SharedData.java

package com.SydneyMinyanimAndroid;

import android.content.SharedPreferences;
import com.google.common.reflect.TypeToken;
import com.google.gson.Gson;

import java.lang.reflect.Type;
import java.util.ArrayList;

class SharedData {

    void saveList(ArrayList<String> list, String key){
        SharedPreferences.Editor editor = MainActivity.prefs.edit();
        Gson gson = new Gson();
        String json = gson.toJson(list);
        editor.putString(key, json);
        editor.apply();
    }

    void loadList(String key){
        Gson gson = new Gson();
        String json = MainActivity.prefs.getString(key, null);
        Type type = new TypeToken<ArrayList<String>>() {}.getType();
        MainActivity.favouriteList = gson.fromJson(json, type);
    }
}