OpenTracks/src/main/java/com/google/android/apps/mytracks/DeleteAsyncTask.java

package com.google.android.apps.mytracks;

/*
 * Copyright 2013 Google Inc.
 *
 * 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.
 */

import android.content.Context;
import android.os.AsyncTask;

import com.google.android.apps.mytracks.content.MyTracksProviderUtils;

/**
 * Async Task to delete tracks.
 * 
 * @author Jimmy Shih
 */
public class DeleteAsyncTask extends AsyncTask<Void, Integer, Boolean> {

  private DeleteActivity deleteActivity;
  private final long[] trackIds;
  private final Context context;

  // true if the AsyncTask has completed
  private boolean completed;

  /**
   * Creates an AsyncTask.
   * 
   * @param deleteActivity the activity currently associated with this task
   * @param trackIds the track ids to delete. To delete all, set to size 1 with
   *          trackIds[0] == -1L
   */
  public DeleteAsyncTask(DeleteActivity deleteActivity, long[] trackIds) {
    this.deleteActivity = deleteActivity;
    this.trackIds = trackIds;
    context = deleteActivity.getApplicationContext();
    completed = false;
  }

  /**
   * Sets the current activity associated with this AyncTask.
   * 
   * @param deleteActivity the current activity, can be null
   */
  public void setActivity(DeleteActivity deleteActivity) {
    this.deleteActivity = deleteActivity;
    if (completed && deleteActivity != null) {
      deleteActivity.onAsyncTaskCompleted();
    }
  }

  @Override
  protected void onPreExecute() {
    if (deleteActivity != null) {
      deleteActivity.showProgressDialog();
    }
  }

  @Override
  protected Boolean doInBackground(Void... params) {
    MyTracksProviderUtils myTracksProviderUtils = MyTracksProviderUtils.Factory.get(context);

    if (trackIds.length == 1 && trackIds[0] == -1L) {
      myTracksProviderUtils.deleteAllTracks(context);
    } else {
      for (long id : trackIds) {
        if (isCancelled()) {
          return false;
        }
        myTracksProviderUtils.deleteTrack(context, id);
      }
    }
    return true;
  }

  @Override
  protected void onPostExecute(Boolean result) {
    completed = true;
    if (deleteActivity != null) {
      deleteActivity.onAsyncTaskCompleted();
    }
  }
}