如何在kivymd屏幕之间传递参数?

1tuwyuhd  于 2021-08-20  发布在  Java
关注(0)|答案(1)|浏览(438)

当从第一个屏幕转到第二个屏幕时,我想传递一个变量作为参数,以便kivymd可以从存储在excel文件中的文本更新第二个屏幕。以下是我的应用程序功能的框架:
用户通过kivymd中的导航抽屉到达屏幕1,屏幕1在两个小型可点击MD卡上向用户显示两个选项:
“将文本更改为1”
“将文本更改为2”
单击其中一个后,应用程序切换到屏幕2,屏幕上只有一张大MD卡,此MD卡上的文本应更改以反映用户选择的选项。
然而,kivy正在从excel文件中提取要显示在大MD卡上的文本。我想从屏幕1传递到屏幕2的变量只是一个数字(1或2),它将告诉kivy它应该从excel文件中的哪一行提取文本
如果用户单击“将文本更改为1”,则第一个屏幕应通过“1”作为参数 row_x 到功能 def change_text() (请参见screen 2.py),以便excel第1行中的文本可以显示在第二个屏幕上。我怎样才能做到这一点?
我一共有4个文件;3个是.py文件(一个用于主应用程序,一个用于屏幕1,一个用于屏幕2)和excel文件
注:在下面的代码中,屏幕1和2分别称为元素1和2
main.py:

from kivy.lang import Builder
from kivy.uix.boxlayout import BoxLayout
from kivy.properties import ObjectProperty
from kivymd.app import MDApp
from element_1 import element_1_screen
from element_2 import element_2_screen

MainNavigation = '''
<ContentNavigationDrawer>:
    ScrollView:
        MDList:
            OneLineListItem:
                text: 'Go to Element 1'
                on_press:
                    root.nav_drawer.set_state("close")
                    root.screen_manager.current = "go_to_element_1_screen"

Screen:
    MDToolbar:
        id: toolbar
        pos_hint: {"top": 1}
        elevation: 10
        left_action_items: [["menu", lambda x: nav_drawer.set_state("open")]]
    MDNavigationLayout:
        x: toolbar.height
        ScreenManager:
            id: screen_manager
            Screen:
                name: "words_nav_item"
            element_1_screen:
                name: "go_to_element_1_screen"
            element_2_screen:
                name: "go_to_element_2_screen"

        MDNavigationDrawer:
            id: nav_drawer
            ContentNavigationDrawer:
                screen_manager: screen_manager
                nav_drawer: nav_drawer
'''

class ContentNavigationDrawer(BoxLayout):
    screen_manager = ObjectProperty()
    nav_drawer = ObjectProperty()

class mainApp(MDApp):
    def build(self):
        self.theme_cls.primary_palette = "Red"
        return Builder.load_string(MainNavigation)

mainApp().run()

屏幕1/元素1

from kivy.lang import Builder
from kivymd.uix.screen import MDScreen

element_1_contents = '''
<element_1_screen>:
    MDGridLayout:
        rows: 2
        size: root.width, root.height
        pos_hint: {"center_x": .8, "center_y": .2}
        spacing: 40
        MDCard:
            orientation: 'vertical'
            size_hint: None, None
            size: "360dp", "120dp"
            ripple_behavior: True
            on_release:
                root.manager.current = "go_to_element_2_screen" 
            MDLabel:
                id: LabelTextID
                text: "Change Text to 1"
                halign: 'center'

        MDCard:
            orientation: 'vertical'
            size_hint: None, None
            size: "360dp", "120dp"
            ripple_behavior: True
            on_release:
                root.manager.current = "go_to_element_2_screen" 
            MDLabel:
                id: LabelTextID
                text: "Change Text to 2"
                halign: 'center'

'''

class element_1_screen(MDScreen):
    def __init__(self,**kwargs):
        super().__init__(**kwargs)
        Builder.load_string(element_1_contents)

屏幕2/元素2

from kivy.lang import Builder
from kivymd.uix.screen import MDScreen
import openpyxl

element_2_contents = '''
<element_2_screen>:
    MDCard:
        orientation: 'vertical'
        size_hint: None, None
        size: "360dp", "360dp"
        pos_hint: {"center_x": .5, "center_y": .5}
        ripple_behavior: True
        focus_behavior: True
        on_release: root.manager.current = "go_to_element_1_screen"

        MDLabel:
            id: TextID
            text: "NOTHING HAS CHANGED"
            halign: 'center'

        MDLabel:
            text: "(Click here to return)"
            halign: 'center'

'''

class element_2_screen(MDScreen):
    def __init__(self,**kwargs):
        super().__init__(**kwargs)
        path = "data.xlsx"
        self.wb_obj = openpyxl.load_workbook(path)
        self.sheet_obj = self.wb_obj.active
        Builder.load_string(element_2_contents)

    def change_text(self, row_x=0):
        row_number = self.sheet_obj.cell(row_x, column=1)
        self.ids.TextID.text = str(row_number.value)

excel文件在a列中只有两个条目:

Row 1: You have chosen 1
Row 2: You have chosen 2
ve7v8dk2

ve7v8dk21#

我找到了答案,现在它完美无瑕。reddit(u/username\u randint)上有人帮了我,他们是这么说的:
屏幕管理器有一个 get_screen() 方法。您可以使用它获取第二个屏幕的示例并调用 change_text() 方法。在切换屏幕的同一位置,添加另一行:

on_release:
        root.manager.current = "go_to_element_2_screen"
        root.manager.get_screen("go_to_element_2_screen").change_text(1)

另一张卡也是一样,只需输入2而不是1。

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