Question

I wrote an jQuery Mobile app and packaged it with Phonegap to iOS and Android apps.

At this point I am using locally stored json files to read data.

I would like to update these json files from time to time by downloading newer json files from a server.

How can I get the json from the server and store the json files to the local file system of Android and iOS?

Cheers
Johe

Answer 1

This is how I solved it. First set the file paths, wich are different for Android and iOS

var file_path;
function setFilePath() {
    if(detectAndroid()) {   
        file_path = "file:///android_asset/www/res/db/";
        //4 Android
    } else {
        file_path = "res//db//";
        //4 apache//iOS/desktop
    }
}

Then I load my JSON files, wich are prepackaged with the app, into the local browser storage. Like this:

localStorage["my_json_data"] = loadJSON(file_path + "my_json_data.json");

function loadJSON(url) {
    return jQuery.ajax({
        url : url,
        async : false,
        dataType : 'json'
    }).responseText;
}

If I wanna update my data. I get the new JSON Data from the server and push it into the local storage. If the server is on a different domain, which is the case most of the time, you have to make a JSONP call (check jQuery’s docs on JSONP).
I did it kinda like this:

$.getJSON(my_host + 'json.php?function=' + my_json_function + '&callback=?', function (json_data) {
    //write to local storage
    localStorage["my_json_data"] = JSON.stringify(json_data);

});