问题
I am trying to make a simple app made from Kivy on Windows:
import kivy
from kivy.app import App
from kivy.uix.label import Label
class MyApp(App):
def build(self):
return Label(text='Hello world')
if __name__ == '__main__':
MyApp().run()
(EDIT) But each time I get this very long error; this is all of it:
[INFO ] [Logger ] Record log in C:\Users\danie\.kivy\logs\kivy_16-07-15_5.txt
[INFO ] [Kivy ] v1.9.1
[INFO ] [Python ] v3.4.4 (v3.4.4:737efcadf5a6, Dec 20 2015, 20:20:57) [MSC v.1600 64 bit (AMD64)]
[INFO ] [Factory ] 179 symbols loaded
[INFO ] [Image ] Providers: img_tex, img_dds, img_gif, img_sdl2, img_pil (img_ffpyplayer ignored)
[INFO ] [Text ] Provider: sdl2
[INFO ] [OSC ] using <thread> for socket
[INFO ] [Window ] Provider: sdl2
[INFO ] [GL ] GLEW initialization succeeded
[INFO ] [GL ] OpenGL version <b'4.4.0 - Build 10.18.15.4271'>
[INFO ] [GL ] OpenGL vendor <b'Intel'>
[INFO ] [GL ] OpenGL renderer <b'Intel(R) HD Graphics 530'>
[INFO ] [GL ] OpenGL parsed version: 4, 4
[INFO ] [GL ] Shading version <b'4.40 - Build 10.18.15.4271'>
[INFO ] [GL ] Texture max size <16384>
[INFO ] [GL ] Texture max units <32>
[INFO ] [Shader ] fragment shader: <b"WARNING: 0:6: '' : #version directive missing">
[INFO ] [Shader ] vertex shader: <b"WARNING: 0:6: '' : #version directive missing">
[WARNING ] [Image ] Unable to load image <C:\Python34\lib\site-packages\kivy\data\glsl\default.png>
[CRITICAL ] [Window ] Unable to find any valuable Window provider at all!
sdl2 - Exception: SDL2: Unable to load image
File "C:\Python34\lib\site-packages\kivy\core\__init__.py", line 67, in core_select_lib
cls = cls()
File "C:\Python34\lib\site-packages\kivy\core\window\window_sdl2.py", line 138, in __init__
super(WindowSDL, self).__init__()
File "C:\Python34\lib\site-packages\kivy\core\window\__init__.py", line 722, in __init__
self.create_window()
File "C:\Python34\lib\site-packages\kivy\core\window\window_sdl2.py", line 255, in create_window
super(WindowSDL, self).create_window()
File "C:\Python34\lib\site-packages\kivy\core\window\__init__.py", line 897, in create_window
self.render_context = RenderContext()
File "kivy\graphics\instructions.pyx", line 756, in kivy.graphics.instructions.RenderContext.__init__ (kivy\graphics\instructions.c:10729)
File "C:\Python34\lib\site-packages\kivy\core\image\__init__.py", line 512, in __init__
self.filename = arg
File "C:\Python34\lib\site-packages\kivy\core\image\__init__.py", line 700, in _set_filename
mipmap=self._mipmap, nocache=self._nocache)
File "C:\Python34\lib\site-packages\kivy\core\image\__init__.py", line 430, in load
im = loader(filename, **kwargs)
File "C:\Python34\lib\site-packages\kivy\core\image\__init__.py", line 198, in __init__
self._data = self.load(filename)
File "C:\Python34\lib\site-packages\kivy\core\image\img_sdl2.py", line 42, in load
raise Exception('SDL2: Unable to load image')
[CRITICAL ] [App ] Unable to get a Window, abort.
Exception ignored in: 'kivy.properties.dpi2px'
Traceback (most recent call last):
File "C:\Python34\lib\site-packages\kivy\utils.py", line 513, in __get__
retval = self.func(inst)
File "C:\Python34\lib\site-packages\kivy\metrics.py", line 175, in dpi
EventLoop.ensure_window()
File "C:\Python34\lib\site-packages\kivy\base.py", line 126, in ensure_window
sys.exit(1)
SystemExit: 1
[CRITICAL ] [App ] Unable to get a Window, abort.
I can't understand why this error is appearing, can you help me out of this?
回答1:
Though the installation instructions say gstreamer is optional I had to install it to get kivy to work (windows). As on the installation page:python -m pip install kivy.deps.gstreamer --extra-index-url https://kivy.org/downloads/packages/simple/
(uninstalling reproduced the error above, installing it again fixed it again)
回答2:
The gstreamer suggestion was misleading in my case, since it seems it was fixed before 1.9.1 version I'm using. The error is documented in a little obscure pass of the documentation here:
If kivy was not installed using the wheels method these commands will not work and e.g. kivy.deps.sdl2 will fail to import. Instead, one must find the location of these dlls and manually pass them to the Tree class in a similar fashion as the example.
Basically it's a binary / dll issue on Windows caused by the fact I'm not using the "wheels method" (aka I've used a virtualenv and done my pip install there). I've fixed this way:
- Locate the python share folder on windows. E.g. in a virtualenv you will find it on X:\virtualentpath\share
- Copy the glew and sdl2 directory
- After you've done step 2 here and before step 3, in the dist folder create a share folder and paste glew and sdl directories in it
Add the libraries path to the myappname.spec file
coll = COLLECT(exe, Tree('dist\\share\\glew\\bin\\'), Tree('dist\\share\\sdl2\\bin\\'), Tree('c:\\Users\\myuser\\PycharmProjects\\myappname\\'), a.binaries, a.zipfiles, a.datas, strip=False, upx=True, name='myappname')
If you need gstreamer you have to add it, if you don't need you haven't. It's important because the only gstreamer library is something like 44 times larger than the basic two:
- glew + sdl = 7.31MB
- gstreamer = 323MB
I don't know if it's the right method but after I stumbled on a red herring after another in several hours this is the only method that works in my case.
Rewriting that last paragraph in the Kivy documentation will help in this cases on Windows.
来源：https://stackoverflow.com/questions/38390789/i-always-get-this-error-when-creating-a-kivy-app