Kivy 和 android 共享首选项

I found Kivy documentation, overall informative, vague in this particular area. It mentions three methods (sorry, dont have enough reputation to provide clicable links, relative paths to kivy.org provided, I'd be glad if someone could fix those links):

1. [存储] ./docs/api-kivy.storage.html#module-kivy.storage
2. [设置] ./docs/api-kivy.uix.settings.html
3. [配置] ./docs/api-kivy.config.html

除此之外，我知道我可以通过 pickle 或数据库将数据存储在文件中，但我想专门使用 sharedpreferences，或至少任何 Android/Kivy 特定的持久存储.

In addition to those, I'm aware that I could store data in a file, via pickle or database, but I'd like to use specifically sharedpreferences, or at least any Android/Kivy specific persistent storage.

1. 但是，我找不到任何比较或解释它们有何不同以及如何使用它们.任何人都可以阐明一下，已经使用过它们了吗?

1. However, I was unable to find any comparison, or explanation how they are different, and how they are used. Could anyone shed some light, had used them already?

实际上，我有 80% 的把握这种方法都没有使用 Android 的共享首选项，因此我考虑使用 jnius (4)，并且我尝试过这样做(方法 1,2/3?,4)，基于简单的 hello world 示例:

Actually, I'm 80% sure that neither of this method uses Android's shared preferences, thus I thought about using jnius (4), and to do that I've tried (methods 1,2/3?,4), based on simple hello world example:

from kivy.app import App
from kivy.uix.button import Button

import jnius  
from kivy.config import Config  
from kivy.storage.dictstore import DictStore  

class MyApp(App):

    def build(self):

        path = "DEFAULT"
        try:  
            path = Config.get('kivy', 'my_important_variable')  
            print "			 KIVY 1:", Config.get('kivy', 'my_important_variable')  
        except Exception as err:
            print ("KIVY, 1, error: {}".format(repr(err)))  

        try:
            store = DictStore("MY_SETTINGS")
            path = store.get("my_important_variable")
            print "			 KIVY 2:", path
        except KeyError as err:
            print ("KIVY, 2, error: {}".format(repr(err)))

        try:
            prefs_m = jnius.autoclass('android.preference.PreferenceManager')
            prefs = prefs_m.getSharedPreferences()
            path = prefs.getString("my_important_variable", None)
            print "			 KIVY 3:", path
        except jnius.jnius.JavaException as err:
            print ("KIVY, 3, error: {}".format(repr(err)))

        btn1 = Button(text=path)
        btn1.bind(on_press=app.callback) #
        return btn1

    def callback(self, instance):
        print('The button <%s> is being pressed, SAVING...' % instance.text)

        try:
            Config.set('kivy', 'my_important_variable', "my_value_1")
        except Exception as err:
            print ("KIVY, 4, error: {}".format(repr(err)))

        try:
            store = DictStore("MY_SETTINGS")
            store.put("MY_SETTINGS", my_important_variable="my_value_2")
        except Exception as err:
            print ("KIVY, 5, error: {}".format(repr(err)))

        try:
            prefs_c = jnius.autoclass('android.content.SharedPreferences')
            prefs_m = jnius.autoclass('android.preference.PreferenceManager')
            prefs = prefs_m.getSharedPreferences()
            prefs_e = prefs.Editor()
            prefs_e.putString("my_important_variable", "my_value_3")
            prefs_e.commit()
        except Exception as err:
            print ("KIVY, 6, error: {}".format(repr(err)))

        try:
            context = jnius.autoclass('android.content.Context')
            # do I actually get context or a class here?
            prefs = context.getPreferences(0).edit();
            prefs.putString("my_important_variable", "my_value_4")
            prefs.commit()
        except Exception as err:
            print ("KIVY, 7, error: {}".format(repr(err)))

if __name__ == '__main__':
    app = MyApp()
    app.run()

这是 logcat 的结果

and here are logcat's results

... each time app is launched 
I/python  ( 5973): KIVY, 1, error: No option 'my_important_variable' in section: 'kivy'
I/python  ( 5973): KIVY, 2, error: KeyError('my_important_variable',)
I/python  ( 5973): KIVY, 3, error: JavaException('Unable to find a None method!',)

... button pressed
I/python  ( 5973): The button <DEFAULT> is being pressed, SAVING...
I/python  ( 5973): KIVY, 6, error: JavaException('Unable to find a None method!',)
I/python  ( 5973): KIVY, 7, error: AttributeError("type object 'android.content.Context' has no attribute 'getPreferences'",)

请注意，没有调用 4、5 个错误消息"，所以理论上它们应该可以工作，但是第二次启动我得到了同样的错误.我已经没有办法破解它了.

