Parsing Json array-Windows phone

Looking forward on improving the GPS phone tutorial from last time, will be adding our pushpins and markers from a JSON(JavaScript Object Notation) array, so the first step will be to learn how to parse our array, this blog post will be short because this is not our main goal.

I will be using a PHP and WAMP server to locally host my the json data.
Requirements:

1. wamp server download HERE
2. Visual studio
3. Newtonsoft.json.dll download HERE or you can install directly to your project in visual studio follow these steps:

• click the project tab in visual studio
• click manage NuGet packages
• wait for it to load and select Json.NET click install, this will allow us import the Newtonsoft.json.dll library.

Let us begin by setting up our JSON data from our database through PHP. I am not going to explain the PHP code but the comments within the code should be really helpful.

I won't be going into database configuration either, if need help on that visit this website Kiwixcompo

If you can recall GPS phone was about finding restaurants on the map and call for a reservation or place an order. Our json encoded data has to fit this need.

This is the PHP script to encode our data.

This our db_connect.php file with our connection variables

<?php
define('DB_USER', "root");
define('DB_PASSWORD', "");
define('DB_DATABASE', "jsontest");
define('DB_SERVER', "localhost");
?>

This is our db_kinnect.php file which checks out database connection status and connects us to the database

<?php
 
/**
 * A class file to connect to database
 */
class DB_CONNECT {
 
    // constructor
    function __construct() {
        // connecting to database
        $this->connect();
    }
 
    // destructor
    function __destruct() {
        // closing db connection
        $this->close();
    }
 
    /**
     * Function to connect with database
     */
    function connect() {
        // import database connection variables
        require_once __DIR__ . '/db_connect.php';
 
        // Connecting to mysql database
        $con = mysql_connect(DB_SERVER, DB_USER, DB_PASSWORD) or die(mysql_error());
 
        // Selecing database
        $db = mysql_select_db(DB_DATABASE) or die(mysql_error()) or die(mysql_error());
 
        // returning connection cursor
        return $con;
    }
 
    /**
     * Function to close db connection
     */
    function close() {
        // closing db connection
        mysql_close();
    }
 
}
 
?>

This is the file that wil spit out our JSON from the database for our mobile consumption

<?php
 
/*
 * Following code will list all the Restaurants
 */
 
// array for JSON response
$response = array();
 
// include db connect class
require_once __DIR__ . '/db_kinect.php';
 
// connecting to db
$db = new DB_CONNECT();
 restaurants") or die(mysql_error());
 
// check for empty result
if (mysql_num_rows($result) > 0) {
    // looping through all results
    // restaurants node
    $response["restaurants"] = array();
 
    while ($row = mysql_fetch_array($result)) {
        // temp user array
        $restaurants_array = array();
        $restaurants_array["pid"] = $row["pid"];
        $restaurants_array["longitude"] = $row["longitude"];
        $restaurants_array["latitude"] = $row["latitude"];
        $restaurants_array["created_at"] = $row["created_at"];
        $restaurants_array["updated_at"] = $row["updated_at"];
        
        // push single restaurant into final response array
        array_push($response["restaurants"], $restaurants_array);
    }
    // success
    $response["success"] = 1;
 
    // echoing JSON response
    echo json_encode($response);
} else {
    // no location found
    $response["success"] = 0;
    $response["message"] = "No location found";
 
    // echo no users JSON
    echo json_encode($response);
}
?>

The php code above should give us the required json we desire. see out put below

{"restaurants":[{"pid":"1","longitude":"46.8799000000","latitude":"35.8779000000","created_at":"2014-02-09 17:24:49","updated_at":"0000-00-00 00:00:00"},{"pid":"2","longitude":"25.5858660000","latitude":"62.8585850000","created_at":"2014-02-09 19:51:14","updated_at":"0000-00-00 00:00:00"},{"pid":"3","longitude":"9.3241082570","latitude":"9.1728899140","created_at":"2014-02-11 23:52:43","updated_at":"0000-00-00 00:00:00"},{"pid":"4","longitude":"8.8359202210","latitude":"7.4974748750","created_at":"2014-02-11 23:52:43","updated_at":"0000-00-00 00:00:00"}],"success":1}

