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.doodles.shared; import android.content.Context; import android.os.AsyncTask; import android.util.Log; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.UnsupportedEncodingException; import org.json.JSONException; import org.json.JSONObject; /** * Maintains the history and stats of what the user has accomplished. * * <p>Note that this class handles the serializing into JSON instead of each game. This was done * to make it easier to make a game picker that showed your status on each game. Since there are * canonical types it would then know how to read them. We add a setArbitraryData and * getArbitaryData for any game that wants to put other kind of information in. */ public class HistoryManager { private static final String TAG = HistoryManager.class.getSimpleName(); public static final String BEST_PLACE_KEY = "place"; public static final String BEST_STAR_COUNT_KEY = "stars"; public static final String BEST_TIME_MILLISECONDS_KEY = "time"; public static final String BEST_SCORE_KEY = "score"; public static final String BEST_DISTANCE_METERS_KEY = "distance"; public static final String ARBITRARY_DATA_KEY = "arb"; private static final String FILENAME = "history.json"; private final Context context; private volatile JSONObject history; /** * Listener for when the history is loaded. */ public static interface HistoryListener { public void onFinishedLoading(); public void onFinishedSaving(); } private HistoryListener listener; /** * Creates a history manager. * HistoryListener can be null. */ public HistoryManager(Context context, HistoryListener listener) { this.context = context; this.listener = listener; // While history is loading from disk, we ignore any changes clients might ask for. history = null; load(); } public void setListener(HistoryListener listener) { this.listener = listener; } /** * Gets the json object for a particular game type. */ private JSONObject getGameObject(GameType gameType) throws JSONException { if (history == null) { throw new JSONException("null history"); } JSONObject gameObject = history.optJSONObject(gameType.toString()); if (gameObject == null) { gameObject = new JSONObject(); } return gameObject; } /************************ Setters *****************************/ /** * Set the best place (1st, 2nd, 3rd) for a game type. * NOTE: It's expected for the client to figure out if it is the best place. */ public void setBestPlace(GameType gameType, int place) { try { JSONObject gameObject = getGameObject(gameType); gameObject.put(BEST_PLACE_KEY, place); history.put(gameType.toString(), gameObject); } catch (JSONException e) { Log.e(TAG, "error setting place", e); } } /** * Set the best star count for a game type. * NOTE: It's expected for the client to figure out if it is the best star count. */ public void setBestStarCount(GameType gameType, int count) { try { JSONObject gameObject = getGameObject(gameType); gameObject.put(BEST_STAR_COUNT_KEY, count); history.put(gameType.toString(), gameObject); } catch (JSONException e) { Log.e(TAG, "error setting place", e); } } /** * Set the best time for a game type. * NOTE: it's expected for the client to figure out if it is the best time since some will want * bigger and some will want smaller numbers. */ public void setBestTime(GameType gameType, long timeInMilliseconds) { try { JSONObject gameObject = getGameObject(gameType); gameObject.put(BEST_TIME_MILLISECONDS_KEY, timeInMilliseconds); history.put(gameType.toString(), gameObject); } catch (JSONException e) { Log.e(TAG, "error setting time", e); } } /** * Set the best score for a game type. * NOTE: it's expected for the client to figure out if it is the best score since some will want * bigger and some will want smaller numbers. */ public void setBestScore(GameType gameType, double score) { try { JSONObject gameObject = getGameObject(gameType); gameObject.put(BEST_SCORE_KEY, score); history.put(gameType.toString(), gameObject); } catch (JSONException e) { Log.e(TAG, "error setting score", e); } } /** * Set the best distance for a game type. * NOTE: it's expected for the client to figure out if it is the best distance since some will * want bigger