Kotlin Android XMLPullParser Tutorial

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 parsers are:

DOM Parser
SAX Parser
XMLPullParser

Android recommends to use XMLPullParser to parse the XML file rather than SAX and DOM because it is fast.

The org.xmlpull.v1.XmlPullParser interface provides the functionality to parse the XML document using XMLPullParser.

Events of XmlPullParser

The next() method of XMLPullParser moves the cursor pointer to the next event. Generally, we use four constants (works as the event) defined in the XMLPullParser interface.

START_TAG: An XML start tag will read.
TEXT: Text content was read the text content can be retrieved using the getText() method.
END_TAG: An end tag will read.
END_DOCUMENT: No more events are available.

Example of XML Parsing using XMLPullParser

In this example, we read the XML data and bind them into a ListView using XMLPullParser.

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.kotlinxmlparsingusingxmlpullparser.MainActivity”>        <ListView          android:id=”@+id/listView”          android:layout_width=”match_parent”          android:layout_height=”wrap_content” >        </ListView>    </android.support.constraint.ConstraintLayout>  

employees.xml

Create the XML document employees.xml in assets directory to parse the data using XMLPullParser.

  <?xml version=”1.0″ encoding=”UTF-8″?>  <employees>      <employee>          <id>1</id>          <name>Sachin Kumar</name>          <salary>50000</salary>      </employee>      <employee>          <id>2</id>          <name>Rahul Kumar</name>          <salary>60000</salary>      </employee>      <employee>          <id>3</id>          <name>John Mike</name>          <salary>70000</salary>      </employee>      <employee>          <id>4</id>          <name>Ajay Kumar</name>          <salary>45000</salary>      </employee>      <employee>          <id>5</id>          <name>Toni Nayer</name>          <salary>55000</salary>      </employee>      <employee>          <id>6</id>          <name>Mr Bony</name>          <salary>42000</salary>      </employee>      <employee>          <id>7</id>          <name>Raj Kumar</name>          <salary>30000</salary>      </employee>      <employee>          <id>8</id>          <name>Rahul Kumar</name>          <salary>60000</salary>      </employee>      <employee>          <id>9</id>          <name>John Mike</name>          <salary>70000</salary>      </employee>      <employee>          <id>10</id>          <name>Sachin Kumar</name>          <salary>50000</salary>      </employee>      <employee>          <id>11</id>          <name>Rahul Kumar</name>          <salary>60000</salary>      </employee>      <employee>          <id>12</id>          <name>John Mike</name>          <salary>70000</salary>      </employee>  </employees>  

Employee.kt

Create a data model class Employee.kt corresponds to the XML data file.

  package example.tutoraspire.com.kotlinxmlparsingusingxmlpullparser    class Employee {      var id: Int = 0      var name: String? = null      var salary: Float = 0.toFloat()        override fun toString(): String {          return ” Id = $idn Name = $namen Salary = $salary”      }  }  

XmlPullParserHandler.kt

Write the code to parse the XML file using XMLPullParser. In this class, we return all the employees in the list.

  package example.tutoraspire.com.kotlinxmlparsingusingxmlpullparser    import org.xmlpull.v1.XmlPullParserException  import org.xmlpull.v1.XmlPullParser  import org.xmlpull.v1.XmlPullParserFactory  import java.io.IOException  import java.io.InputStream    class XmlPullParserHandler {      private val employees = ArrayList<Employee>()      private var employee: Employee? = null      private var text: String? = null        fun parse(inputStream: InputStream): List<Employee> {          try {              val factory = XmlPullParserFactory.newInstance()              factory.isNamespaceAware = true              val parser = factory.newPullParser()              parser.setInput(inputStream, null)              var eventType = parser.eventType              while (eventType != XmlPullParser.END_DOCUMENT) {                  val tagname = parser.name                  when (eventType) {                      XmlPullParser.START_TAG -> if (tagname.equals(“employee”, ignoreCase = true)) {                          // create a new instance of employee                          employee = Employee()                      }                      XmlPullParser.TEXT -> text = parser.text                      XmlPullParser.END_TAG -> if (tagname.equals(“employee”, ignoreCase = true)) {                          // add employee object to list                          employee?.let { employees.add(it) }                      } else if (tagname.equals(“id”, ignoreCase = true)) {                          employee!!.id = Integer.parseInt(text)                      } else if (tagname.equals(“name”, ignoreCase = true)) {                          employee!!.name = text                      } else if (tagname.equals(“salary”, ignoreCase = true)) {                          employee!!.salary = java.lang.Float.parseFloat(text)                      }                        else -> {                      }                  }                  eventType = parser.next()              }            } catch (e: XmlPullParserException) {              e.printStackTrace()          } catch (e: IOException) {              e.printStackTrace()          }          return employees      }  }  

MainActivity.kt

In this class, we send XML data into ArrayAdapter and bind them into ListView.

  package example.tutoraspire.com.kotlinxmlparsingusingxmlpullparser    import android.support.v7.app.AppCompatActivity  import android.os.Bundle  import android.widget.ArrayAdapter  import android.widget.ListView  import java.io.IOException       class MainActivity : AppCompatActivity() {        override fun onCreate(savedInstanceState: Bundle?) {          super.onCreate(savedInstanceState)           setContentView(R.layout.activity_main)          val listView = findViewById<ListView>(R.id.listView)          var employees: List<Employee>? = null           try {              val parser = XmlPullParserHandler()              val istream = assets.open(“employees.xml”)              employees = parser.parse(istream)                val adapter = ArrayAdapter(this, android.R.layout.simple_list_item_1, employees)              listView.adapter = adapter            } catch (e: IOException) {              e.printStackTrace()          }      }  }  

Output:

Next Topic#

Kotlin Android XMLPullParser Tutorial

Kotlin Android XMLPullParser Tutorial

Events of XmlPullParser

Example of XML Parsing using XMLPullParser

activity_main.xml

employees.xml

Employee.kt

XmlPullParserHandler.kt

MainActivity.kt

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