This video gives details and demonstrates to create, retrieve or delete the shared preference variables as your Android App data.

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Complete source code and other details:

package com.programmerworld.sharedpreferenceapp;

import androidx.appcompat.app.AppCompatActivity;

import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    private TextView textView;
    private EditText editText;

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

        textView = findViewById(R.id.textView);
        editText = findViewById(R.id.editText);
    }


    public void buttonPut(View view){
        SharedPreferences sharedPreferences = getPreferences(MODE_PRIVATE);
        SharedPreferences.Editor editor = sharedPreferences.edit();

        editor.clear();
        editor.putString("stringUserData", editText.getText().toString());
        editor.putString("stringProgrammerWorld", "This is Programmer World");
        editor.apply();
    }

    public void buttonGet(View view){
        SharedPreferences sharedPreferences = getPreferences(MODE_PRIVATE);
        String stringSharedPref_UserData = sharedPreferences.getString("stringUserData", null);
        String stringSharedPref_PWorld = sharedPreferences.getString("stringProgrammerWorld", null);

        if (stringSharedPref_UserData == null &&
                stringSharedPref_PWorld == null){
            textView.setText("Shared Preference Variables do NOT exits");
        }
        else {
            textView.setText(stringSharedPref_PWorld + "\n" + stringSharedPref_UserData);
        }
    }

    public void buttonDeleteAll(View view){
        SharedPreferences sharedPreferences = getPreferences(MODE_PRIVATE);
        //removes all the shared preference variables
        sharedPreferences.edit().clear().commit();
    }

    public void buttonDelete(View view){
        SharedPreferences sharedPreferences = getPreferences(MODE_PRIVATE);
        // removes specific shared preference variable
        sharedPreferences.edit().remove("stringUserData").commit();
    }
}

<?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"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/textView"
        android:layout_width="303dp"
        android:layout_height="93dp"
        android:text="Hello World!"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.412"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.33" />

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="46dp"
        android:layout_marginTop="35dp"
        android:onClick="buttonPut"
        android:text="Put"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/editText" />

    <EditText
        android:id="@+id/editText"
        android:layout_width="268dp"
        android:layout_height="67dp"
        android:layout_marginStart="47dp"
        android:layout_marginTop="23dp"
        android:ems="10"
        android:hint="SharedPreferences Text ..."
        android:inputType="textPersonName"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="85dp"
        android:layout_marginTop="36dp"
        android:onClick="buttonGet"
        android:text="Get"
        app:layout_constraintStart_toEndOf="@+id/button"
        app:layout_constraintTop_toBottomOf="@+id/editText" />

    <Button
        android:id="@+id/button3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="42dp"
        android:layout_marginTop="40dp"
        android:onClick="buttonDeleteAll"
        android:text="Delete All"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView" />

    <Button
        android:id="@+id/button4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="78dp"
        android:layout_marginTop="40dp"
        android:onClick="buttonDelete"
        android:text="Delete"
        app:layout_constraintStart_toEndOf="@+id/button3"
        app:layout_constraintTop_toBottomOf="@+id/textView" />

</androidx.constraintlayout.widget.ConstraintLayout>

No changes required in Manifest, gradle or any other files.