That is all the PHP-ing we will be doing (thank God); copy the output json and goto Json2csharp.com paste the json output and click generate button you will get two csharp classes that looks like these ones below

public class Restaurant
{
    public string pid { get; set; }
    public string longitude { get; set; }
    public string latitude { get; set; }
    public string created_at { get; set; }
    public string updated_at { get; set; }
}

public class RootObject
{
    public List restaurants { get; set; }
    public int success { get; set; }
}

With that done we are ready start coding our windows phone app
create a windows phone app and add a ListBox as shown below

<ListBox  HorizontalAlignment="Left"  Name="dList" Height="391" Margin="10,43,0,0" VerticalAlignment="Top" Width="436">

That is all we need to add next we have to switch over to our C# file and start the real work, first we have to add our Newtonsoft.Json

using Newtonsoft.Json;

We then setup our WebClient call to our JSON API as follows

//Web client call to JSON API
            WebClient wClient = new WebClient();
            wClient.DownloadStringCompleted +=new DownloadStringCompletedEventHandler(wClient_Downloaded);
            wClient.DownloadStringAsync(new Uri("http://localhost/Police/get_all_locs.php"));

Paste the Restaurant and RootObject classes we got from json2csharp into the MainPage class; the next thing we have to is implement our DownLoadStringCompleted event argument in this case wClient_Downloaded

public void wClient_Downloaded(object sender, DownloadStringCompletedEventArgs e)
        {
            try 
            {
                var rootObj = JsonConvert.DeserializeObject(e.Result);
                foreach(var stationz in rootObj.location)
                {
                  dList.Items.Add(stationz.station_name);
                    
                    dList.Items.Add(stationz.longitude);

                    dList.Items.Add(stationz.latitude);
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show("Error>>>> "+ex);
            }
        }

You will notice will notice we had put the commands within the try, catch blocks to handle any exception and that is all you need to consume JSON.

Full C# code

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using Microsoft.Phone.Tasks;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using Microsoft.Phone.Controls;
using System.Device.Location;
using Microsoft.Phone.Controls.Maps;
using System.Windows.Media.Imaging;
using System.Windows.Controls.Primitives;
using System.ComponentModel;
using System.Collections;
using Newtonsoft.Json;

namespace PhoneApp4
{
    public partial class MainPage : PhoneApplicationPage
    {
        // Constructor
        public MainPage()
        {
            InitializeComponent();


            //Web client call to JSON API
            WebClient wClient = new WebClient();
            wClient.DownloadStringCompleted +=new DownloadStringCompletedEventHandler(wClient_Downloaded);
            wClient.DownloadStringAsync(new Uri("http://localhost/Police/get_all_locs.php"));

        }

        

        public void wClient_Downloaded(object sender, DownloadStringCompletedEventArgs e)
        {
            try 
            {
                var rootObj = JsonConvert.DeserializeObject(e.Result);
                foreach(var stationz in rootObj.location)
                {
                   dList.Items.Add(stationz.station_name);
                    
                    dList.Items.Add(stationz.longitude);
                    dList.Items.Add(stationz.latitude);
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show("Error>>>> "+ex);
            }
        }

 
        public class Location
        {
            public string pid { get; set; }
            public string longitude { get; set; }
            public string latitude { get; set; }
            public string created_at { get; set; }
            public string updated_at { get; set; }
            public string station_name { get; set; }
        }

        public class RootObject
        {
            public List location { get; set; }
            public int success { get; set; }
        }
    }
}

OUTPUT:

Android Accelerometer vs Windows Accelerometer part 2

We have accessed accelerometer readings on our android devices why don't we see how this is done on a windows phone development environment right quick and easy.

