How to parse JSON on Android using Kotlin?

This example demonstrates how to parse JSON on Android using Kotlin

Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.

Step 2 − Add the following code to res/layout/activity_main.xml.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:tools="http://schemas.android.com/tools"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   tools:context=".MainActivity">
   <TextView
      android:id="@+id/text2"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_centerHorizontal="true"
      android:layout_marginTop="70dp"
      android:background="#008080"
      android:padding="5dp"
      android:text="TutorialsPoint"
      android:textColor="#fff"
      android:textSize="24sp"
      android:textStyle="bold" />
   <TextView
      android:textColor="@android:color/background_dark"
      android:id="@+id/textViewName"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_centerInParent="true"
      android:textSize="16sp"
      android:textStyle="bold|italic" />
   <TextView
      android:id="@+id/textViewSal"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_below="@+id/textViewName"
      android:layout_centerInParent="true"
      android:textColor="@android:color/background_dark"
      android:textSize="16sp"
      android:textStyle="bold" />
</RelativeLayout>

Step 3 − Add the following code to src/MainActivity.kt

import android.os.Bundle
import android.widget.TextView
import androidx.appcompat.app.AppCompatActivity
import org.json.JSONException
import org.json.JSONObject
class MainActivity : AppCompatActivity() {
   lateinit var textViewName: TextView
   lateinit var textViewSal: TextView
   var jsonString = "{"employee":{"name":"tutorialspoint","salary":65000}}"
   lateinit var name:String
   lateinit var salary:String
   override fun onCreate(savedInstanceState: Bundle?) {
      super.onCreate(savedInstanceState)
      setContentView(R.layout.activity_main)
      title = "KotlinApp"
      textViewName = findViewById(R.id.textViewName)
      textViewSal = findViewById(R.id.textViewSal)
      try {
         // get JSONObject from JSON file
         val obj = JSONObject(jsonString)
         // fetch JSONObject named employee
         val employee: JSONObject = obj.getJSONObject("employee")
         // get employee name and salary
         name = employee.getString("name")
         salary = employee.getString("salary")
         // set employee name and salary in TextView's
         textViewName.text = "Name: $name"
         textViewSal.text = "Salary: $salary"
      } catch (e: JSONException) {
         e.printStackTrace()
      }
   }
}

Step 4 − Add the following code to androidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
   package="com.example.q11">
   <application
      android:allowBackup="true"
      android:icon="@mipmap/ic_launcher"
      android:label="@string/app_name"
      android:roundIcon="@mipmap/ic_launcher_round"
      android:supportsRtl="true"
      android:theme="@style/AppTheme">
      <activity android:name=".MainActivity">
         <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
         </intent-filter>
      </activity>
   </application>
</manifest>

Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from android studio, open one of your project's activity files and click the Run icon  from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen.