Kivy:错误弱引用对象(在时钟函数中)不再存在

问题描述

这是我的错误代码我认为这个错误有什么难的地方，我在论坛上找过，但没有找到.

So here is my error code I think there's something hard in this error, i looked on forums but couldn't find out.

而且...我的手机出现错误(使用 kivy启动器 python 3 以及当我使用 buildozer 构建时)但不在我的计算机上(ubuntu 18.0.4 和 windows 10)据我了解，该错误来自删除引用的垃圾收集器，并且代码尝试在垃圾收集器之后访问引用.但我不确定我是否理解垃圾收集器的事情

And ... i have the error on my phone (with kivy launcher python 3 and when i build with buildozer) but not on my computer (ubuntu 18.0.4 and windows 10) The error, from what i understand, comes from the garbage collector that delete a reference and the code try to access the reference after the garbage collector. but i am not sure if I rly understand the garbage collector thing

我尝试了什么:

• 制作强引用"，以便 gc 不会将其删除:

    id: id.__self__

在我的 kv 文件中

• 使用以下方法进行强引用":

     self.refs = [
                self.id.__self__,
                self.id.__self__]

-使用ErrorHandler来处理错误，但错误总是会出现

-Use the ErrorHandler to handle the error but the error keep coming for ever

我认为是什么导致了错误，但我不知道如何解决它:

• 我用来向服务器发送请求的时钟，但我不知道为什么(self.requestClient 是一个发送请求的函数):

• the clock I use to send request to the server but i don't know why (self.requestClient is a function to send a request) :

C = Clock.schedule_interval(self.requestClient, 5)

C = Clock.schedule_interval(self.requestClient, 5)

此信息在 kivy 时钟文档 :

重要

回调是弱引用的:你负责保持一个引用您的原始对象/回调.如果你不保留一个参考，ClockBase 永远不会执行你的回调

The callback is weak-referenced: you are responsible for keeping a reference to your original object/callback. If you don’t keep a reference, the ClockBase will never execute your callback

错误:

[ERROR  ] Exception catched by ExceptionHandler
05-07 11:27:45.694  2788  2823 I python  : Traceback (most recent call last):
05-07 11:27:45.694  2788  2823 I python  :   File path/kivy-launcher/.buildozer/android/platform/build-armeabi-v7a/build/python-installs/launcher/kivy/core/window/window_sdl2.py", line 747, in mainloop
05-07 11:27:45.694  2788  2823 I python  :   File "/path/kivy-launcher/.buildozer/android/platform/build-armeabi-v7a/build/python-installs/launcher/kivy/core/window/window_sdl2.py", line 479, in _mainloop
05-07 11:27:45.694  2788  2823 I python  :   File "/path/kivy-launcher/.buildozer/android/platform/build-armeabi-v7a/build/python-installs/launcher/kivy/base.py", line 339, in idle
05-07 11:27:45.694  2788  2823 I python  :   File "/path/kivy-launcher/.buildozer/android/platform/build-armeabi-v7a/build/python-installs/launcher/kivy/clock.py", line 591, in tick
05-07 11:27:45.694  2788  2823 I python  :   File "kivy/_clock.pyx", line 384, in kivy._clock.CyClockBase._process_events
05-07 11:27:45.694  2788  2823 I python  :   File "kivy/_clock.pyx", line 414, in kivy._clock.CyClockBase._process_events
05-07 11:27:45.694  2788  2823 I python  :   File "kivy/_clock.pyx", line 412, in kivy._clock.CyClockBase._process_events
05-07 11:27:45.694  2788  2823 I python  :   File "kivy/_clock.pyx", line 154, in kivy._clock.ClockEvent.tick
05-07 11:27:45.694  2788  2823 I python  :   File "kivy/_clock.pyx", line 86, in kivy._clock.ClockEvent.get_callback
05-07 11:27:45.694  2788  2823 I python  :   File "/path/kivy-launcher/.buildozer/android/platform/build-armeabi-v7a/build/python-installs/launcher/kivy/weakmethod.py", line 56, in is_dead
05-07 11:27:45.694  2788  2823 I python  : ReferenceError: weakly-referenced object no longer exists

感谢阅读！

推荐答案

官方文档(Kv 语言编程指南) 说要在 KV 代码中添加诸如 id_name: id_name.__self__ 之类的强"引用，但不清楚这在哪里是必要的.更重要的是，它并没有为我解决 ReferenceError:weakly-referenced object no longer exists 错误.

The official documentation (Kv language Programming Guide) says to add 'strong' references such as id_name: id_name.__self__ in the KV code, but it is unclear where this is necessary. What's more, it did not solve the ReferenceError: weakly-referenced object no longer exists errors for me.

所做 的工作是通过将其添加到 buildozer.spec 文件的 requirements 行来强制 Buildozer 使用特定版本的 hostpython3:

What did work is forcing Buildozer to use a specific version of hostpython3 by adding this to the requirements line of the buildozer.spec file:

python3==3.7.5, hostpython3==3.7.5

还有一点需要注意:在将上述内容添加到 requirements 之后，我返回并删除了所有 __self__ 引用，它仍然可以正常工作，因此显然不再需要这些引用在 Kivy KV 语言中.

One more note: after adding the above to requirements, I went back and removed all my __self__ references and it still worked fine, so apparently these are no longer needed in Kivy KV language.

这要归功于 leo10011 的精彩回答.

2020-05-19 更新:这个错误 据报道已在 Kivy 2.0 中修复.

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