Create your windows phone project; NOTE this will work on a windows phone 7 device too so you can select the windows phone 7 emulator, as a matter of fact i will be running this on a wp7 emulator.

First we drag a TextBlock and name it readings(you can name it what ever) note i also changed my default text to 0.0, because i felt it way cooler...

<textblock horizontalalignment="Left" margin="79,106,0,0" name="reading" text="0.00" textwrapping="Wrap" verticalalignment="Top">
</textblock>

Next you need to add these references:

using Microsoft.Devices.Sensors;
using Microsoft.Xna.Framework;

If you can't find these references just right click references and select add references, you will get a list of references select those to.
We then have to create our Accelerometer variable

Accelerometer accelerometer;

with that setup the next thing we need to do is check if our device has an accelerometer sensor

if (!Accelerometer.IsSupported)
            {
                MessageBox.Show("No Accelerometer sensor found");
            }

now we have checked for our sensor and given the user a message if his device does not have an accelerometer, we then have to initialize our accelerometer variable, set the update/refresh time, create our event handler and then start our accelerometer see code below

if (accelerometer == null)
            {
                //initialize the accelerometer variable
                accelerometer = new Accelerometer();
                //set the update delay in milliseconds
                accelerometer.TimeBetweenUpdates = TimeSpan.FromMilliseconds(10);
                accelerometer.CurrentValueChanged += new EventHandler>(accelerometer_ValueChanged);
                //start our sensor
                accelerometer.Start();
            }

so if there is an accelerometer device and we are not getting any data (that is, if it is offline) then we do the above.
we then update our UI thread with the following code:

void accelerometer_ValueChanged(object sender, SensorReadingEventArgs e)
        {
            Dispatcher.BeginInvoke(() => UpdateUI(e.SensorReading));
        }

Great you have it this far, believe it or not we are getting our data from the accelerometer we for those with doubt why don't we display this data in our TextBlock through our UpdateUI method.

private void UpdateUI(AccelerometerReading accelerometerReading)
        {
            Vector3 acceleration = accelerometerReading.Acceleration;

            reading.Text = "X: " + acceleration.X.ToString() + "\nY:" + acceleration.Y.ToString() + "\nZ: " + acceleration.Z.ToString();
        }

You can now run and test the code in the emulator, if you don't know how this is done just run the code and click the double arrow button pointing towards the right you will see a new window with some tabs, select accelerometer tab and drag the orange circle in the middle of the virtual phone.
you should see your readings
Full Code

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using Microsoft.Phone.Controls;
using Microsoft.Devices.Sensors;
using Microsoft.Xna.Framework;

namespace PhoneApp3
{
    public partial class MainPage : PhoneApplicationPage
    {
        Accelerometer accelerometer;
        // Constructor
        public MainPage()
        {
            InitializeComponent();

            // Sample code to localize the ApplicationBar
            //BuildLocalizedApplicationBar();
            if (!Accelerometer.IsSupported)
            {
                MessageBox.Show("No Accelerometer");
            }
            if (accelerometer == null)
            {
                accelerometer = new Accelerometer();
                accelerometer.TimeBetweenUpdates = TimeSpan.FromMilliseconds(10);
                accelerometer.CurrentValueChanged += new EventHandler>(accelerometer_ValueChanged);
                accelerometer.Start();
            }

            
        }

        void accelerometer_ValueChanged(object sender, SensorReadingEventArgs e)
        {
            Dispatcher.BeginInvoke(() => UpdateUI(e.SensorReading));
        }

        private void UpdateUI(AccelerometerReading accelerometerReading)
        {
            Vector3 acceleration = accelerometerReading.Acceleration;

            reading.Text = "X: " + acceleration.X.ToString() + "\nY:" + acceleration.Y.ToString() + "\nZ: " + acceleration.Z.ToString();
       
    }
}

Our output