如何在Kivy中设置屏幕背景图片

Question

我知道如何制作彩色背景，但我似乎找不到任何有用的内容将图像设置为背景，并且非常感谢您对我的代码的任何帮助。

这是我的.py 文件：

from kivy.app import App
from kivy.uix.screenmanager import ScreenManager, Screen, FadeTransition
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.gridlayout import GridLayout
#from kivy.uix.label import Label
from kivy.uix.button import Button
from kivy.core.window import Window
from kivy.core.image import Image
#from kivy.graphics import BorderImage
from kivy.graphics import Color, Rectangle
#from kivy.uix.image import AsyncImage


class StartScreen(Screen):
    pass

class GameScreen(Screen):
    pass

class RootScreen(ScreenManager):
    pass


class MainApp(App):
    def build(self):
        return RootScreen()

if __name__ == "__main__":
    MainApp().run()

和.kv 文件：

#:import FadeTransition kivy.uix.screenmanager.FadeTransition

<RootScreen>:
    transition: FadeTransition() 
    StartScreen:
    GameScreen:

<StartScreen>:
    name: "start"
    canvas.before:
        Rectangle:
            pos: self.pos
            size: self.size
        Image:
            source: "lights.png"
    FloatLayout:
        Image:     # This part doesn't seem to work
            source: "lights.png"
            allow_stretch: True
            keep_ratio: False
            size_hint: 1, 1
        Button:
            text: "Play!"
            size_hint: 0.4, 0.3
            pos_hint: {'center_x':.5, 'center_y':.5}
            font_size: 70
            on_release: root.manager.current = "game"
<GameScreen>:
    name: "game"
    FloatLayout:
        Button:
            text: "Nazaj!"
            font_size: 70
            on_release: root.manager.current  = "start"

Answer 1

canvas.before:
        Rectangle:
            pos: self.pos
            size: self.size
        Image:
            source: "lights.png"

图像是一个小部件，您不能将其放置在画布上。

您*可以做的就是为矩形设置源：

canvas.before:
        Rectangle:
            pos: self.pos
            size: self.size
            source: 'lights.png'

...或者将您的图像放在其他小部件后面，将它们放入容器布局中。

Answer 2

现在有一个简单的方法可以做到这一点，这里只需添加 FitImage

MDScreen:
    md_bg_color: 239/255, 239/255, 239/255, 1
    name:"entrance"
    FitImage:
        source:"images/yourimagepath.jpg"
    MDBoxLayout:

Answer 3

我的情况，我使用FitImage：

class MainView(MDScreen):
def __init__(self, **kwargs):
    super().__init__(**kwargs)
    
    self.backgroundImage = FitImage(source="src/background.png")
    self.add_widget(self.backgroundImage)