MainActivity.java package com.blogspot.csdevbin.sharedpreferences; import android.content.Context; 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; import android.widget.Toast; public class MainActivity extends AppCompatActivity {     EditText food , shopping , fuel , telephone ;     TextView previousExpense ;     SharedPreferences sharedPreferences ;     @Override     protected void onCreate(Bundle savedInstanceState) {         super .onCreate(savedInstanceState);         setContentView(R.layout. activity_main );          food = (EditText)findViewById(R.id. etfood );          shopping = (EditText)findViewById(R.id. edShopping );          fuel = (EditText)findViewById(R.id. edFuel );          telephone = (EditTex