Where to decode a JWT?

I am using android, nodeJS and postgreSQL to build a aplication, and I have a problem that I don't know how to solve :/.

Basicly everytime i login i retrieve a JWT token and store it on the SharedPreferences on android, if the user already has a token in the preference i check if it has already expired or not but that are other stories.

The important to understand for me is related to the decoding of this JWT, when i login i need to decode this token to show the user information

Should i decode it on the mainActivity and pass it trought activitys with intents?

or should i decode it every request?

i have a function that decode my jwt token but just if the user does a request, like this:

    var express = require('express');
var User = require('../models').User;
var router = express.Router();
var jwt = require('jsonwebtoken');

// route middleware to verify a token
module.exports = function () {
    return function (req, res, next) {
        // check header or url parameters or post parameters for token
        var token = req.body.token || req.query.token || req.headers['x-access-token'];
        // decode token
        if (token) {
            // verifies secret and checks exp
            jwt.verify(token, app.get('superSecret'), function (err, decoded) {
                if (err) {
                    return res.json({ success: false, message: 'Failed to authenticate token.' });
                } else {
                    // if everything is good, save to request for use in other routes
                    req.decoded = decoded;
                    next();
                }
            });
        } else {
            // if there is no token
            // return an error
            return res.status(403).send({
                success: false,
                message: 'No token provided.'
            });

        }
    }
};

what is the best way to solve my problem? i can't figure out :S

via Cris dois