com.aizak.drawnote.model.loader.SimpleCursorLoader.java Source code

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Here is the source code for com.aizak.drawnote.model.loader.SimpleCursorLoader.java

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/*
 * Copyright 2012 CodeSlap - Cristian Castiblanco
 * 
 * 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.aizak.drawnote.model.loader;

import android.content.Context;
import android.database.Cursor;
import android.support.v4.content.AsyncTaskLoader;

/**
 * Used to write apps that run on platforms prior to Android 3.0. When running
 * on Android 3.0 or above, this implementation is still used; it does not try
 * to switch to the framework's implementation. See the framework SDK
 * documentation for a class overview.
 * 
 * This was based on the CursorLoader class
 * 
 * @author cristian
 */
public abstract class SimpleCursorLoader extends AsyncTaskLoader<Cursor> {
   private Cursor mCursor;

   public SimpleCursorLoader(Context context) {
      super(context);
   }

   /* Runs on a worker thread */
   @Override
   public abstract Cursor loadInBackground();

   /* Runs on the UI thread */
   @Override
   public void deliverResult(Cursor cursor) {
      if (isReset()) {
         // An async query came in while the loader is stopped
         if (cursor != null) {
            cursor.close();
         }
         return;
      }
      Cursor oldCursor = mCursor;
      mCursor = cursor;

      if (isStarted()) {
         super.deliverResult(cursor);
      }

      if ((oldCursor != null) && (oldCursor != cursor) && !oldCursor.isClosed()) {
         oldCursor.close();
      }
   }

   /**
    * Starts an asynchronous load of the contacts list data. When the result is
    * ready the callbacks will be called on the UI thread. If a previous load
    * has been completed and is still valid the result may be passed to the
    * callbacks immediately.
    * <p/>
    * Must be called from the UI thread
    */
   @Override
   protected void onStartLoading() {
      if (mCursor != null) {
         deliverResult(mCursor);
      }
      if (takeContentChanged() || (mCursor == null)) {
         forceLoad();
      }
   }

   /**
    * Must be called from the UI thread
    */
   @Override
   protected void onStopLoading() {
      // Attempt to cancel the current load task if possible.
      cancelLoad();
   }

   @Override
   public void onCanceled(Cursor cursor) {
      if ((cursor != null) && !cursor.isClosed()) {
         cursor.close();
      }
   }

   @Override
   protected void onReset() {
      super.onReset();

      // Ensure the loader is stopped
      onStopLoading();

      if ((mCursor != null) && !mCursor.isClosed()) {
         mCursor.close();
      }
      mCursor = null;
   }
}