1 files changed, 129 insertions, 0 deletions
diff --git a/MusicDemo/src/main/java/com/example/android/musicservicedemo/utils/QueueHelper.java b/MusicDemo/src/main/java/com/example/android/musicservicedemo/utils/QueueHelper.java
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+++ b/MusicDemo/src/main/java/com/example/android/musicservicedemo/utils/QueueHelper.java
@@ -0,0 +1,129 @@
+/*
+ * Copyright (C) 2014 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.example.android.musicservicedemo.utils;
+
+import android.media.MediaMetadata;
+import android.media.session.MediaSession;
+
+import com.example.android.musicservicedemo.model.MusicProvider;
+
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+
+import static com.example.android.musicservicedemo.utils.MediaIDHelper.MEDIA_ID_MUSICS_BY_GENRE;
+
+/**
+ * Utility class to help on queue related tasks.
+ */
+public class QueueHelper {
+
+    private static final String TAG = "QueueHelper";
+
+    public static final List<MediaSession.QueueItem> getPlayingQueue(String mediaId,
+            MusicProvider musicProvider) {
+
+        // extract the category and unique music ID from the media ID:
+        String[] category = MediaIDHelper.extractBrowseCategoryFromMediaID(mediaId);
+
+        // This sample only supports genre category.
+        if (!category[0].equals(MEDIA_ID_MUSICS_BY_GENRE) || category.length != 2) {
+            LogHelper.e(TAG, "Could not build a playing queue for this mediaId: ", mediaId);
+            return null;
+        }
+
+        String categoryValue = category[1];
+        LogHelper.e(TAG, "Creating playing queue for musics of genre ", categoryValue);
+
+        List<MediaSession.QueueItem> queue = convertToQueue(
+                musicProvider.getMusicsByGenre(categoryValue));
+
+        return queue;
+    }
+
+    public static final List<MediaSession.QueueItem> getPlayingQueueFromSearch(String query,
+            MusicProvider musicProvider) {
+
+        LogHelper.e(TAG, "Creating playing queue for musics from search ", query);
+
+        return convertToQueue(musicProvider.searchMusics(query));
+    }
+
+
+    public static final int getMusicIndexOnQueue(Iterable<MediaSession.QueueItem> queue,
+             String mediaId) {
+        int index = 0;
+        for (MediaSession.QueueItem item: queue) {
+            if (mediaId.equals(item.getDescription().getMediaId())) {
+                return index;
+            }
+            index++;
+        }
+        return -1;
+    }
+
+    public static final int getMusicIndexOnQueue(Iterable<MediaSession.QueueItem> queue,
+             long queueId) {
+        int index = 0;
+        for (MediaSession.QueueItem item: queue) {
+            if (queueId == item.getQueueId()) {
+                return index;
+            }
+            index++;
+        }
+        return -1;
+    }
+
+    private static final List<MediaSession.QueueItem> convertToQueue(
+            Iterable<MediaMetadata> tracks) {
+        List<MediaSession.QueueItem> queue = new ArrayList<>();
+        int count = 0;
+        for (MediaMetadata track : tracks) {
+            // 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.
+            MediaSession.QueueItem item = new MediaSession.QueueItem(
+                    track.getDescription(), count++);
+            queue.add(item);
+        }
+        return queue;
+
+    }
+
+    /**
+     * Create a random queue. For simplicity sake, instead of a random queue, we create a
+     * queue using the first genre,
+     *
+     * @param musicProvider
+     * @return
+     */
+    public static final List<MediaSession.QueueItem> getRandomQueue(MusicProvider musicProvider) {
+        Iterator<String> genres = musicProvider.getGenres().iterator();
+        if (!genres.hasNext()) {
+            return new ArrayList<>();
+        }
+        String genre = genres.next();
+        Iterable<MediaMetadata> tracks = musicProvider.getMusicsByGenre(genre);
+
+        return convertToQueue(tracks);
+    }
+
+
+
+    public static final boolean isIndexPlayable(int index, List<MediaSession.QueueItem> queue) {
+        return (queue != null && index >= 0 && index < queue.size());
+    }
+}
+\ No newline at end of file