Kivy: Error on iOS using JSON file for High Score

Question

I tried to set up a highscore tracker for an app by using a JSON file and the json storage language in Kivy.

I imported JSONstore and in my main game class I did

class Game(FloatLayout):
    highscorejson = JsonStore('highscore.json')
    highscore = NumericProperty(highscorejson.get('highscore')['best'])

and after I init the class, I have an end game function that ends the game and checks to see if the new score beats the old highscore.

def end_game(self):
    if self.score > self.highscore:
         self.highscorejson.put('highscore', best = self.score)
    self.highscore = self.highscorejson.get('highscore')['best']

This runs perfectly when I run it through Kivy, but when I run it through XCode using my iphone as a test device, it crashes when you score above the highscore and the game ends. The error message is as below.

  File "/usr/local/lib/python2.7/site-packages/kivy/storage/__init__.py", line 174, in put
   File "/usr/local/lib/python2.7/site-packages/kivy/storage/jsonstore.py", line 39, in     store_sync
 IOError: [Errno 1] Operation not permitted: 'highscore.json'
2014-06-24 21:59:34.385 cookie[2320:60b] Application quit abnormally!
2014-06-24 21:59:34.457 cookie[2320:60b] Leaving

Full Error: http://pastebin.com/Zy0DtysW

Answer 1

You're probably trying to save the file in an invalid location. Try including a full path to the file you want to write out - you can use kivy_home_dir to help with this.

from kivy import kivy_home_dir
from os.path import join
highscore = JsonStore(join(kivy_home_dir, 'highscore.json'))

Answer 2

I was stuck on this problem too. So, finally, I was able to solve this problem. The next code helped me a lot.

from os.path import join

class MyApp(App):
def build(self):
    data_dir = getattr(self, 'user_data_dir')
    store = JsonStore(join(data_dir, 'storage_file.json'))

As I understand, user_data_dir stores an unique for each app and OS path, where current app's code is stored.