在 Kivy 中，如何在具有多个屏幕的应用程序的特定屏幕上添加 CircularProgressBar？

Question

我正在尝试开发一个以圆形进度条的形式显示某些数据的 Kivy 应用程序。我通过这个链接了解了循环进度条：How to make circular progress bar in kivy? 但是，我无法将此小部件添加到特定屏幕上。

我希望将小部件嵌入到我的屏幕上并包含一些其他小部件。我曾尝试制作一个单独的 .kv 文件，但它也不起作用。这是我的代码。我希望在我的主页中有循环进度条。

from kivy.app import App
from kivy.uix.progressbar import ProgressBar
from kivy.core.text import Label as CoreLabel
from kivy.lang.builder import Builder
from kivy.graphics import Color, Ellipse, Rectangle
from kivy.clock import Clock
from kivy.uix.screenmanager import Screen, ScreenManager

Builder.load_string('''
<HomePage>:
    FloatLayout:
        canvas.before:
            Rectangle:
                # self here refers to the widget i.e BoxLayout
                pos: self.pos
                size: self.size
        CircularProgressBar:
            size_hint:(None,None)
            height:400
            width:400
            max:80
    ''')


class HomePage(Screen):
    pass
class CircularProgressBar(ProgressBar):
    def __init__(self,**kwargs):
        super(CircularProgressBar,self).__init__(**kwargs)
        self.thickness = 40
        self.label = CoreLabel(text="0",font_size=self.thickness)
        self.texture_size= None
        self.refresh_text()
        self.draw()
    def draw(self):
        with self.canvas:
            self.canvas.clear()
            #No progress
            Color(0.26,0.26,0.26)
            Ellipse(pos=self.pos, size=self.size)
            #Progress Circle
            Color(1,0,0)
            Ellipse(pos=self.pos,size=self.size,angle_end=0.5*360)#will be replaced with necessary data
            #Inner Circle
            Color(0,0,0)
            Ellipse(pos=(self.pos[0] + self.thickness / 2, self.pos[1] + self.thickness / 2),size=(self.size[0] - self.thickness, self.size[1] - self.thickness))
            #Inner text
            Color(1, 1, 1, 1)
            Rectangle(texture=self.label.texture,size=self.texture_size,pos=(self.size[0]/2-self.texture_size[0]/2,self.size[1]/2 - self.texture_size[1]/2))
            self.label.text = str(int(0.5*100))
    def refresh_text(self):
        self.label.refresh()
        self.texture_size=list(self.label.texture.size)
    def set_value(self, value):
        self.value = value
        self.label.text = str(int(0.5*100))
        self.refresh_text()
        self.draw()

sm = ScreenManager()
sm.add_widget(HomePage(name="HomePage"))

class HealthTrackingSystem(App):
    def animate(self,dt):
        if self.root.value<80:
            self.root.set_value(self.root.set_value+1)
        else:
            self.root.set_value(0)

    def build(self):
        Clock.schedule_interval(self.animate, 0.1)
        return sm

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

我在运行代码时遇到以下错误：

 File "HealthTrackingSystem.py", line 70, in animate
 if self.root.value<80
 'ScreenManager' object has no attribute 'value'

Answer 1

在您的代码中，self.root 是您在 build 方法中返回的 ScreenManager。您可能希望将id 添加到您的CircularProgressBar:（在kv 中），然后使用它来引用您的CircularProgressBar。

这是它的样子（包括使CircularProgressBar 工作的编辑）：

from kivy.app import App
from kivy.uix.progressbar import ProgressBar
from kivy.core.text import Label as CoreLabel
from kivy.lang.builder import Builder
from kivy.graphics import Color, Ellipse, Rectangle
from kivy.clock import Clock
from kivy.uix.screenmanager import Screen, ScreenManager

Builder.load_string('''
<HomePage>:
    FloatLayout:
        canvas.before:
            Rectangle:
                # self here refers to the widget i.e BoxLayout
                pos: self.pos
                size: self.size
        CircularProgressBar:
            id: cp
            size_hint:(None,None)
            height:400
            width:400
            max:80
    ''')


class HomePage(Screen):
    pass
class CircularProgressBar(ProgressBar):
    def __init__(self,**kwargs):
        super(CircularProgressBar,self).__init__(**kwargs)
        self.thickness = 40
        self.label = CoreLabel(text="0",font_size=self.thickness)
        self.texture_size= None
        self.refresh_text()
        self.draw()
    def draw(self):
        with self.canvas:
            self.canvas.clear()
            #No progress
            Color(0.26,0.26,0.26)
            Ellipse(pos=self.pos, size=self.size)
            #Progress Circle
            Color(1,0,0)
            Ellipse(pos=self.pos,size=self.size,angle_end=(self.value/100.0)*360)#will be replaced with necessary data
            #Inner Circle
            Color(0,0,0)
            Ellipse(pos=(self.pos[0] + self.thickness / 2, self.pos[1] + self.thickness / 2),size=(self.size[0] - self.thickness, self.size[1] - self.thickness))
            #Inner text
            Color(1, 1, 1, 1)
            Rectangle(texture=self.label.texture,size=self.texture_size,pos=(self.size[0]/2-self.texture_size[0]/2,self.size[1]/2 - self.texture_size[1]/2))
            self.label.text = str(int(self.value))
    def refresh_text(self):
        self.label.refresh()
        self.texture_size=list(self.label.texture.size)
    def set_value(self, value):
        self.value = value
        self.label.text = str(int(self.value))
        self.refresh_text()
        self.draw()

sm = ScreenManager()
sm.add_widget(HomePage(name="HomePage"))

class HealthTrackingSystem(App):
    def animate(self,dt):
        circProgressBar = self.root.get_screen('HomePage').ids.cp
        if circProgressBar.value<80:
            circProgressBar.set_value(circProgressBar.value+1)
        else:
            circProgressBar.set_value(0)

    def build(self):
        Clock.schedule_interval(self.animate, 0.1)
        return sm

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