Android - Best way to use colors from JSON file

Question

I'm working on an app that will retrieve a colors.json file from server. This file will have the following structure:

[
    {"ServerActionButton.background.normal":
        { "red": 29, "green": 188, "blue": 189, "alpha":255}
    },
    {"ServerActionButton.background.disabled": 
        { "red": 164, "green": 228, "blue": 229, "alpha":255}
    },
    {"ServerActionButton.title.normal": 
        { "red": 255, "green": 255, "blue": 255, "alpha":255}
    },
    ...
]

This JSON should be retrieved on app startup, and I should be able to use these colors throughout the whole app.

Question: What's the best way to do this? I've thought about the following options:

Generating a resource XML file from the JSON (it would be great, but is it possible?).
Mapping the JSON to a model, and then storing it in SharedPreferences.
Building a local database with the data retrieved from the JSON.

Which would be the best approach? Is there some other possibility I'm not considering?

Thanks in advance!

The app is intended to be used always online. However, I think the best way would be to call the colors service just once (at startup). — Nadia Castelli, Apr 15 '16 at 03:15

score 0 · Answer 1 · answered Apr 15 '16 at 03:39

Consider a more hierarchical structure:

[
    {
        "item" : "ServerActionButton",
        "styles" : {
            "normal" :
                          {
                             "title" :      "#FFFFFFFF",
                             "background" : "#FF1DBCBD"
                          },

             "disabled" : {
                             "title" :      "#FF7F7F7F",
                             "background" : "#FF1DBCBD"
                          }
         }
    },

    ...
]

Then that's easily parsed into a map (or a map of maps)

class StyleProperties
{
    public Color title;
    public Color background;
}



HashMap<String, HashMap<String, StyleProperties>> stylemappings = YourFunctionToParseTheJson(strJson);

And then you can easily apply styles to elements as follows:

void ApplyStylesToView(View v, String item, String style)
{
    StyleProperty styleProp = null;

     HashMap<String, StyleProperties> stylePropertiesForItem = stylemappings.get("item");

     if (stylePropertiesForItem != null)
     {
          styleProp = stylePropertiesForItem.get(style);

          v.setBackgroundColor(styleProp.background);

          // if the item is a textview, apply the title color
          TextView tv = v as TextView;
          if (v instanceof TextView)
          {
              ((TextView)v).setTextColor(styleProp.title);
          }
     }
}

Android - Best way to use colors from JSON file

1 Answers1