Unity - XML PARSING IN UNITY

Step 1 XML

XML (eXtensible Markup Language) is a markup language which is designed to transport and store data.

XML is most common tool for data transmission between applications.

XML data is stored in plain text format that provides a software and hardware independent way of storing data.

XML is very useful when we want to exchange data between incompatible systems over network.

Step 2 Use Of XML

Here are basic uses of XML:

• As Database: XML is really an interesting file that we can use as database in which we can store a set of data.
• Web Publishing: XML allows the developers to save the data into XML files and the use the XSLT transformation API's to generate the content in required format such as HTML, XHTML or WML.
• Web Searching: In our application we can use the XML data and then the search the data from the XML file and display to the user. Similar data can be displayed in different format to the user.
• Data transfer: We can use XML to save configuration or business data for our application. The XML file can be stored, used, transferred to another program.
• e-business applications: XML is ideal solution for Electronic Data Interchange (EDI).
• Metadata applications: In many applications, XML file is used as Metadata.
• Create other Languages: Many languages are created using XML. Examples are WML, MathML etc.
• Use in Databases: Modern database such as Oracle and MSSQL server is providing the XML support in their databases.

Step 3 XML Document

XML documents use a self-describing and simple syntax. First line in xml document is XML declaration; it defines XML version and encoding type. Second line describes the root element (Players) of the document and next line is its child element(Player).

<!--?xml version=”1.0” encoding=”UTF-8”?-->
 
 
Player1
10

3.1 Different Entities

Basically XML Document has following entities:

Step 4 Example

The following simple c# code demonstrate the XMLParsing with the help of XmlDocument and XmlElement classes.

Screenshots:

1) When XML file is initially read, following data will be displayed. 

2) By tapping Create Element button, element will be added as shown below. 

3) By tapping Modify Element button, elements will be modified as shown below. 

4.1 XMLParsing Script

using UnityEngine;
using System.Collections;
using System.Xml;
using System.Collections.Generic;
 
public class XMLParsing : MonoBehaviour
{
    public TextMesh fileDataTextbox;
    private string path;
    private string fileInfo;
    private XmlDocument xmlDoc;
    private WWW www;
    private TextAsset textXml;
    private List<Player> Players;
    private string fileName;
 
    // Structure for mainitaing the player information
    struct Player
    {
        public int Id;
        public string name;
        public int score;
    };
 
    void Awake()
    {
        fileName = "DemoXmlFile";
        Players = new List<Player>(); // initalize player list
        fileDataTextbox.text = "";
    }
    
    void Start ()
    {
        loadXMLFromAssest();
        readXml();
    }
    // Following method load xml file from resouces folder under Assets
    private void loadXMLFromAssest()
    {
        xmlDoc = new XmlDocument();
        if(System.IO.File.Exists(getPath()))
        {
            xmlDoc.LoadXml(System.IO.File.ReadAllText(getPath()));
        }
        else
        {
            textXml = (TextAsset)Resources.Load(fileName, typeof(TextAsset));
            xmlDoc.LoadXml(textXml.text);
        }
    }
    
    void Update()
    {
        // Following code just check whether any button is touched on mouse down
        if(Input.GetMouseButtonDown(0))
        {
            Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
            RaycastHit hit;
            if(Physics.Raycast(ray, out hit) && hit.collider != null)
            {
                if(hit.collider.name.Equals("ModifyXmlButton"))
                    modifyXml();
                else if(hit.collider.name.Equals("CreateElementButton"))
                    createElement();
            }
        }
    }
    // Following method reads the xml file and display its content
    private void readXml()
    {
        foreach(XmlElement node in xmlDoc.SelectNodes("Players/Player"))
        {
            Player tempPlayer = new Player();
            tempPlayer.Id = int.Parse(node.GetAttribute("id"));
            tempPlayer.name = node.SelectSingleNode("name").InnerText;
            tempPlayer.score = int.Parse(node.SelectSingleNode("score").InnerText);
            Players.Add(tempPlayer);
            displayPlayeData(tempPlayer);
        }
    }
    private void displayPlayeData(Player tempPlayer)
    {
        fileDataTextbox.text += tempPlayer.Id + "\t\t" + tempPlayer.name + "\t\t" + tempPlayer.score + "\n";
    }
 
    // Following method will be called by tapping ModifyXml button
    // It just multiply player's score by 10
    private void modifyXml()
    {
        fileDataTextbox.text = "";
        foreach(XmlElement node in xmlDoc.SelectNodes("Players/Player"))
        {
            int nodeId = int.Parse(node.GetAttribute("id"));
            Player tempPlayer = Players[nodeId-1];
            tempPlayer.score *= 10;
            Players[nodeId-1] = tempPlayer;
            node.SelectSingleNode("score").InnerText = tempPlayer.score + "";
            displayPlayeData(tempPlayer);
        }
        xmlDoc.Save(getPath()+".xml");
    }
 
    // Following method create new element of player
    private void createElement()
    {
        Player tempPlayer = new Player();
        tempPlayer.Id = Players.Count+1;
        tempPlayer.name = "Player"+tempPlayer.Id;
        tempPlayer.score = tempPlayer.Id*10;
        Players.Add(tempPlayer);
        displayPlayeData(tempPlayer);
 
        XmlNode parentNode = xmlDoc.SelectSingleNode("Players");
        XmlElement element = xmlDoc.CreateElement("Player");
        element.SetAttribute("id",tempPlayer.Id.ToString());
        element.AppendChild(createNodeByName("name",tempPlayer.name));
        element.AppendChild(createNodeByName("score",tempPlayer.score.ToString()));
        parentNode.AppendChild(element);
        xmlDoc.Save(getPath()+".xml");
    }
    private XmlNode createNodeByName(string name, string innerText)
    {
        XmlNode node = xmlDoc.CreateElement(name);
        node.InnerText = innerText;
        return node;
    }
 
    // Following method is used to retrive the relative path as device platform
    private string getPath(){
        #if UNITY_EDITOR
        return Application.dataPath +"/Resources/"+fileName;
        #elif UNITY_ANDROID
        return Application.persistentDataPath+fileName;
        #elif UNITY_IPHONE
        return GetiPhoneDocumentsPath()+"/"+fileName;
        #else
        return Application.dataPath +"/"+ fileName;
        #endif
    }
    private string GetiPhoneDocumentsPath()
    {
        // Strip "/Data" from path
        string path = Application.dataPath.Substring(0, Application.dataPath.Length - 5);
        // Strip application name
        path = path.Substring(0, path.LastIndexOf('/'));
        return path + "/Documents";
    }
}

For any query or suggestions please comment below. Click here to Download demo from github.

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Swati Patel

I am professional Game Developer, developing games in cocos2d(for iOS) and unity(for all platforms). Games are my passion and I aim to create addictive, high quality games. I have been working in this field since 1 year.