Kotlin Android XML Parsing using DOM Parser

XML document is commonly used to share the data on the internet. The data provided in XML format are able to update frequently and parsing them is a common task for network-based apps.

In Android, there are three types of XML parsers to parse the XML data and read them in android applications, these are:

Android DOM (Document Object Model) parser uses an object-based approach to create and parse the XML files in android applications. The DOM parser loads the XML file into memory to parse the XML document. Due to this reason, it consumes more memory.

Example of XML Parsing using DOM Parser

In this example, we parse XML data and display them into ListView.

activity_main.xml

Add the ListView in the activity_main.xml layout.

  <?xml version=”1.0″ encoding=”utf-8″?>  <android.support.constraint.ConstraintLayout xmlns:android=”http://schemas.android.com/apk/res/android”      xmlns:app=”http://schemas.android.com/apk/res-auto”      xmlns:tools=”http://schemas.android.com/tools”      android:layout_width=”match_parent”      android:layout_height=”match_parent”      tools:context=”example.tutoraspire.com.kotlinxmlparsingusingdomparser.MainActivity”>        <ListView              android:id=”@+id/listView”              android:layout_width=”match_parent”              android:layout_height=”match_parent”>       </ListView>  </android.support.constraint.ConstraintLayout>  

empdetail.xml

Create the XML document empdetail.xml in assets directory to parse the data using DOM parser.

  <?xml version=”1.0″ encoding=”utf-8″?>  <records>      <employee>          <name>Sachin Kumar</name>          <salary>50000</salary>          <designation>Developer</designation>      </employee>      <employee>          <name>Rahul Kumar</name>          <salary>60000</salary>          <designation>Team Leader</designation>      </employee>      <employee>          <name>John Mike</name>          <salary>70000</salary>          <designation>Manager</designation>      </employee>      <employee>          <name>Ajay Kumar</name>          <salary>45000</salary>          <designation>Developer</designation>      </employee>      <employee>          <name>Toni Nayer</name>          <salary>55000</salary>          <designation>Marketing</designation>      </employee>      <employee>          <name>Mr Bony</name>          <salary>42000</salary>          <designation>Sales</designation>      </employee>      <employee>          <name>Raj Kumar</name>          <salary>30000</salary>          <designation>Production</designation>      </employee>      <employee>          <name>Rahul Kumar</name>          <salary>60000</salary>          <designation>Team Leader</designation>      </employee>      <employee>          <name>John Mike</name>          <salary>70000</salary>          <designation>Manager</designation>      </employee>      <employee>          <name>Sachin Kumar</name>          <salary>50000</salary>          <designation>Developer</designation>      </employee>      <employee>          <name>Rahul Kumar</name>          <salary>60000</salary>          <designation>Team Leader</designation>      </employee>      <employee>          <name>John Mike</name>          <salary>70000</salary>          <designation>Manager</designation>      </employee>  </records>  

custom_list.xml

Create a custom layout to display the list of data into ListView.

  <?xml version=”1.0″ encoding=”utf-8″?>  <LinearLayout xmlns:android=”http://schemas.android.com/apk/res/android”      xmlns:app=”http://schemas.android.com/apk/res-auto”      android:layout_width=”match_parent”      android:layout_height=”match_parent”      android:orientation=”horizontal”>      <LinearLayout          android:layout_width=”match_parent”          android:layout_height=”wrap_content”          android:layout_weight=”1″          android:orientation=”vertical”>            <TextView              android:id=”@+id/name”              android:layout_width=”match_parent”              android:layout_height=”wrap_content”              android:text=”name”              android:textStyle=”bold”              android:layout_marginLeft=”15dp”              android:layout_marginStart=”15dp”              android:textAppearance=”@style/Base.TextAppearance.AppCompat.Medium” />            <TextView              android:id=”@+id/salary”              android:layout_width=”match_parent”              android:layout_height=”wrap_content”              android:text=”salary”              android:layout_marginLeft=”15dp”              android:layout_marginStart=”15dp”              android:layout_marginTop=”5dp”              android:textSize=”16sp”/>          <TextView              android:id=”@+id/designation”              android:layout_width=”match_parent”              android:layout_height=”wrap_content”              android:text=”designation”              android:layout_marginLeft=”15dp”              android:layout_marginStart=”15dp”              android:layout_marginTop=”5dp”              android:textSize=”16sp”/>      </LinearLayout>  </LinearLayout>  

MainActivity.kt

Add the following code to read and parse the XML data using DOM parser. Create the instance of DocumentBuilderFactory, DocumentBuilder and Document objects.

The HashMap<String, String> is used to read the data from XML document and add them into ArrayList().

  package example.tutoraspire.com.kotlinxmlparsingusingdomparser    import android.support.v7.app.AppCompatActivity  import android.os.Bundle  import android.widget.ListView  import android.widget.SimpleAdapter  import org.w3c.dom.Element  import org.w3c.dom.Node  import org.xml.sax.SAXException  import java.io.IOException  import javax.xml.parsers.DocumentBuilderFactory  import javax.xml.parsers.ParserConfigurationException    class MainActivity : AppCompatActivity() {      var empDataHashMap = HashMap<String, String>()      var empList: ArrayList<HashMap<String, String>> = ArrayList()      override fun onCreate(savedInstanceState: Bundle?) {          super.onCreate(savedInstanceState)          setContentView(R.layout.activity_main)          try {              val lv = findViewById<ListView>(R.id.listView)              val istream = assets.open(“empdetail.xml”)              val builderFactory = DocumentBuilderFactory.newInstance()              val docBuilder = builderFactory.newDocumentBuilder()              val doc = docBuilder.parse(istream)  //reading the tag “employee” of empdetail file              val nList = doc.getElementsByTagName(“employee”)              for (i in 0 until nList.getLength()) {                  if (nList.item(0).getNodeType().equals(Node.ELEMENT_NODE) ) {                //creating instance of HashMap to put the data of node value              empDataHashMap = HashMap()                      val element = nList.item(i) as Element                      empDataHashMap.put(“name”, getNodeValue(“name”, element))                      empDataHashMap.put(“salary”, getNodeValue(“salary”, element))                      empDataHashMap.put(“designation”, getNodeValue(“designation”, element))    //adding the HashMap data to ArrayList                      empList.add(empDataHashMap)                  }              }              val adapter = SimpleAdapter(this@MainActivity, empList, R.layout.custom_list, arrayOf(“name”, “salary”, “designation”), intArrayOf(R.id.name, R.id.salary, R.id.designation))              lv.setAdapter(adapter)          } catch (e: IOException) {              e.printStackTrace()          } catch (e: ParserConfigurationException) {              e.printStackTrace()          } catch (e: SAXException) {              e.printStackTrace()          }        }      // function to return node value      protected fun getNodeValue(tag: String, element: Element): String {          val nodeList = element.getElementsByTagName(tag)          val node = nodeList.item(0)          if (node != null) {              if (node.hasChildNodes()) {                  val child = node.getFirstChild()                  while (child != null) {                      if (child.getNodeType() === Node.TEXT_NODE) {                          return child.getNodeValue()                      }                  }              }          }          return “”      }  }  

Output:

Kotlin Android XML Parsing using DOM Parser

Next Topic#

Kotlin Android XML Parsing using DOM Parser

Kotlin Android XML Parsing using DOM Parser

Example of XML Parsing using DOM Parser

activity_main.xml

empdetail.xml

custom_list.xml

MainActivity.kt

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