activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:orientation="vertical"
    tools:context=".MainActivity">

    <TextView android:id="@+id/textViewRaw"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_weight="1"
    android:gravity="center_horizontal|center_vertical"
        tools:ignore="MissingConstraints" />

    <TextView android:id="@+id/textViewAsset"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_weight="1" />

</LinearLayout>

MainActivity.java

package com.example.readingresourcefiles;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.widget.TextView;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        TextView textViewRaw = findViewById(R.id.textViewRaw);
        textViewRaw.setText(getText(this.getResources().openRawResource(R.raw.raw_text)));
        TextView textViewAsset = findViewById(R.id.textViewAsset);
        try {
            textViewAsset.setText(getText(this.getAssets().open("asset_text.txt")));
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private String getText(InputStream inputStream) {
        StringBuilder stringBuilder = new StringBuilder();
        try {
            if (inputStream != null) {
                InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
                BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
                String newLine = null;
                while ((newLine = bufferedReader.readLine()) != null) {
                    stringBuilder.append(newLine + "\n");
                }
                inputStream.close();
            }
        } catch (java.io.IOException e) {
            e.printStackTrace();
        }
        return stringBuilder.toString();
    }
}