and some will want smaller numbers. */ public void setBestDistance(GameType gameType, double distanceInMeters) { try { JSONObject gameObject = getGameObject(gameType); gameObject.put(BEST_DISTANCE_METERS_KEY, distanceInMeters); history.put(gameType.toString(), gameObject); } catch (JSONException e) { Log.e(TAG, "error setting distance", e); } } /** * Sets an arbitrary jsonObject a game might want. */ public void setArbitraryData(GameType gameType, JSONObject data) { try { JSONObject gameObject = getGameObject(gameType); gameObject.put(ARBITRARY_DATA_KEY, data); history.put(gameType.toString(), gameObject); } catch (JSONException e) { Log.e(TAG, "error setting distance", e); } } /************************ Getters *****************************/ /** * Returns the best place so far. Null if no value has been given yet. */ public Integer getBestPlace(GameType gameType) { try { JSONObject gameObject = getGameObject(gameType); return gameObject.getInt(BEST_PLACE_KEY); } catch (JSONException e) { return null; } } /** * Returns the best star count so far. Null if no value has been given yet. */ public Integer getBestStarCount(GameType gameType) { try { JSONObject gameObject = getGameObject(gameType); return gameObject.getInt(BEST_STAR_COUNT_KEY); } catch (JSONException e) { return null; } } /** * Returns the best time so far. Null if no value has been given yet. */ public Long getBestTime(GameType gameType) { try { JSONObject gameObject = getGameObject(gameType); return gameObject.getLong(BEST_TIME_MILLISECONDS_KEY); } catch (JSONException e) { return null; } } /** * Returns the best score so far. Null if no value has been given yet. */ public Double getBestScore(GameType gameType) { try { JSONObject gameObject = getGameObject(gameType); return gameObject.getDouble(BEST_SCORE_KEY); } catch (JSONException e) { return null; } } /** * Returns the best distance so far. Null if no value has been given yet. */ public Double getBestDistance(GameType gameType) { try { JSONObject gameObject = getGameObject(gameType); return gameObject.getDouble(BEST_DISTANCE_METERS_KEY); } catch (JSONException e) { return null; } } /** * Returns arbitrary JSONObject a game might want. Null if no value has been given yet. */ public JSONObject getArbitraryData(GameType gameType) { try { JSONObject gameObject = getGameObject(gameType); return gameObject.getJSONObject(ARBITRARY_DATA_KEY); } catch (JSONException e) { return null; } } /********************** File Management **************************/ /** * Saves the file in the background. */ public void save() { new AsyncTask<Void, Void, Void>() { @Override protected Void doInBackground(Void... params) { try { FileOutputStream outputStream = context.openFileOutput(FILENAME, Context.MODE_PRIVATE); byte[] bytes = history.toString().getBytes(); outputStream.write(bytes); outputStream.close(); Log.i(TAG, "Saved: " + history); } catch (IOException e) { Log.w(TAG, "Couldn't save JSON at: " + FILENAME); } catch (Exception e) { Log.w(TAG, "Crazy exception happened", e); } return null; } @Override protected void onPostExecute(Void result) { if (listener != null) { listener.onFinishedSaving(); } } }.execute(); } /** * Loads the history object from file. Then merges with any changes that might have occured while * we waited for it to load. */ private void load() { new AsyncTask<Void, Void, Void>() { @Override protected Void doInBackground(Void... params) { try { File file = new File(context.getFilesDir(), FILENAME); int length = (int) file.length(); if (length <= 0) { history = new JSONObject(); return null; } byte[] bytes = new byte[length]; FileInputStream inputStream = new FileInputStream(file); inputStream.read(bytes); inputStream.close(); history = new JSONObject(new String(bytes, "UTF-8")); Log.i(TAG, "Loaded: " + history); } catch (JSONException e) { Log.w(TAG, "Couldn't create JSON for: " + FILENAME); } catch (UnsupportedEncodingException e) { Log.d(TAG, "Couldn't decode: " + FILENAME); } catch (IOException e) { Log.w(TAG, "Couldn't read history: " + FILENAME); } return null; } @Override protected void onPostExecute(Void result) { if (listener != null) { listener.onFinishedLoading(); } } }.execute(); } }