shared preferences in android

package com.example.viraj.sharedpreferences;

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

public class MainActivity extends AppCompatActivity {
    private Button savebutton;
    private EditText entertext;
    private TextView resultdisplay;
    private SharedPreferences myPref;
//information isme store kart he iss liy create kiya
    private static final String PREF_NAME = "MY_PREF_FILE";

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

        savebutton = (Button) findViewById(R.id.id_savedata);
        entertext = (EditText) findViewById(R.id.id_entersomething);
        resultdisplay = (TextView) findViewById(R.id.id_resulttextview);

        savebutton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                myPref = getSharedPreferences(PREF_NAME, 0);
                SharedPreferences.Editor editor = myPref.edit();
//editor liya our save kiya
                editor.putString("key_messgae_ki_he", entertext.getText().toString());
                //save commit
                editor.commit();

            }
        });
//get data back
        SharedPreferences pref = getSharedPreferences(PREF_NAME, 0);//level o he
        if (pref.contains("key_messgae_ki_he")) {
            String message = pref.getString("key_messgae_ki_he", "not found");
            resultdisplay.setText("MESSAGE" + message);
        }

    }
}

<?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="com.example.viraj.sharedpreferences.MainActivity">

    <EditText
        android:id="@+id/id_entersomething"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="48dp"
        android:ems="10"
        android:hint="ENTER SOMETHING"
        android:inputType="textPersonName"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.503"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/id_savedata"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="52dp"
        android:text="Button"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/id_entersomething" />

    <TextView
        android:id="@+id/id_resulttextview"
        android:layout_width="252dp"
        android:layout_height="28dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="60dp"
        android:text="TextView"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/id_savedata" />

    <RatingBar
        android:id="@+id/ratingBar"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
</android.support.constraint.ConstraintLayout>