()
label_text = StringProperty()
def set_text(self, text):
if self.owner is not None:
self.owner.data[self.index]['input_text'] = text
def refresh_view_attrs(self, rv, index, data):
self.index = index
return super(RecycleItem, self).refresh_view_attrs(rv, index, data)
class Test(App):
data = ListProperty()
def build(self):
self.data = [{'label_text': "Label "+str(x), "input_text": "Input "+str(x), 'owner': self} for x in range(20)]
return Builder.load_string(KV)
Test().run()
您可以通过多种方式定义 root 小部件。
如果您有 build method in the App's subclass and it returns some Widget, it will be set as the root 小部件。或者您可以通过将 root 加载到 kv-rule 等
在这种情况下，在您的 kv-rule 中，您将 RecycleView 定义为 root 小部件，但您没有在 build 中使用它来将其设置为 root.
与此同时，您从方法 build 返回了 MainBox，因此它将用作 root 小部件。您再次在此处加载了 kv-rule，因此设计等将应用于此根小部件。
现在为了将 RecycleView 添加到 RVScreen（如您在 中提到的）并将 MainBox 设置为 root 小部件（如您所做的已经）你可以修改你的 kvlang 如下：
<SomeMenu_ActionBar@ActionBar>:
ActionView:
id: ActionView
HiddenIcon_ActionPrevious:
ActionButton:
text: 'Stop'
on_release: app.stop()
<HiddenIcon_ActionPrevious@ActionPrevious>:
<MainBox>:
orientation: 'vertical'
canvas.before:
Color:
rgb: .6, .6, .6
Rectangle:
pos: self.pos
size: self.size
# source: 'data/background.png'
MyManager:
id: sm
RVScreen:
id: rvscreen
SomeMenu_ActionBar:
id: ActionBar
<RecycleItem>:
orientation: 'horizontal'
Label:
text: root.label_text
TextInput:
text: root.input_text
on_text: root.set_text(self.text)
<RVScreen>:
id: "rvscreen"
BoxLayout:
orientation: "vertical"
RecycleView:
data: app.data
viewclass: 'RecycleItem'
RecycleBoxLayout:
spacing: 10
default_size: None, dp(80)
default_size_hint: 1, None
orientation: 'vertical'
size_hint_y: None
height: self.minimum_height
Button:
text: 'Previous screen'
size_hint: None, None
size: 150, 50
on_release: root.manager.current = root.manager.previous()
我修改了一个 Kivy RecycleView 示例并将其放入带有菜单的屏幕中，但现在它显示的是空页面而不是数据。我怀疑根已更改，但我无法将 RecycleView 连接到正确的源。
老实说，我认为我必须更多地学习如何在不同对象之间正确 link。
我修改后的版本有问题：
from kivy.app import App
from kivy.properties import ObjectProperty, StringProperty, NumericProperty, ListProperty
from kivy.uix.recycleview.views import RecycleDataViewBehavior
from kivy.uix.boxlayout import BoxLayout
from kivy.lang.builder import Builder
from kivy.uix.screenmanager import Screen, ScreenManager
KV = """
<SomeMenu_ActionBar@ActionBar>:
ActionView:
id: ActionView
HiddenIcon_ActionPrevious:
ActionButton:
text: 'Stop'
on_release: app.stop()
<HiddenIcon_ActionPrevious@ActionPrevious>:
<MainBox>:
orientation: 'vertical'
canvas.before:
Color:
rgb: .6, .6, .6
Rectangle:
pos: self.pos
size: self.size
# source: 'data/background.png'
MyManager:
id: sm
RVScreen:
id: rvscreen
SomeMenu_ActionBar:
id: ActionBar
<RecycleItem>:
orientation: 'horizontal'
Label:
text: root.label_text
TextInput:
text: root.input_text
on_text: root.set_text(self.text)
RecycleView:
data: app.data
viewclass: 'RecycleItem'
RecycleBoxLayout:
spacing: 10
default_size: None, dp(80)
default_size_hint: 1, None
orientation: 'vertical'
size_hint_y: None
height: self.minimum_height
<RVScreen>:
id: "rvscreen"
BoxLayout:
orientation: "vertical"
RecycleView:
Button:
text: 'Previous screen'
size_hint: None, None
size: 150, 50
on_release: root.manager.current = root.manager.previous()
"""
class RecycleItem(RecycleDataViewBehavior, BoxLayout):
owner = ObjectProperty()
index = NumericProperty(0)
input_text = StringProperty()
label_text = StringProperty()
