Question

我有这个python文件

from kivy.uix.boxlayout import BoxLayout
from kivy.properties import StringProperty

from kivymd.app import MDApp
from kivy.lang import Builder

from kivymd.theming import ThemableBehavior, ThemeManager
from kivymd.uix.list import OneLineIconListItem, MDList



class ContentNavigationDrawer(BoxLayout):
    pass

class ItemDrawer(OneLineIconListItem):
    icon = StringProperty()

class MainApp(MDApp):
    def on_start(self):
        icons_item = {
            'bug': 'Files'
        }

        for icon_name in icons_item.keys():
            self.root.ids.content_drawer.ids.md_list.add_widget(
                ItemDrawer(icon=icon_name, text=icons_item[icon_name])
            )

class DrawerList(ThemableBehavior, MDList):

    def set_color_item(self, instance_item):
        # Set the color of the icon and text for the menu item.
        for item in self.children:
            if item.text_color == self.theme_cls.primary_color:
                item.text_color = self.theme_cls.text_color
                break
        instance_item.text_color = self.theme_cls.primary_color

MainApp().run()

这个.kv文件看到第3行，该错误来自未定义screen_manager

<ItemDrawer>:
    theme_text_color: "Custom"
    on_release: screen_manager.current = 'screen2'

    IconLeftWidget:
        id: icon
        icon: root.icon
        theme_text_color: "Custom"
        text_color: 0,0,0,1

<ContentNavigationDrawer>:
    orientation: "vertical"
    padding: "8dp"
    spacing: "8dp"

    AnchorLayout:
        anchor_x: "left"
        size_hint_y: None
        height: avatar.height

        Image:
            id: avatar
            size_hint: None, None
            size: "250", "250"
            source: "logo.jpg"

    ScrollView:

        DrawerList:
            id: md_list

NavigationLayout:
    ScreenManager:
        id: screen_manager

        Screen:
            name: 'screen1'

            BoxLayout:
                orientation: 'vertical'


                Widget:
                    canvas:
                        Color:
                            rgba: 0,1,0.2117647058823529,0.3
                        Rectangle:
                            size: self.size
                            pos: self.pos
            MDNavigationDrawer:
                id: nav_drawer
                ContentNavigationDrawer:
                    id: content_drawer
        Screen:
            name: 'screen2'

当我单击导航抽屉中的项目时，它表示未定义 screen_manager

我在做什么错？我在互联网上搜索了很多，但找不到有用的东西

请帮助我，如何更改屏幕？

Answer 1

MDNavigation Drawer 应该与 ScreenManager 处于相同的缩进级别。此外，

        MDNavigationLayout:
            screen_manager:screen_manager
            ScreenManager:
                id: screen_manager
                Screen:
                    name: 'screen1'
                    BoxLayout:
                        orientation: 'vertical'
                        MDToolbar:
                            title: "Navigation Drawer"
                            elevation: 10
                            left_action_items: [['menu', lambda x:nav_drawer.set_state("open")]]
    
                        Widget:
    
                Screen:
                    name: 'screen2'
                    
            MDNavigationDrawer:
                id: nav_drawer
                ContentNavigationDrawer:
                    id: content_drawer

添加

screen_manager:screen_manager

在 NavigationLayout 之下，以便它可以作为 ObjectProperty访问。最后将 ItemDrawer 回调从

on_release: screen_manager.current = 'screen2'

到

on_release: app.root.screen_manager.current = 'screen2'

最后你也可以添加

nav_drawer: nav_drawer

在您的根窗口下方和顶部/下方行screen_manager: screen_manager 这可以在新屏幕弹出时关闭导航抽屉。

然后将您的回调更新为：

on_release:
    app.root.screen_manager.current = 'screen2'
    app.root.nav_drawer.set_state('close')

KivyMd屏幕不会改变

1 个答案: