How to correctly use the kivy.storage.JsonStore module?

[Benjamin Ward]

  I have been playing with the JsonStore example, and cannot figure out how to access what the keys  are storing. For instance, I could do:

for key in store.get('tito'):
    print(key)

but that only gives me the name of the key.

Now, I'm sure I could find some convoluted way to do this, but I would rather know how this is properly done.


Benjamin Ward

[ZenCODE]

Hi

Yes, the docs er... give me an error. Will make a note to correct that shortly.

But this works.

from kivy.storage.jsonstore import JsonStore

store = JsonStore('hello.json')

# put some values
store.put('tito', name='Mathieu', age=30)
store.put('tshirtman', name='Gabriel', age=27)

# get from a key
print('tito is', store.get('tito'))

# or guess the key/entry for a part of the key
#key, tshirtman = store.find(name='Gabriel')
#print('tshirtman is', tshirtman)
res = store.find(name='Gabriel')
for item in res:
    print "res=", str(item)
    print "res=", str(item[1]['age'])

It looks like "find" returns a generator (iterator) for the list of results. Each item in this list is a tuple of key and dictionary values. So for the search above. one item is found. this item is a tuple:

    res= (u'tshirtman', {'age': 27, 'name': 'Gabriel'})

Cheers

[Benjamin Ward]

Thank you! (This is one of the reasons that I love Kivy so much, there are not that many that are using it, but the people who are are the best :D )

[Benjamin Ward]

Actually, another question:

I know how to retrieve the values from the tuple? I have never used a dict inside of a tuple before, so is there a special way to do it?

On Friday, February 28, 2014 4:13:50 PM UTC-5, Benjamin Ward wrote:

[Benjamin Ward]

Nevermind.... I am being dumb today :P

I saw how you did it in the code that you posted.... Thanks Zen!

[ZenCODE]

:-) And thanks for the nice words. Makes it all worthwhile....;-)

[Andrei Sima]

Hi, 

I have some problems in properly using / implementing JsonStore.

.py file

from kivy.app import App

from kivy.storage.jsonstorage import JsonStore

from kivy.uix.label import Label
from kivy.uix.boxlayout import BoxLayout

store = JsonStore('hello.json')

store.put('tito', name='Mathieu', age=30)
store.put('tshirtman', name='Gabriel', age=27)

class MyLayout (BoxLayout):
    pass

class MyApp (App):
    def build (self):
        return MyLayout()

if __name__ == 'main':
   MyApp().run()

.kv file

<MyLayout>
    Label:
        text: store.get('tito')['name'] # store not defined which is correct

    Label:
        text: root.store.get('tito')['name'] # MyLayout does not have a property store correct also

I have tried to define store inside MyLayout python class but with no success.

1. Where should be store defined so i can use it inside .kv file?

2. If i change a value inside store will that change be reflected in widget? Or the widget will only one time read the value and is not bind to it?

Thank you.

[Andrei Sima]

After tinkering some more with store..... I had managed to implement it 

.kv

<MyLayout>

    Label:
        text: app.store.get('channel4')['name']     # this needs to be bind to jsonData

...

.py

....

class MyLayout(BoxLayout):
    app = App.get_running_app()
    print (app.store.get('channel4'))     # is printing the initial value from json
    app.store.put ('channel4', name = 'some other name')
    print (app.store.get('channel4')      # is printing the new value but the label from kv will not update

....

class MyApp (self) :
    def build (self):
        self.store = JsonStore (myJsonData)
        self.store.put(<somevalues>)

As for question 2 if i change the value in store that change will not be reflected in widget. I guess is one time read and not binding.

I will try to bind them.... but if the json data is big... we will see

I was hopping that the store will work something similar to store in js webframeworks ( ex: Vue.js and his store Vuex). But i guess that is not the case. 

____________________

Andrei Sima

andre...@gmail.com

0723.223.883

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[Elliot Garbus]

You want to use a kivy StringProperty.  Declare the string property in MyLayout.  Update the String property when setting new data.

 

from kivy.properties import StringProperty

class MyLayout(BoxLayout):
    my_jsondata = StringProperty('Initial Data') # this looks like a class variable, but it is an instance variable.

    def update_data(self, new_data):
        app = App.get_running_app()
        print (app.store.get('channel4'))     # is printing the initial value from json
        self.my_jsondata = new_data
        app.store.put ('channel4', name = new_data)
        print (app.store.get('channel4'))  
        

in KV point use the string property to update the text:

 

.kv

<MyLayout>

    Label:
        text: root.my_jsondata     # this will update when my_jsondata changes.

To view this discussion on the web visit https://groups.google.com/d/msgid/kivy-users/CAGfUSDKYMEf70kgXMqM8d7A%2BeEm88DWg_kepUgMPWbTYisrMgw%40mail.gmail.com.

[Prabhat Mohanty]

We could perhaps declare the global variables in python, load the value from JSON and then use anywhere!

--

[Andrei Sima]

@ Eliot

This is how I have managed to make it work in the end. I will post a working code for future reference.

