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/*
* 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.android.music.utils;
import java.util.Arrays;
/**
* Utility class to help on queue related tasks.
*/
public class MediaIDHelper {
private static final String TAG = "MediaIDHelper";
// Media IDs used on browseable items of MediaBrowser
public static final String MEDIA_ID_ROOT = "__ROOT__";
public static final String MEDIA_ID_MUSICS_BY_ARTIST = "__BY_ARTIST__";
public static final String MEDIA_ID_MUSICS_BY_ALBUM = "__BY_ALBUM__";
public static final String MEDIA_ID_MUSICS_BY_SONG = "__BY_SONG__";
public static final String MEDIA_ID_MUSICS_BY_PLAYLIST = "__BY_PLAYLIST__";
public static final String MEDIA_ID_MUSICS_BY_SEARCH = "__BY_SEARCH__";
public static final String MEDIA_ID_NOW_PLAYING = "__NOW_PLAYING__";
private static final char CATEGORY_SEPARATOR = 31;
private static final char LEAF_SEPARATOR = 30;
public static String createMediaID(String musicID, String... categories) {
// MediaIDs are of the form <categoryType>/<categoryValue>|<musicUniqueId>, to make it easy
// to find the category (like genre) that a music was selected from, so we
// can correctly build the playing queue. This is specially useful when
// one music can appear in more than one list, like "by genre -> genre_1"
// and "by artist -> artist_1".
StringBuilder sb = new StringBuilder();
if (categories != null && categories.length > 0) {
sb.append(categories[0]);
for (int i = 1; i < categories.length; i++) {
sb.append(CATEGORY_SEPARATOR).append(categories[i]);
}
}
if (musicID != null) {
sb.append(LEAF_SEPARATOR).append(musicID);
}
return sb.toString();
}
public static String createBrowseCategoryMediaID(String categoryType, String categoryValue) {
return categoryType + CATEGORY_SEPARATOR + categoryValue;
}
/**
* Extracts unique musicID from the mediaID. mediaID is, by this sample's convention, a
* concatenation of category (eg "by_genre"), categoryValue (eg "Classical") and unique
* musicID. This is necessary so we know where the user selected the music from, when the music
* exists in more than one music list, and thus we are able to correctly build the playing
* queue.
*
* @param mediaID that contains the musicID
* @return musicID
*/
public static String extractMusicIDFromMediaID(String mediaID) {
int pos = mediaID.indexOf(LEAF_SEPARATOR);
if (pos >= 0) {
return mediaID.substring(pos + 1);
}
return null;
}
/**
* Extracts category and categoryValue from the mediaID. mediaID is, by this sample's
* convention, a concatenation of category (eg "by_genre"), categoryValue (eg "Classical") and
* mediaID. This is necessary so we know where the user selected the music from, when the music
* exists in more than one music list, and thus we are able to correctly build the playing
* queue.
*
* @param mediaID that contains a category and categoryValue.
*/
public static String[] getHierarchy(String mediaID) {
int pos = mediaID.indexOf(LEAF_SEPARATOR);
if (pos >= 0) {
mediaID = mediaID.substring(0, pos);
}
return mediaID.split(String.valueOf(CATEGORY_SEPARATOR));
}
public static String extractBrowseCategoryValueFromMediaID(String mediaID) {
String[] hierarchy = getHierarchy(mediaID);
if (hierarchy != null && hierarchy.length == 2) {
return hierarchy[1];
}
return null;
}
private static boolean isBrowseable(String mediaID) {
return mediaID.indexOf(LEAF_SEPARATOR) < 0;
}
public static String getParentMediaID(String mediaID) {
String[] hierarchy = getHierarchy(mediaID);
if (!isBrowseable(mediaID)) {
return createMediaID(null, hierarchy);
}
if (hierarchy == null || hierarchy.length <= 1) {
return MEDIA_ID_ROOT;
}
String[] parentHierarchy = Arrays.copyOf(hierarchy, hierarchy.length - 1);
return createMediaID(null, parentHierarchy);
}
}
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