Java tutorial
/* * Copyright (C) 2014 The Android Open Source Project * * 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.murati.oszk.audiobook.model; import android.app.Activity; import android.support.v4.media.MediaMetadataCompat; import com.murati.oszk.audiobook.utils.LogHelper; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.net.URL; import java.net.URLConnection; import java.util.ArrayList; import java.util.Iterator; /** * Utility class to get a list of available tracks based on a server-side JSON * configuration. */ public class RemoteJSONSource extends Activity implements MusicProviderSource { private static final String TAG = LogHelper.makeLogTag(RemoteJSONSource.class); protected static final String CATALOG_URL = "https://s3.amazonaws.com/murati/ekonyvtar_remote.json"; protected static final String JSON_MUSIC = "music"; private static final String JSON_TRACK_TITLE = "title"; private static final String JSON_EBOOK_TITLE = "album"; private static final String JSON_WRITER = "artist"; private static final String JSON_GENRE = "genre"; private static final String JSON_SOURCE = "source"; private static final String JSON_IMAGE = "image"; private static final String JSON_TRACK_NUMBER = "trackNumber"; private static final String JSON_TOTAL_TRACK_COUNT = "totalTrackCount"; private static final String JSON_DURATION = "duration"; @Override public Iterator<MediaMetadataCompat> iterator() { try { int slashPos = CATALOG_URL.lastIndexOf('/'); String path = CATALOG_URL.substring(0, slashPos + 1); JSONObject jsonObj = fetchJSON(CATALOG_URL); ArrayList<MediaMetadataCompat> tracks = new ArrayList<>(); if (jsonObj != null) { JSONArray jsonTracks = jsonObj.getJSONArray(JSON_MUSIC); if (jsonTracks != null) { for (int j = 0; j < jsonTracks.length(); j++) { MediaMetadataCompat media = buildFromJSON(jsonTracks.getJSONObject(j), path); if (media != null) tracks.add(media); } } } return tracks.iterator(); } catch (JSONException e) { LogHelper.e(TAG, e, "Could not retrieve track list"); throw new RuntimeException("Could not retrieve track list", e); } } protected MediaMetadataCompat buildFromJSON(JSONObject json, String basePath) throws JSONException { String writer = json.getString(JSON_WRITER); String ebook = json.getString(JSON_EBOOK_TITLE); String title = json.getString(JSON_TRACK_TITLE); int trackNumber = json.getInt(JSON_TRACK_NUMBER); String genre = json.getString(JSON_GENRE); String source = json.getString(JSON_SOURCE); String iconUrl = json.getString(JSON_IMAGE); int totalTrackCount = json.getInt(JSON_TOTAL_TRACK_COUNT); int duration = json.getInt(JSON_DURATION) * 1000; // ms LogHelper.d(TAG, "Loaded tracks: ", json); // Media is stored relative to JSON file if (!source.startsWith("http")) { source = basePath + source; } if (!iconUrl.startsWith("http")) { iconUrl = basePath + iconUrl; } // Since we don't have a unique ID in the server, we fake one using the hashcode of // the music source. In a real world app, this could come from the server. String id = String.valueOf(source.hashCode()); // Adding the music source to the MediaMetadata (and consequently using it in the // mediaSession.setMetadata) is not a good idea for a real world music app, because // the session metadata can be accessed by notification listeners. This is done in this // sample for convenience only. //noinspection ResourceType // Skip faulty ones if (ebook == null || title == null || ebook.trim().length() * title.trim().length() == 0) { LogHelper.e(TAG, "Error processing JSON: " + json.toString()); return null; } // Fix writer if (writer == null || writer.trim().length() == 0) { if (title.contains(":")) { writer = title.split(":")[0]; } else { writer = "Ismeretlen szerz"; //TODO: resource } } //Fix title TODO: Strip from API ebook = ebook.replace(""", ""); ebook = ebook.replace("\"", ""); title = title.replace(""", "\""); return new MediaMetadataCompat.Builder().putString(MediaMetadataCompat.METADATA_KEY_MEDIA_ID, id) .putString(CUSTOM_METADATA_TRACK_SOURCE, source) .putString(MediaMetadataCompat.METADATA_KEY_ALBUM, ebook) .putString(MediaMetadataCompat.METADATA_KEY_WRITER, writer) .putLong(MediaMetadataCompat.METADATA_KEY_DURATION, duration) .putString(MediaMetadataCompat.METADATA_KEY_GENRE, genre) .putString(MediaMetadataCompat.METADATA_KEY_ALBUM_ART_URI, iconUrl) .putString(MediaMetadataCompat.METADATA_KEY_TITLE, title) .putLong(MediaMetadataCompat.METADATA_KEY_TRACK_NUMBER, trackNumber) .putLong(MediaMetadataCompat.METADATA_KEY_NUM_TRACKS, totalTrackCount).build(); } /** * Download a JSON file from a server, parse the content and return the JSON * object. * * @return result JSONObject containing the parsed representation. */ private JSONObject fetchJSON(String urlString) throws JSONException { BufferedReader reader = null; try { URLConnection urlConnection = new URL(urlString).openConnection(); reader = new BufferedReader(new InputStreamReader(urlConnection.getInputStream(), "utf-8")); StringBuilder sb = new StringBuilder(); String line; while ((line = reader.readLine()) != null) { sb.append(line); } return new JSONObject(sb.toString()); } catch (JSONException e) { throw e; } catch (Exception e) { LogHelper.e(TAG, "Failed to parse the json for media list", e); return null; } finally { if (reader != null) { try { reader.close(); } catch (IOException e) { // ignore } } } } }