strings.xml

<string name="title">Shared Preferences</string> 
<string name="save_data">Save</string>
<string name="load_data">Retrieve</string>
<string name="saved_name">Your name</string> 
<string name="enter_name">Enter your name</string> 
<string name="save">Save</string>
<string name="show">Show</string>


activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" >
    <TextView
        android:id="@+id/title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="16dp"
        android:text="@string/title"
        android:textSize="20sp"
        android:textStyle="bold" />
        
    <TextView android:id="@+id/data_to_save" 
        android:layout_width="wrap_content" 
        android:layout_height="wrap_content" 
        android:layout_alignParentLeft="true" 
        android:layout_below="@+id/title" 
       android:layout_marginLeft="23dp" 
       android:layout_marginTop="63dp" 
       android:textSize="20sp" 
       android:text="@string/save_data" />
       
    <EditText
        android:id="@+id/enter_data"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" 
        android:layout_below="@+id/title" 
        android:layout_marginLeft="20dp" 
        android:layout_marginRight="15dp" 
        android:layout_marginTop="55dp" 
        android:gravity="left|top" 
        android:layout_toRightOf="@id/data_to_save" 
        android:hint="@string/enter_name" />
    <Button
        android:id="@+id/save" 
        android:layout_width="wrap_content" 
        android:layout_height="wrap_content" 
        android:layout_below="@+id/data_to_save" 
        android:layout_marginLeft="25dp" 
        android:layout_marginTop="66dp" 
        android:text="@string/save" />
        
    <TextView android:id="@+id/data_to_load" 
        android:layout_width="wrap_content" 
        android:layout_height="wrap_content" 
        android:layout_alignParentLeft="true" 
        android:layout_below="@+id/save" 
        android:layout_marginLeft="23dp" 
        android:layout_marginTop="63dp" 
        android:text="@string/load_data" 
        android:textSize="20sp"/>
        
    <Button
        android:id="@+id/show" 
        android:layout_width="wrap_content" 
        android:layout_height="wrap_content" 
        android:layout_below="@+id/data_to_load" 
        android:layout_marginLeft="25dp" 
        android:layout_marginTop="36dp" 
        android:text="@string/show" />
        
    <EditText
        android:id="@+id/load_data" 
        android:layout_width="fill_parent" 
        android:layout_height="wrap_content" 
        android:layout_below="@+id/save" 
        android:hint="@string/saved_name" 
        android:layout_toRightOf="@+id/data_to_load" 
        android:layout_alignBottom="@+id/data_to_load" 
        android:layout_marginLeft="20dp" 
        android:layout_marginTop="40dp" />

</RelativeLayout>

main_activity.java


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

public class MainActivity extends Activity implements View.OnClickListener {
    private EditText saveData;
    private TextView retrieveData;
    private Button saveBtn;
    private Button showBtn;

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

        retrieveData = (TextView)findViewById(R.id.load_data);
        saveData = (EditText)findViewById(R.id.enter_data);
        saveBtn = (Button)findViewById(R.id.save);
        showBtn = (Button)findViewById(R.id.show);
        saveBtn.setOnClickListener(this);
        showBtn.setOnClickListener(this);
        showBtn.setEnabled(false);
        if(retrieveName().length()>0)
        showBtn.setEnabled(true);
    }
    @Override
    public void onClick(View v) { 
    switch(v.getId()) {
        case R.id.save:
            saveName("name", saveData.getText().toString());
            showBtn.setEnabled(true);
            break;
        case R.id.show:
            retrieveData.setText(retrieveName());
            break; }
    }
    private void saveName(String key, String value){
        SharedPreferences sharedPreferences = getPreferences(MODE_PRIVATE);
        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.putString(key, value);
        editor.commit();
    }
    private String retrieveName(){
        SharedPreferences sharedPreferences = getPreferences(MODE_PRIVATE);
        String savedData = sharedPreferences.getString("name", "");
        return savedData;
    }
}