How to read files from assets on Android using Kotlin?

This example demonstrates how to read files from assets 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.

Example

<?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:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:layout_marginTop="100dp"
   android:layout_centerHorizontal="true"
   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="match_parent"
   android:layout_height="wrap_content"
   android:layout_centerInParent="true"
   android:padding="24sp"
   android:textAlignment="center"
   android:textColor="@android:color/holo_purple"
   android:textStyle="bold" />
<Button
   android:id="@+id/btnReadText"
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:layout_alignParentBottom="true"
   android:layout_centerInParent="true"
   android:layout_marginBottom="30dp"
   android:text="Read text from assets"
   android:textStyle="bold" />
</RelativeLayout>

Step 3 − Right click app >> New >> Folder >> Assets folder. Right click on the assets folder, select New >> file (myText.txt) and your text.

Step 4 − Add the following code to src/MainActivity.kt

import android.os.Bundle
import android.widget.Button
import android.widget.TextView
import androidx.appcompat.app.AppCompatActivity
import java.io.IOException
import java.io.InputStream
class MainActivity : AppCompatActivity() {
   private lateinit var button: Button
   private lateinit var textView: TextView
   override fun onCreate(savedInstanceState: Bundle?) {
      super.onCreate(savedInstanceState)
      setContentView(R.layout.activity_main)
      title = "KotlinApp"
      textView = findViewById(R.id.textView)
      button = findViewById(R.id.btnReadText)
      button.setOnClickListener {
         var string: String? = ""
         try {
            val inputStream: InputStream = assets.open("myText.txt")
            val size: Int = inputStream.available()
            val buffer = ByteArray(size)
            inputStream.read(buffer)
            string = String(buffer)
         } catch (e: IOException) {
            e.printStackTrace()
         }
         textView.text = string
      }
   }
}

Step 5 − 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