Jupyter Notebook中使用Kivy遇OSError: source code not available问题求助

问题场景 #

在Jupyter Notebook中尝试用Kivy创建带按钮的窗口，代码分为三个单元格：

1. 第一个单元格导入库并配置窗口，运行正常；
2. 第二个单元格定义App类并尝试用InteractiveLauncher运行，触发错误；
3. 第三个单元格加载KV代码并添加组件，导致窗口崩溃。

原第二个单元格代码 #

from kivy.app import App
from kivy.uix.button import Button
from kivy.interactive import InteractiveLauncher
from kivy.lang import Builder

# 强制禁用全屏
from kivy.config import Config
Config.set("graphics", "fullscreen", "0")

janela = None
glayout= None
...
class WindowApp(App):
    pass

window = WindowApp()
wi = InteractiveLauncher(janela)
wi.run()

触发的错误信息 #

[WARNING] [Deprecated  ] Call to deprecated function __init__ in /home/alfred/anaconda3/envs/k39/lib/python3.10/site-packages/kivy/interactive.py line 308.Called from /tmp/ipykernel_5673/4179568724.py line 5 by <module>().
 Exception in thread Thread-5 (startApp):
 Traceback (most recent call last):
File "/home/alfred/anaconda3/envs/k39/lib/python3.10/threading.py", line 1009, in _bootstrap_inner
     self.run()
   File "/home/alfred/anaconda3/envs/k39/lib/python3.10/threading.py", line 946, in run
     self._target(*self._args, **self._kwargs)
   File "/home/alfred/anaconda3/envs/k39/lib/python3.10/site-packages/kivy/interactive.py", line 319, in startApp
     app.run(*args, **kwargs)
   File "/home/alfred/anaconda3/envs/k39/lib/python3.10/site-packages/kivy/app.py", line 954, in run
     self._run_prepare()
   File "/home/alfred/anaconda3/envs/k39/lib/python3.10/site-packages/kivy/app.py", line 923, in _run_prepare
     self.load_kv(filename=self.kv_file)
   File "/home/alfred/anaconda3/envs/k39/lib/python3.10/site-packages/kivy/app.py", line 676, in load_kv
     default_kv_directory = dirname(getfile(self.__class__))
   File "/home/alfred/anaconda3/envs/k39/lib/python3.10/inspect.py", line 785, in getfile
     raise OSError('source code not available')
 OSError: source code not available

第三个单元格代码及问题 #

kvcode= """FloatLayout:
    Button:
        size_hint: .1, .1
        pos_hint: {"x":.3, "top": 1.}
        text: "A"
"""
glayout= Builder.load_string(kvcode)
janela.root_window.add_widget(glayout)

运行后出现崩溃的黑窗口，因为janela变量为None，调用root_window会引发未定义错误。

错误原因 #

1. InteractiveLauncher已废弃：该类属于Kivy旧版本交互式工具，当前版本已标记废弃，且在Jupyter多线程环境中会触发源码路径获取错误；
2. App类实现不完整：WindowApp未重写build方法返回布局，导致Kivy自动尝试加载同名KV文件，但Jupyter中动态定义的类无法被inspect.getfile获取源码路径，触发OSError；
3. 变量未初始化：janela被赋值为None，后续调用janela.root_window会引发属性错误，导致窗口崩溃。

修正方案 #

方案1：使用runTouchApp（Jupyter环境推荐） #

直接加载KV布局并通过runTouchApp运行，无需定义App类，适配交互式环境：

单元格1：导入库并配置

from kivy.lang import Builder
from kivy.config import Config
from kivy.base import runTouchApp

# 强制禁用全屏
Config.set("graphics", "fullscreen", "0")

单元格2：加载布局并运行

kvcode = """
FloatLayout:
    Button:
        size_hint: .1, .1
        pos_hint: {"x": .3, "top": 1.}
        text: "A"
"""

# 加载KV代码并启动窗口
root_layout = Builder.load_string(kvcode)
runTouchApp(root_layout)

方案2：正确实现App类 #

重写build方法返回布局，避免自动加载KV文件的逻辑：

单元格1：导入库并配置

from kivy.app import App
from kivy.lang import Builder
from kivy.config import Config

Config.set("graphics", "fullscreen", "0")

单元格2：定义App并运行

kvcode = """
FloatLayout:
    Button:
        size_hint: .1, .1
        pos_hint: {"x": .3, "top": 1.}
        text: "A"
"""

class WindowApp(App):
    def build(self):
        # 直接返回加载的布局，跳过自动KV加载流程
        return Builder.load_string(kvcode)

# 在Jupyter中运行App
WindowApp().run()

注意事项 #

• Jupyter中运行Kivy窗口后，关闭窗口可能需要重启内核才能再次运行，避免残留图形上下文冲突；
• 彻底弃用已废弃的InteractiveLauncher，改用官方推荐的runTouchApp或标准App运行方式。

内容的提问来源于stack exchange，提问作者Alfredo Morales