Notice, that 4, 5 "error msg's" didn't get called, so in theory they should have worked, but second launch I get same errors. I've run out of ideas how to crack it.

推荐答案

Kivy.Config 用于存储与 App 类的实例化相关的设置.它通常在导入任何其他 kivy 模块之前放置在 Python 脚本的最顶部.此方法不是特定于平台的，但配置文件的默认路径会根据平台而变化.

Kivy.Config is used to store settings that relate to the instantiation of the App class. It is usually placed at the very top of your Python script before any other kivy module is imported. This method is not platform specific, but the default path to the config file changes depending on the platform.

from kivy.config import Config
desktop=Config.getint('kivy', 'desktop')
if desktop == 1:
    print "This app is being run on a desktop."

DictStore 是一个将字典存储到磁盘的存储类.filename 参数指定存储字典的文件的名称.调用 get 函数时，会返回一个 Python 字典.

The DictStore is a storage class that stores a dictionary to disk. The filename argument specifies the name of the file where the dictionary is stored. When the get function is called, a Python dictionary is returned.

from kivy.app import App
from kivy.uix.button import Button
from kivy.storage.dictstore import DictStore

class TestApp(App):
    def build(self):
        try:
            store = DictStore(filename="MY_SETTINGS")
            dictionary = store.get("my_important_variable")
            print "			 KIVY 2: DictStore Succeeded",
        except KeyError as err:
            dictionary = {'name': 'None'}
            print ("KIVY, 2, error: {}".format(repr(err)))

        self.text = str(dictionary)
        btn1 = Button(text=self.text)
        btn1.bind(on_press=self.callback) #
        return btn1

    def callback(self, instance):
        print('The button <%s> is being pressed, SAVING...' % instance.text)
        try:
            store = DictStore(filename="MY_SETTINGS")
            store.put("my_important_variable", name="John")
        except Exception as err:
            print ("KIVY, 5, error: {}".format(repr(err)))



if __name__ == '__main__':
    TestApp().run()

我将在下面提供访问共享首选项的代码.如果您有兴趣了解更多信息，请阅读 http://developer.android.com/guide/topics/data/data-storage.html 和 https://kivy.org/planet/2015/04/python-on%C2%A0android/

I will provide the code for accessing shared prefs below. If you are interested in learning more please read http://developer.android.com/guide/topics/data/data-storage.html and https://kivy.org/planet/2015/04/python-on%C2%A0android/

from kivy.app import App
from kivy.uix.button import Button

import jnius

class TestApp(App):
    def build(self):
        try:
            PythonActivity = jnius.autoclass('org.renpy.android.PythonActivity')
            activity = PythonActivity.mActivity
            cntxt = activity.getApplicationContext()
            prefs = cntxt.getSharedPreferences("MY_PREFS", cntxt.MODE_PRIVATE )
            print "KIVY ACQUIRED SHARED PREFS"
            myVar = prefs.getString("my_important_variable", "Default String")
            print "	KIVY 3: Retrieved SharedPref"
        except jnius.jnius.JavaException as err:
            myVar="Error Loading Prefs."
            print ("KIVY, 3, error: {}".format(repr(err)))

        self.text = myVar
        btn1 = Button(text=self.text)
        btn1.bind(on_press=self.callback) #
        return btn1

    def callback(self, instance):
        print('The button <%s> is being pressed, SAVING...' % instance.text)
        try:
            PythonActivity = jnius.autoclass('org.renpy.android.PythonActivity')
            activity = PythonActivity.mActivity
            cntxt = activity.getApplicationContext()
            prefs = cntxt.getSharedPreferences("MY_PREFS", cntxt.MODE_PRIVATE)
            editor = prefs.edit()
            editor.putString("my_important_variable", "This is important!")
            editor.commit()
            print "	KIVY: Added string <This is important!> to shared prefs."
        except Exception as err:
            print ("	KIVY, 6, error: {}".format(repr(err)))

if __name__ == '__main__':
    TestApp().run()

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