当我在kivy中运行程序“ Hello World”时，没有显示文字，为什么？

Question

所有信息告诉我：

我不知道该添加到路径

运行：

请告诉我一切，完美。

'''python

import kivy
from kivy.app import App
from kivy.uix.label import Label

class A(App):
    def build(self):
        return Label(text='Hello world!')

A().run()

''' 运行程序和结果 '''控制台

[INFO   ] [Logger      ] Record log in C:\Users\1\.kivy\logs\kivy_19-07-02_6.txt
[INFO   ] [deps        ] Successfully imported "kivy_deps.gstreamer" 0.1.17
[INFO   ] [deps        ] Successfully imported "kivy_deps.glew" 0.1.12
[INFO   ] [deps        ] Successfully imported "kivy_deps.sdl2" 0.1.22
[INFO   ] [Kivy        ] v1.11.1
[INFO   ] [Kivy        ] Installed at "C:\Users\1\AppData\Roaming\Python\Python36\site-packages\kivy\__init__.py"
[INFO   ] [Python      ] v3.6.1 (v3.6.1:69c0db5, Mar 21 2017, 18:41:36) [MSC v.1900 64 bit (AMD64)]
[INFO   ] [Python      ] Interpreter at "C:\Program Files\Python36\pythonw.exe"
[INFO   ] [Factory     ] 184 symbols loaded
[INFO   ] [Image       ] Providers: img_tex, img_dds, img_sdl2, img_pil, img_gif (img_ffpyplayer ignored)
[INFO   ] [Text        ] Provider: sdl2
[INFO   ] [Window      ] Provider: sdl2
[INFO   ] [Window      ] Activate GLES2/ANGLE context
[INFO   ] [GL          ] Using the "OpenGL" graphics system
[INFO   ] [GL          ] Backend used <angle_sdl2>
[INFO   ] [GL          ] OpenGL version <b"OpenGL ES 2.0 (ANGLE 2.1.0.b'')">
[INFO   ] [GL          ] OpenGL vendor <b'Google Inc.'>
[INFO   ] [GL          ] OpenGL renderer <b'ANGLE (AMD Radeon Series Direct3D11 vs_5_0 ps_5_0)'>
[INFO   ] [GL          ] OpenGL parsed version: 2, 0
[INFO   ] [GL          ] Shading version <b"OpenGL ES GLSL ES 1.00 (ANGLE 2.1.0.b'')">
[INFO   ] [GL          ] Texture max size <16384>
[INFO   ] [GL          ] Texture max units <16>
[INFO   ] [Window      ] auto add sdl2 input provider
[INFO   ] [Window      ] virtual keyboard not allowed, single mode, not docked
[INFO   ] [Base        ] Start application main loop
[INFO   ] [GL          ] NPOT texture support is available

'''

Answer 1

我试图按原样运行代码，并且运行正常。