def set_text(self, text):
if self.owner is not None:
self.owner.data[self.index]['input_text'] = text
def refresh_view_attrs(self, rv, index, data):
self.index = index
return super(RecycleItem, self).refresh_view_attrs(rv, index, data)
class MainBox(BoxLayout):
"""Mainbox under MainApp
It contains the ScreenManager
"""
pass
class RVScreen(Screen):
pass
class MyManager(ScreenManager):
"""The screen manager that handles app screens
"""
pass
class Test(App):
data = ListProperty()
def build(self):
self.data = [{'label_text': "Label "+str(x), "input_text": "Input "+str(x), 'owner': self} for x in range(20)]
Builder.load_string(KV)
return MainBox()
Test().run()
原始工作示例：
from kivy.app import App
from kivy.properties import ObjectProperty, StringProperty, NumericProperty, ListProperty
from kivy.uix.recycleview.views import RecycleDataViewBehavior
from kivy.uix.boxlayout import BoxLayout
from kivy.lang.builder import Builder
KV = """
<RecycleItem>:
orientation: 'horizontal'
Label:
text: root.label_text
TextInput:
text: root.input_text
on_text: root.set_text(self.text)
RecycleView:
data: app.data
viewclass: 'RecycleItem'
RecycleBoxLayout:
spacing: 10
default_size: None, dp(80)
default_size_hint: 1, None
orientation: 'vertical'
size_hint_y: None
height: self.minimum_height
<RVScreen>:
BoxLayout:
orientation: "vertical"
RecycleView:
Button:
text: 'Previous screen'
size_hint: None, None
size: 150, 50
on_release: root.manager.current = root.manager.previous()
"""
class RecycleItem(RecycleDataViewBehavior, BoxLayout):
owner = ObjectProperty()
index = NumericProperty(0)
input_text = StringProperty()
label_text = StringProperty()
def set_text(self, text):
if self.owner is not None:
self.owner.data[self.index]['input_text'] = text
def refresh_view_attrs(self, rv, index, data):
self.index = index
return super(RecycleItem, self).refresh_view_attrs(rv, index, data)
class Test(App):
data = ListProperty()
def build(self):
self.data = [{'label_text': "Label "+str(x), "input_text": "Input "+str(x), 'owner': self} for x in range(20)]
return Builder.load_string(KV)
Test().run()
您可以通过多种方式定义 root 小部件。
如果您有 build method in the App's subclass and it returns some Widget, it will be set as the root 小部件。或者您可以通过将 root 加载到 kv-rule 等
在这种情况下，在您的 kv-rule 中，您将 RecycleView 定义为 root 小部件，但您没有在 build 中使用它来将其设置为 root.
与此同时，您从方法 build 返回了 MainBox，因此它将用作 root 小部件。您再次在此处加载了 kv-rule，因此设计等将应用于此根小部件。
现在为了将 RecycleView 添加到 RVScreen（如您在 MainBox 设置为 root 小部件（如您所做的已经）你可以修改你的 kvlang 如下：
<SomeMenu_ActionBar@ActionBar>:
ActionView:
id: ActionView
HiddenIcon_ActionPrevious:
ActionButton:
text: 'Stop'
on_release: app.stop()
<HiddenIcon_ActionPrevious@ActionPrevious>:
<MainBox>:
orientation: 'vertical'
canvas.before:
Color:
rgb: .6, .6, .6
Rectangle:
pos: self.pos
size: self.size
# source: 'data/background.png'
MyManager:
id: sm
RVScreen:
id: rvscreen
SomeMenu_ActionBar:
id: ActionBar
<RecycleItem>:
orientation: 'horizontal'
Label:
text: root.label_text
TextInput:
text: root.input_text
on_text: root.set_text(self.text)
<RVScreen>:
id: "rvscreen"
BoxLayout:
orientation: "vertical"
RecycleView:
data: app.data
viewclass: 'RecycleItem'
RecycleBoxLayout:
spacing: 10
default_size: None, dp(80)
default_size_hint: 1, None
orientation: 'vertical'
size_hint_y: None
height: self.minimum_height
Button:
text: 'Previous screen'
size_hint: None, None
size: 150, 50
on_release: root.manager.current = root.manager.previous()