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How to iterate a JSON Array in Android using Kotlin?
This example demonstrates how to iterate a JSON Array in 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" android:padding="8dp" tools:context=".MainActivity"> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerHorizontal="true" android:layout_marginTop="50dp" android:text="Tutorials Point" android:textAlignment="center" android:textColor="@android:color/holo_green_dark" android:textSize="32sp" android:textStyle="bold" /> <TextView android:id="@+id/textView" android:layout_width="wrap_content" android:layout_height="wrap_content" 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.JSONObject
@Suppress("NAME_SHADOWING")
class MainActivity : AppCompatActivity() {
private lateinit var textView: TextView
var strJson = ("{ \"Employee\" :[{\"ID\":\"01\",\"Name\":\"Sam\",\"Salary\":\"50000\"},"
+ "{\"ID\":\"02\",\"Name\":\"Shankar\",\"Salary\":\"60000\"}] }")
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
title = "KotlinApp"
textView = findViewById(R.id.textView)
val data = StringBuilder()
val jsonObject = JSONObject(strJson)
val jsonArray = jsonObject.optJSONArray("Employee")
for (i in 0 until jsonArray.length()) {
val jsonObject = jsonArray.getJSONObject(i)
val id = jsonObject.optString("ID").toInt()
val name = jsonObject.optString("Name")
val salary = jsonObject.optString("Salary").toFloat()
data.append("Employee ").append(i).append(" :
ID= ") .append(id).append("
" + "Name= ") .append(name).append("
Salary= ") .append(salary).append("
")
}
textView.text = data.toString()
}
}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="app.com.kotlipapp"> <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 −
Click here to download the project code.
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