Java tutorial
/* * Copyright (C) 2016 Google Inc. All Rights Reserved. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.google.android.apps.santatracker.games.cityquiz; import android.content.Context; import android.util.Log; import com.google.android.apps.santatracker.R; import com.google.android.gms.maps.model.LatLng; import com.google.maps.android.SphericalUtil; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.util.ArrayList; import java.util.Collections; import java.util.List; import java.util.Random; /** * Utility class to assist with loading city data into City Quiz Games. */ public class CityQuizUtil { private static final String TAG = CityQuizUtil.class.getSimpleName(); /** * Retrieve a random list of cities. * * @param amt Max number of cities to retrieve. * * @return Random list of cities. If amt is more than the amount of cities available, all cities are returned. */ public static List<City> getCities(Context context, int amt) { List<City> allCities = getCities(context); Collections.shuffle(allCities, new Random()); if (amt > allCities.size()) { amt = allCities.size(); } // Only return the cities that will be used in the game. List<City> cities = new ArrayList<>(); cities.addAll(0, allCities.subList(0, amt)); return cities; } private static List<City> getCities(Context context) { List<City> cities = new ArrayList<>(); JSONArray jCities = getCitiesFromFile(context); for (int i = 0; jCities != null && i < jCities.length(); i++) { try { JSONObject jCity = jCities.getJSONObject(i); double lat = jCity.getDouble("lat"); double lng = jCity.getDouble("lng"); String cityResourceName = jCity.getString("name"); int cityNameResourceId = context.getResources().getIdentifier(cityResourceName, "string", context.getPackageName()); String cityName; // Check if city name string resource is found. if (cityNameResourceId != 0) { // Use string resource for city name. cityName = context.getResources().getString(cityNameResourceId); } else { // Use default English city name. cityName = jCity.getString("default_name"); } String imageUrl = jCity.getString("image_name"); String imageAuthor = jCity.getString("image_author"); City city = new City(lat, lng, imageUrl, imageAuthor, cityName); cities.add(city); } catch (JSONException e) { Log.e(TAG, "Unable to get city from json, " + e); } } // Check if there are enough cities to set fake ones. if (cities.size() > 3) { // Set fake locations for each city. for (int i = 0; i < cities.size(); i++) { City city = cities.get(i); List<City> tempCities = new ArrayList<>(cities); // Sort tempCities in order of closest to the current city. Collections.sort(tempCities, new CityLocationComparator(city)); // Get the closest three cities, excluding the current city. List<City> closestCities = tempCities.subList(1, 4); Collections.shuffle(closestCities); // Choose the first two of the three cities from the closestCities list. city.setIncorrectLoaciton(City.FIRST_FAKE_INDEX, closestCities.get(0).getCorrectLocation()); city.setIncorrectLoaciton(City.SECOND_FAKE_INDEX, closestCities.get(1).getCorrectLocation()); } } return cities; } private static JSONArray getCitiesFromFile(Context context) { try { InputStream inputStream = context.getResources().openRawResource(R.raw.city_quiz_cities); BufferedReader r = new BufferedReader(new InputStreamReader(inputStream)); StringBuilder total = new StringBuilder(); String line; while ((line = r.readLine()) != null) { total.append(line).append('\n'); } JSONArray jsonArray = new JSONArray(total.toString()); return jsonArray; } catch (IOException e) { Log.e(TAG, "Unable to read city quiz json file, " + e); } catch (JSONException e) { Log.e(TAG, "Unable to parse city quiz json, " + e); } return null; } }