【发布时间】：2021-01-01 18:57:53
【问题描述】：
我正在制作一个计算器应用程序，我希望能够为每个屏幕使用单独的 kv 和 py 文件，我还没有找到任何关于此的文档或教程，the only answer I have found 没有给出代码示例所以我不确定如何实现它。此外，calc.kv 上的按钮通过在 root 中引用它来向 calc.py 发送回调，这样可能会导致问题，因为 root 是 screenmanager
如果您尝试从工具栏中打开计算器，它将返回此错误消息：
screen = self.get_screen(value)
File "C:\Python38\lib\site-packages\kivy\uix\screenmanager.py", line 1071, in get_screen
raise ScreenManagerException('No Screen with name "%s".' % name)
kivy.uix.screenmanager.ScreenManagerException: No Screen with name "calc".
代码如下：
calc.py
from logging import root
from kivymd.app import MDApp
from kivy.uix.widget import Widget
from kivy.core.window import Window
from kivy.properties import StringProperty
from kivy.lang import Builder
prev = ""
expression = ""
prox = ""
class calc(Widget):
pass
out = StringProperty('')
Window.size = (420, 200)
Window.minimum_width, Window.minimum_height = Window.size
def my_callback(self, inpt):
global prev
global expression
global prox
if inpt == "=":
prox = str(eval(expression))
self.out = prox
expression = ""
prev = prox
elif inpt == "ac":
expression = ""
prev = ""
prox = ""
self.out = expression
else:
expression = prev + inpt
prev = expression
self.out = expression
class calcApp(MDApp):
def build(self):
def press(text):
print("called: ", text)
return calc()
if __name__ == '__main__':
calcApp().run()
calc.kv
#:kivy 1.0.9
<calc>:
BoxLayout:
orientation: 'vertical'
cols: 2
size: root.width, root.height
MDLabel:
id: 'output'
text: str(root.out)
size_hint: 1, 0.2
halign: 'center'
GridLayout:
cols: 5
MDFlatButton:
text: '1'
on_press: root.my_callback(self.text)
MDFlatButton:
text: '2'
on_press: root.my_callback(self.text)
MDFlatButton:
text: '3'
on_press: root.my_callback(self.text)
MDFlatButton:
text: '-'
on_press: root.my_callback(self.text)
MDFlatButton:
text: 'ac'
on_press: root.my_callback(self.text)
MDFlatButton:
text: '4'
on_press: root.my_callback(self.text)
MDFlatButton:
text: '5'
on_press: root.my_callback(self.text)
MDFlatButton:
text: '6'
on_press: root.my_callback(self.text)
MDFlatButton:
text: '+'
on_press: root.my_callback(self.text)
MDFlatButton:
text: '('
on_press: root.my_callback(self.text)
MDFlatButton:
text: '7'
on_press: root.my_callback(self.text)
MDFlatButton:
text: '8'
on_press: root.my_callback(self.text)
MDFlatButton:
text: '9'
on_press: root.my_callback(self.text)
MDFlatButton:
text: '*'
on_press: root.my_callback(self.text)
MDFlatButton:
text: ')'
on_press: root.my_callback(self.text)
MDFlatButton:
text: '0'
on_press: root.my_callback(self.text)
MDFlatButton:
text: '.'
on_press: root.my_callback(self.text)
MDFlatButton:
text: '/'
on_press: root.my_callback(self.text)
MDFlatButton:
text: '**'
on_press: root.my_callback(self.text)
MDFlatButton:
text: '='
on_press: root.my_callback(self.text)
main.kv
#:kivy 1.0.9
#: include calc.kv
NavigationLayout:
id: nav_layout
ScreenManager:
Screen:
BoxLayout:
orientation: 'vertical'
MDToolbar:
title: app.title
elevation: 10
left_action_items: [['menu', lambda x: nav_drawer.set_state()]]
ScreenManager:
id: screen_manager
calculator:
MDNavigationDrawer:
id: nav_drawer
BoxLayout:
orientation: 'vertical'
padding: '8dp'
spacing: '8dp'
Image:
size_hint: None, None
size: '280dp', "200dp"
source: "logo.png"
ScrollView:
MDList:
OneLineIconListItem:
text: "calculadora"
on_release:
screen_manager.current = 'calc'
nav_drawer.set_state()
IconLeftWidget:
icon: 'view-dashboard'
main.py
import calc
from kivymd.app import MDApp
from kivy.lang import Builder
from kivy.uix.screenmanager import Screen, ScreenManager
class ScreenManager(ScreenManager):
pass
class MyApp(MDApp):
def build(self):
self.title = "calculadora"
self.theme_cls.primary_palette = "Green"
return Builder.load_file("main.kv")
MyApp().run()
提前致谢。
【问题讨论】：
-
您尚未使用名称
calc定义任何Screen。