Kivy recycleview未更新时钟调用函数

Question

我的应用程序在recycleview中有一个计时器作为数据，它将每秒更新以更改计时器的文本。所以我用Clock每隔一秒调用timer_update函数来更新时间。

问题是，在终端上打印时，计时器文本会更新，但在应用程序屏幕上不会更新。

这是我的代码：

import datetime
from kivy.clock import Clock
from kivy.lang import Builder
from kivymd.app import MDApp
from kivy.properties import StringProperty
from kivymd.uix.boxlayout import MDBoxLayout
from kivy.uix.screenmanager import ScreenManager, Screen

Builder.load_string( '''
<Timer>:
orientarion: 'vertical'
md_bg_color: 0, 0, 1, 1

MDLabel:
text: root.text
color: 1,1,1,1
halign: 'center'

<MyLayout>:
MDBoxLayout:
orientation: 'vertical'

RecycleView:
id: rv
key_viewclass: 'viewclass'
key_size: 'height'
effect_cls: 'ScrollEffect'

RecycleBoxLayout:
padding: dp(10)
size_hint_y: None
default_size: None, dp(60)
default_size_hint: 1, None
height: self.minimum_height
orientation: 'vertical'

''')
class Sm(ScreenManager):
pass


class Timer(MDBoxLayout):
text = StringProperty()

class MyLayout(Screen):

def on_enter(self):
self.add_timer()
Clock.schedule_interval(self.update_timer, 1)
def update_timer(self, dt):
self.ids.rv.data[0]['text'] = str(datetime.datetime.now())
print(self.ids.rv.data[0]['text'])

def add_timer(self):
self.ids.rv.data.append(
{
"viewclass": "Timer",
"text": str(datetime.datetime.now()),
"callback": lambda x: x,
}
)

class MyApp(MDApp):

def build(self):
sm = Sm()
sm.add_widget(MyLayout())
return sm

MyApp().run()

Answer 1

如果在更新数据后调用self.ids.rv.refresh_from_data()，就可以了。

完整示例：

import datetime
from kivy.clock import Clock
from kivy.lang import Builder
from kivymd.app import MDApp
from kivy.properties import StringProperty
from kivymd.uix.boxlayout import MDBoxLayout
from kivy.uix.screenmanager import ScreenManager, Screen

Builder.load_string( '''
<Timer>:
orientarion: 'vertical'
md_bg_color: 0, 0, 1, 1

MDLabel:
text: root.text
color: 1,1,1,1
halign: 'center'

<MyLayout>:
MDBoxLayout:
orientation: 'vertical'

RecycleView:
id: rv
key_viewclass: 'viewclass'
key_size: 'height'
effect_cls: 'ScrollEffect'

RecycleBoxLayout:
padding: dp(10)
size_hint_y: None
default_size: None, dp(60)
default_size_hint: 1, None
height: self.minimum_height
orientation: 'vertical'

''')
class Sm(ScreenManager):
pass


class Timer(MDBoxLayout):
text = StringProperty()

class MyLayout(Screen):

def on_enter(self):
self.add_timer()
Clock.schedule_interval(self.update_timer, 1)
def update_timer(self, dt):
self.ids.rv.data[0]['text'] = str(datetime.datetime.now())
self.ids.rv.refresh_from_data()
print(self.ids.rv.data[0]['text'])

def add_timer(self):
self.ids.rv.data.append(
{
"viewclass": "Timer",
"text": str(datetime.datetime.now()),
"callback": lambda x: x,
}
)
class MyApp(MDApp):

def build(self):
sm = Sm()
sm.add_widget(MyLayout())
return sm

MyApp().run()