我想保存一个变量(标签.text)在kivy中,对于android应用程序,当应用程序重新启动时,它应该将变量加载回标签.text. 在
我试图使用JsonStore保存变量https://kivy.org/docs/api-kivy.storage.html#
有没有更好的方法来保存变量?在
但是当我运行代码时,我得到了以下错误:
ValueError: No JSON object could be decoded
这是我的主.py文件:
from kivy.app import App
from kivy.storage.jsonstore import JsonStore
from kivy.uix.boxlayout import BoxLayout
from kivy.core.window import Window
class Test(BoxLayout):
Window.clearcolor = (1, 1, 1, 1)
def save(self):
store = JsonStore('hello.json')
store.put('tito', score=label.text)
class MyApp(App):
def build(self):
return Test()
def on_start(self):
store = JsonStore('hello.json')
label.text = store.get('tito')['score']
if __name__ == '__main__':
MyApp().run()
这是我的千伏文件:
^{pr2}$以下是完整的错误消息:
Traceback (most recent call last):
File "main.py", line 25, in <module>
MyApp().run()
File "/usr/lib/python2.7/dist-packages/kivy/app.py", line 823, in run
self.dispatch('on_start')
File "kivy/_event.pyx", line 699, in kivy._event.EventDispatcher.dispatch (kivy/_event.c:7394)
File "main.py", line 20, in on_start
store = JsonStore('hello.json')
File "/usr/lib/python2.7/dist-packages/kivy/storage/jsonstore.py", line 25, in __init__
super(JsonStore, self).__init__(**kwargs)
File "/usr/lib/python2.7/dist-packages/kivy/storage/__init__.py", line 133, in __init__
self.store_load()
File "/usr/lib/python2.7/dist-packages/kivy/storage/jsonstore.py", line 34, in store_load
self._data = loads(data)
File "/usr/lib/python2.7/json/__init__.py", line 339, in loads
return _default_decoder.decode(s)
File "/usr/lib/python2.7/json/decoder.py", line 364, in decode
obj, end = self.raw_decode(s, idx=_w(s, 0).end())
File "/usr/lib/python2.7/json/decoder.py", line 382, in raw_decode
raise ValueError("No JSON object could be decoded")
ValueError: No JSON object could be decoded
提前谢谢
这个错误有点普通,但似乎您的JSON无效。您的JSON应该类似于:
您可以在您的
Test
类中使用__init__
方法在开始时加载Json,这比在本例中使用on_start
方法要简单得多。在另一方面,在尝试获取JSON文件和密钥之前,需要测试它是否存在。否则,您可能会收到一个
^{pr2}$KeyError
异常。除此之外,你可以使用try。在相关问题 更多 >
编程相关推荐