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.example.lzhang.stockchartt.media.utils; import android.content.Context; import android.os.Bundle; import android.support.v4.app.FragmentActivity; import android.support.v4.media.MediaMetadataCompat; import android.support.v4.media.session.MediaControllerCompat; import android.support.v4.media.session.MediaSessionCompat; import android.text.TextUtils; import com.example.lzhang.stockchartt.media.VoiceSearchParams; import com.example.lzhang.stockchartt.media.model.MusicProvider; import java.util.ArrayList; import java.util.List; import static com.example.lzhang.stockchartt.media.utils.MediaIDHelper.MEDIA_ID_MUSICS_BY_SEARCH; /** * Utility class to help on queue related tasks. */ public class QueueHelper { private static final String TAG = LogHelper.makeLogTag(QueueHelper.class); private static final int RANDOM_QUEUE_SIZE = 10; public static List<MediaSessionCompat.QueueItem> getPlayingQueue(String mediaId, MusicProvider musicProvider) { // // extract the browsing hierarchy from the media ID: // String[] hierarchy = MediaIDHelper.getHierarchy(mediaId); // // if (hierarchy.length != 2) { // LogHelper.e(TAG, "Could not build a playing queue for this mediaId: ", mediaId); // return null; // } // // String categoryType = hierarchy[0]; // String categoryValue = hierarchy[1]; // LogHelper.d(TAG, "Creating playing queue for ", categoryType, ", ", categoryValue); // // Iterable<MediaMetadataCompat> tracks = null; // // This sample only supports genre and by_search category types. // if (categoryType.equals(MEDIA_ID_MUSICS_BY_GENRE)) { // tracks = musicProvider.getMusicsByGenre(categoryValue); // } else if (categoryType.equals(MEDIA_ID_MUSICS_BY_SEARCH)) { // tracks = musicProvider.searchMusicBySongTitle(categoryValue); // } // if (tracks == null) { // LogHelper.e(TAG, "Unrecognized category type: ", categoryType, " for media ", mediaId); // return null; // } return convertToQueue(MusicProviderV2.getInstance().mMusicListById.values()); } public static List<MediaSessionCompat.QueueItem> getPlayingQueueFromSearch(String query, Bundle queryParams, MusicProvider musicProvider) { LogHelper.d(TAG, "Creating playing queue for musics from search: ", query, " params=", queryParams); VoiceSearchParams params = new VoiceSearchParams(query, queryParams); LogHelper.d(TAG, "VoiceSearchParams: ", params); if (params.isAny) { // If isAny is true, we will play anything. This is app-dependent, and can be, // for example, favorite playlists, "I'm feeling lucky", most recent, etc. return getRandomQueue(musicProvider); } Iterable<MediaMetadataCompat> result = null; if (params.isAlbumFocus) { result = musicProvider.searchMusicByAlbum(params.album); } else if (params.isGenreFocus) { result = musicProvider.getMusicsByGenre(params.genre); } else if (params.isArtistFocus) { result = musicProvider.searchMusicByArtist(params.artist); } else if (params.isSongFocus) { result = musicProvider.searchMusicBySongTitle(params.song); } // If there was no results using media focus parameter, we do an unstructured query. // This is useful when the user is searching for something that looks like an artist // to Google, for example, but is not. For example, a user searching for Madonna on // a PodCast application wouldn't get results if we only looked at the // Artist (podcast author). Then, we can instead do an unstructured search. if (params.isUnstructured || result == null || !result.iterator().hasNext()) { // To keep it simple for this example, we do unstructured searches on the // song title only. A real world application could search on other fields as well. result = musicProvider.searchMusicBySongTitle(query); } return convertToQueue(result, MEDIA_ID_MUSICS_BY_SEARCH, query); } public static int getMusicIndexOnQueue(Iterable<MediaSessionCompat.QueueItem> queue, String mediaId) { int index = 0; for (MediaSessionCompat.QueueItem item : queue) { if (mediaId.equals(item.getDescription().getMediaId())) { return index; } index++; } return -1; } public static int getMusicIndexOnQueue(Iterable<MediaSessionCompat.QueueItem> queue, long queueId) { int index = 0; for (MediaSessionCompat.QueueItem item : queue) { if (queueId == item.getQueueId()) { return index; } index++; } return -1; } private static List<MediaSessionCompat.QueueItem> convertToQueue(Iterable<MediaMetadataCompat> tracks, String... categories) { List<MediaSessionCompat.QueueItem> queue = new ArrayList<>(); int count = 0; for (MediaMetadataCompat track : tracks) { // We create a hierarchy-aware mediaID, so we know what the queue is about by looking // at the QueueItem media IDs. // String hierarchyAwareMediaID = MediaIDHelper.createMediaID( // track.getDescription().getMediaId(), categories); MediaMetadataCompat trackCopy = new MediaMetadataCompat.Builder(track) // .putString(MediaMetadataCompat.METADATA_KEY_MEDIA_ID, hierarchyAwareMediaID) .build(); // We don't expect queues to change after created, so we use the item index as the // queueId. Any other number unique in the queue would work. MediaSessionCompat.QueueItem item = new MediaSessionCompat.QueueItem(trackCopy.getDescription(), count++); queue.add(item); } return queue; } /** * Create a random queue with at most {@link #RANDOM_QUEUE_SIZE} elements. * * @param musicProvider the provider used for fetching music. * @return list containing {@link MediaSessionCompat.QueueItem}'s */ public static List<MediaSessionCompat.QueueItem> getRandomQueue(MusicProvider musicProvider) { List<MediaMetadataCompat> result = new ArrayList<>(RANDOM_QUEUE_SIZE); Iterable<MediaMetadataCompat> shuffled = musicProvider.getShuffledMusic(); for (MediaMetadataCompat metadata : shuffled) { if (result.size() == RANDOM_QUEUE_SIZE) { break; } result.add(metadata); } LogHelper.d(TAG, "getRandomQueue: result.size=", result.size()); return convertToQueue(result, MEDIA_ID_MUSICS_BY_SEARCH, "random"); } public static boolean isIndexPlayable(int index, List<MediaSessionCompat.QueueItem> queue) { return (queue != null && index >= 0 && index < queue.size()); } /** * Determine if two queues contain identical media id's in order. * * @param list1 containing {@link MediaSessionCompat.QueueItem}'s * @param list2 containing {@link MediaSessionCompat.QueueItem}'s * @return boolean indicating whether the queue's match */ public static boolean equals(List<MediaSessionCompat.QueueItem> list1, List<MediaSessionCompat.QueueItem> list2) { if (list1 == list2) { return true; } if (list1 == null || list2 == null) { return false; } if (list1.size() != list2.size()) { return false; } for (int i = 0; i < list1.size(); i++) { if (list1.get(i).getQueueId() != list2.get(i).getQueueId()) { return false; } if (!TextUtils.equals(list1.get(i).getDescription().getMediaId(), list2.get(i).getDescription().getMediaId())) { return false; } } return true; } /** * Determine if queue item matches the currently playing queue item * * @param context for retrieving the {@link MediaControllerCompat} * @param queueItem to compare to currently playing {@link MediaSessionCompat.QueueItem} * @return boolean indicating whether queue item matches currently playing queue item */ public static boolean isQueueItemPlaying(Context context, MediaSessionCompat.QueueItem queueItem) { // Queue item is considered to be playing or paused based on both the controller's // current media id and the controller's active queue item id MediaControllerCompat controller = ((FragmentActivity) context).getSupportMediaController(); if (controller != null && controller.getPlaybackState() != null) { long currentPlayingQueueId = controller.getPlaybackState().getActiveQueueItemId(); String currentPlayingMediaId = controller.getMetadata().getDescription().getMediaId(); String itemMusicId = MediaIDHelper.extractMusicIDFromMediaID(queueItem.getDescription().getMediaId()); if (queueItem.getQueueId() == currentPlayingQueueId && currentPlayingMediaId != null && TextUtils.equals(currentPlayingMediaId, itemMusicId)) { return true; } } return false; } }