@Prabhat

Kivy object properties will behave better than python ones. 

Thank you

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[Andrei Sima]

The problem with kivy.storage.jsonstore is that the store is available to late for me or i did not fully understand module uage.

So i made a custom store for my json data.

Working code for future reference

main.py (relevant code)

import store

_data = store.data

....

class MyLayout (BoxLayout):
     labelValue = StringProperty()

    def __init__(self, **kwargs):
         super (MyLayout, self).__init__(**kwargs)
         self.labelValue = str(_data['channel4']['name'] )
         self.bind (labelValue = self.on_update)

     def set_label_value(self):
         self.labelValue = store.update_data('channel4', 'name', 'some other name') # will receive data hard coded for test
    

     def on_update(self, instance, value, *args):
          print('Item changed in: {},\nModified to: {}.'.format(instance, value))

*.kv

Button:

text: 'clickme'
on_release: root.set_label_value() # the data will be passed here

store.py

import json
import pandas as pd

# Read Initial JSON

with open('switches_list.json') as f:
df_switches = pd.read_json(

f,
orient = 'index'

)

data = df_switches.to_dict(orient='index')

def update_data(key, value, payload):       # change js scum payload with args or kwargs

df_switches.at[key, value] = payload
return df_switches.loc[key].at[value]

I will try to polish the code some more just to make it more python minded. This is just a quick dirty way to make it work.

____________________

Andrei Sima

andre...@gmail.com

0723.223.883

[srinivas sagit]

Jsonstore is not allowing to give user defined name for a key!

வெள்., 12 ஜூலை, 2019, பிற்பகல் 12:54 அன்று Andrei Sima <andre...@gmail.com எழுதியது:

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[Andrei Sima]

Jsonstore is not allowing to give user defined name for a key!

RLY?

Before giving an answer or solution please at least read the documentation

https://kivy.org/doc/stable/api-kivy.storage.html

# put some values
store.put('tito', name='Mathieu', org='kivy')

store.put('tshirtman', name='Gabriel', age=27)

# get a value using a index key and key
print('tito is', store.get('tito')['age'])

# using the same index key erases all previously added key-value pairs

store.put('tito', name='Mathieu', age=30)

____________________

Andrei Sima

andre...@gmail.com

0723.223.883

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[srinivas sagit]

Json Store problem!

self.store = JsonStore('comp.json')

self.store. put('components',switch="crompton")

Instead of giving "switch" I want to give user input!

I tried to change it gives SyntaxError: keyword can't be an expression! 

I read the latest docx!

சனி, 13 ஜூலை, 2019, பிற்பகல் 6:27 அன்று Andrei Sima <andre...@gmail.com எழுதியது:

To view this discussion on the web visit https://groups.google.com/d/msgid/kivy-users/CAGfUSDLEOxLejcgJPm40-eRmq98A-WzSUnjD6-j2XspH8_eS%3Dg%40mail.gmail.com.

[Elliot Garbus]

Key word arguments use dictionaries to pass the keyword value pairs.  I suspect you did not pass a dictionary.

How did you make the call? 

 

Here is a small example of how key word arguments and dictionaries work.

 

from kivy.storage.jsonstore import JsonStore


def show_me(**kwargs):
    print(kwargs)
    for k,v in kwargs.items():
        print(f'{k} = {v}')


d1 = {'dog': 1, 'cat': 2, 'mouse': 3}

print('\nPass a dictionary as keywords')
show_me(**d1)

print('\nPass Keywords')
show_me(box=4, fox=5, eggs=6)

store = JsonStore('test_1.json')
store.put('color', red=1, white=2, blue=3)
store.put('critters', **d1)
print(f"\nstore.get('critters') = {store.get('critters')}")

 

Here is the output of the code:

Pass a dictionary as keywords

{'dog': 1, 'cat': 2, 'mouse': 3}

dog = 1

cat = 2

mouse = 3

 

Pass Keywords

{'box': 4, 'fox': 5, 'eggs': 6}

box = 4

fox = 5

eggs = 6

 

store.get('critters') = {'dog': 1, 'cat': 2, 'mouse': 3}

 

Here is the contents of test_1.json:

{"color": {"red": 1, "white": 2, "blue": 3}, "critters": {"dog": 1, "cat": 2, "mouse": 3}}

 

 

 

From: srinivas sagit
Sent: Sunday, July 14, 2019 5:36 AM
To: kivy-...@googlegroups.com
Subject: Re: [kivy-users] Re: How to correctly use the kivy.storage.JsonStore module?

 

Json Store problem!

To view this discussion on the web visit https://groups.google.com/d/msgid/kivy-users/CAAytCsht5hXCz-fB3HE8nQUEi_V1Vha7e9MvTOyCU98fYZzrBQ%40mail.gmail.com.

[srinivas sagit]

Thank you so much Elliot!

ஞாயி., 14 ஜூலை, 2019, பிற்பகல் 8:35 அன்று Elliot Garbus <elli...@cox.net எழுதியது:

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