Building a resource ID as a string

Sample

Here's my strings.xml
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<resources>
    <string name="app_name">Scratch Pad</string>
    <string name="hello_world">Hello World!</string>
    <string name="text_1">text one</string>
    <string name="text_2">text two</string>
    <string name="text_3">text three</string>
    <string name="text_4">text four</string>
    <string name="text_5">text five</string>
</resources>

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Here's my activity_main.xml

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<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/text_view"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world"
        android:textSize="32sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</android.support.constraint.ConstraintLayout>

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and here's my MainActivity.java

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package com.example.android.scratchpad;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // I want to get the string named "text_2" from strings.xml
        int num = 2;

        // Here I'm building my ID as a string instead of hardcoding it like R.string.text_2
        String textID = "text_" + num;
        int resID = getResources().getIdentifier(textID, "string", getPackageName());

        // Now I'm grabbing the value of string "text_2" from strings.xml and putting it into changed_text
        String changed_text = (String) getText(resID);

        /**
         * Changing the "hello world" text in text_view to the value of changed_text
         */
        TextView textView = (TextView) findViewById(R.id.text_view);
        textView.setText(changed_text);
    }
}
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