Skip to content

Instantly share code, notes, and snippets.

@kzim44
Created May 11, 2014 04:23
Show Gist options
  • Save kzim44/a4e16a2034c4f723de8d to your computer and use it in GitHub Desktop.
Save kzim44/a4e16a2034c4f723de8d to your computer and use it in GitHub Desktop.
A custom cursor loader to facilitate using a SQLite database with the Android LoaderManager framework, but without the need for a Content Provider.
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
*/
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;
}
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment