android kotlin - Volley UTF-8 encoding example

MainActivity.kt

package com.cfsuman.kotlintutorials

import android.app.Activity
import android.os.Bundle
import android.text.method.ScrollingMovementMethod
import android.widget.*
import com.android.volley.Request


class MainActivity : Activity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        // get the widgets reference from XML layout
        val button = findViewById<Button>(R.id.button)
        val textView = findViewById<TextView>(R.id.textView)

        // Make text view content scrollable
        textView.movementMethod = ScrollingMovementMethod()

        // Feed Url
        val url = "https://www.kalerkantho.com/rss.xml"


        // Run volley
        button.setOnClickListener {
            // Disable the button itself
            it.isEnabled = false

            val stringRequest = VolleyUTF8EncodingStringRequest(
                Request.Method.GET,url,
                { response ->
                    textView.text = response
                }, { error ->
                    textView.text = error.toString()
                })

            // Add the volley string request to the request queue
            VolleySingleton.getInstance(this)
                .addToRequestQueue(stringRequest)
        }
    }
}

VolleyUTF8EncodingStringRequest.kt

package com.cfsuman.kotlintutorials

import com.android.volley.NetworkResponse
import com.android.volley.ParseError
import com.android.volley.Request
import com.android.volley.Response
import com.android.volley.toolbox.HttpHeaderParser
import java.io.UnsupportedEncodingException


// Volley custom string request with utf-8 encoding
class VolleyUTF8EncodingStringRequest(
    method: Int,
    url: String,
    private val mListener: Response.Listener<String>,
    errorListener: Response.ErrorListener
) : Request<String>(method, url, errorListener) {

    override fun deliverResponse(response: String) {
        mListener.onResponse(response)
    }

    override fun parseNetworkResponse(
        response: NetworkResponse): Response<String> {
        var parsed = ""

        val encoding = charset(
            HttpHeaderParser.parseCharset(response.headers))

        try {
            parsed = String(response.data, encoding)
            val bytes = parsed.toByteArray(encoding)
            parsed = String(bytes, charset("UTF-8"))

            return Response.success(
                parsed,
                HttpHeaderParser.parseCacheHeaders(response)
            )
        } catch (e: UnsupportedEncodingException) {
            return Response.error(ParseError(e))
        }
    }
}

VolleySingleton.kt

package com.cfsuman.kotlintutorials

import android.content.Context
import com.android.volley.Request
import com.android.volley.RequestQueue
import com.android.volley.toolbox.Volley

class VolleySingleton constructor(context: Context) {
    companion object {
        @Volatile
        private var INSTANCE: VolleySingleton? = null
        fun getInstance(context: Context) =
            INSTANCE ?: synchronized(this) {
                INSTANCE ?: VolleySingleton(context).also {
                    INSTANCE = it
                }
            }
    }
    private val requestQueue: RequestQueue by lazy {
        // applicationContext is key, it keeps you from leaking the
        // Activity or BroadcastReceiver if someone passes one in.
        Volley.newRequestQueue(context.applicationContext)
    }
    fun <T> addToRequestQueue(req: Request<T>) {
        requestQueue.add(req)
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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"
    android:background="#DCDCDC"
    android:padding="24dp">

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Run Volley"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:layout_marginTop="16dp"
        android:fontFamily="sans-serif"
        android:textSize="24sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/button"
        tools:text="TextView" />

</androidx.constraintlayout.widget.ConstraintLayout>

gradle dependencies

// Volley network library
implementation 'com.android.volley:volley:1.2.1'