Android Open Source - vanilindy Playlist Adapter

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License

The source code is released under:

Apache License

Java Source Code

/*
 * Copyright (C) 2011 Christopher Eby <kreed@kreed.org>
 *//www . j a v  a2  s .c o m
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

package ch.blinkenlights.android.vanilla;

import android.content.ContentResolver;
import android.content.ContentUris;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.graphics.drawable.Drawable;
import android.net.Uri;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.provider.MediaStore;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.CursorAdapter;
import android.widget.TextView;

/**
 * CursorAdapter backed by MediaStore playlists.
 */
public class PlaylistAdapter extends CursorAdapter implements Handler.Callback, DragListView.DragAdapter {
  private static final String[] PROJECTION = new String[] {
    MediaStore.Audio.Playlists.Members._ID,
    MediaStore.Audio.Playlists.Members.TITLE,
    MediaStore.Audio.Playlists.Members.ARTIST,
    MediaStore.Audio.Playlists.Members.AUDIO_ID,
    MediaStore.Audio.Playlists.Members.PLAY_ORDER,
  };

  private final Context mContext;
  private final Handler mWorkerHandler;
  private final Handler mUiHandler;
  private final LayoutInflater mInflater;
  private final Drawable mExpander;

  private long mPlaylistId;

  private boolean mEditable;

  /**
   * Create a playlist adapter.
   *
   * @param context A context to use.
   * @param worker A looper running a worker thread (to run queries on).
   */
  public PlaylistAdapter(Context context, Looper worker)
  {
    super(context, null, false);

    mContext = context;
    mUiHandler = new Handler(this);
    mWorkerHandler = new Handler(worker, this);
    mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    mExpander = context.getResources().getDrawable(R.drawable.grabber);
  }

  /**
   * Set the id of the backing playlist.
   *
   * @param id The MediaStore id of a playlist.
   */
  public void setPlaylistId(long id)
  {
    mPlaylistId = id;
    mWorkerHandler.sendEmptyMessage(MSG_RUN_QUERY);
  }

  /**
   * Enabled or disable edit mode. Edit mode adds a drag grabber to the left
   * side a views and a delete button to the right side of views.
   *
   * @param editable True to enable edit mode.
   */
  public void setEditable(boolean editable)
  {
    mEditable = editable;
    notifyDataSetInvalidated();
  }

  /**
   * Update the values in the given view.
   */
  @Override
  public void bindView(View view, Context context, Cursor cursor)
  {
    TextView textView = (TextView)view;
    textView.setText(cursor.getString(1));
    textView.setCompoundDrawablesWithIntrinsicBounds(mEditable ? mExpander : null, null, null, null);
    textView.setTag(cursor.getLong(3));
  }

  /**
   * Generate a new view.
   */
  @Override
  public View newView(Context context, Cursor cursor, ViewGroup parent)
  {
    return mInflater.inflate(R.layout.playlist_row, null);
  }

  /**
   * Re-run the query. Should be run on worker thread.
   */
  public static final int MSG_RUN_QUERY = 1;
  /**
   * Update the cursor. Must be run on UI thread.
   */
  public static final int MSG_UPDATE_CURSOR = 2;

  @Override
  public boolean handleMessage(Message message)
  {
    switch (message.what) {
    case MSG_RUN_QUERY: {
      Cursor cursor = runQuery(mContext.getContentResolver());
      mUiHandler.sendMessage(mUiHandler.obtainMessage(MSG_UPDATE_CURSOR, cursor));
      break;
    }
    case MSG_UPDATE_CURSOR:
      changeCursor((Cursor)message.obj);
      break;
    default:
      return false;
    }

    return true;
  }

  /**
   * Query the playlist songs.
   *
   * @param resolver A ContentResolver to query with.
   * @return The resulting cursor.
   */
  private Cursor runQuery(ContentResolver resolver)
  {
    QueryTask query = MediaUtils.buildPlaylistQuery(mPlaylistId, PROJECTION, null);
    return query.runQuery(resolver);
  }

  @Override
  public void move(int from, int to)
  {
    if (from == to)
      // easy mode
      return;

    int count = getCount();
    if (to >= count || from >= count)
      // this can happen when the adapter changes during the drag
      return;

    // The Android API contains a method to move a playlist item, however,
    // it has only been available since Froyo and doesn't seem to work
    // after a song has been removed from the playlist (I think?).

    ContentResolver resolver = mContext.getContentResolver();
    Uri uri = MediaStore.Audio.Playlists.Members.getContentUri("external", mPlaylistId);
    Cursor cursor = getCursor();

    int start = Math.min(from, to);
    int end = Math.max(from, to);

    long order;
    if (start == 0) {
      order = 0;
    } else {
      cursor.moveToPosition(start - 1);
      order = cursor.getLong(4) + 1;
    }

    cursor.moveToPosition(end);
    long endOrder = cursor.getLong(4);

    // clear the rows we are replacing
    String[] args = new String[] { Long.toString(order), Long.toString(endOrder) };
    resolver.delete(uri, "play_order >= ? AND play_order <= ?", args);

    // create the new rows
    ContentValues[] values = new ContentValues[end - start + 1];
    for (int i = start, j = 0; i <= end; ++i, ++j, ++order) {
      cursor.moveToPosition(i == to ? from : i > to ? i - 1 : i + 1);
      ContentValues value = new ContentValues(2);
      value.put(MediaStore.Audio.Playlists.Members.PLAY_ORDER, Long.valueOf(order));
      value.put(MediaStore.Audio.Playlists.Members.AUDIO_ID, cursor.getLong(3));
      values[j] = value;
    }

    // insert the new rows
    resolver.bulkInsert(uri, values);

    changeCursor(runQuery(resolver));
  }

  @Override
  public void remove(int position)
  {
    ContentResolver resolver = mContext.getContentResolver();
    Uri uri = MediaStore.Audio.Playlists.Members.getContentUri("external", mPlaylistId);
    resolver.delete(ContentUris.withAppendedId(uri, getItemId(position)), null, null);
    changeCursor(runQuery(resolver));
  }
}

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