Android Open Source - AerisAndroidLibrary Simple Cursor Loader

From Project

Back to project page AerisAndroidLibrary.

License

The source code is released under:

Apache License

If you think the Android project AerisAndroidLibrary listed in this page is inappropriate, such as containing malicious code/tools or violating the copyright, please email info at java2s dot com, thanks.

Java Source Code

package com.example.db;
// w  w w  . j  av  a 2s . co m
import android.content.AsyncTaskLoader;
import android.content.Context;
import android.database.Cursor;

/**
 * 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
 */
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;
  }
}

Java Source Code List