I'm trying to populate a ListView in my activity using a ContentProvider that I created, but when the onLoadFinished() method is called, it receives a null Cursor. (The CursorLoader is not null though).
I'm trying to debug the ContentProvider, but the debugger doesn't stop on the query() method (it stops when the URI doesn't match, when I fix that, it doesn't stop!!!). So without debug I'm having a hard time to find out why my cursor returns as null on the onLoadFinished() method.
Here is the code for the activity:
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.LoaderManager;
import android.support.v4.content.CursorLoader;
import android.support.v4.content.Loader;
import android.support.v4.widget.SimpleCursorAdapter;
import android.view.Menu;
import android.widget.ListView;
public class PicturesListActivity extends FragmentActivity
implements LoaderManager.LoaderCallbacks<Cursor> {
SimpleCursorAdapter myAdapter;
String[] projection = {"_id", "name"};
String[] from = {"name"};
String orderBy = "year DESC";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_pictures_list);
final ListView listview = (ListView) findViewById(R.id.lv_pictures_list);
// The TextView in simple_list_item_1
int[] toViews = {android.R.id.text1};
// Prepare the loader. Either re-connect with an existing one, or start a new one.
getSupportLoaderManager().initLoader(0, null, this);
myAdapter = new SimpleCursorAdapter(this, android.R.layout.simple_list_item_1, null, from, toViews, 0);
listview.setAdapter(myAdapter);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.pictures_list, menu);
return true;
}
@Override
// Called when a new Loader needs to be created (initLoader)
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
Uri uri = Uri.parse(DatabaseContentProvider.AUTHORITY + DatabaseContentProvider.TABLE_PATH_PICTURE);
CursorLoader cl = new CursorLoader(this, uri, projection, null, null, orderBy);
return cl;
}
@Override
// Called automatically when a previously created loader has finished loading
public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
myAdapter.swapCursor(data);
}
@Override
// Called when a previously created loader is reset, making the data unavailable
public void onLoaderReset(Loader<Cursor> loader) {
myAdapter.swapCursor(null);
}
}
And here is the ContentProvider that I created:
import android.content.ContentProvider;
import android.content.ContentValues;
import android.content.UriMatcher;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteQueryBuilder;
import android.net.Uri;
import android.text.TextUtils;
public class DatabaseContentProvider extends ContentProvider {
//database
private DatabaseAssetHelper dbhelper;
//stuff
public static final String AUTHORITY = "com.frlnrl.myapp.DatabaseContentProvider";
public static final String TABLE_PATH_PICTURE = DatabaseContract.Pictures.TABLE_PICTURE;
public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY);
//UriMatcher
private static final UriMatcher sURIMatcher = new UriMatcher(UriMatcher.NO_MATCH);
static {
sURIMatcher.addURI(AUTHORITY, TABLE_PATH_PICTURE , 37);
}
@Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
// TODO Auto-generated method stub
int numberOfLinesDeleted = 0;
return numberOfLinesDeleted;
}
@Override
public String getType(Uri uri) {
return null;
}
@Override
public Uri insert(Uri uri, ContentValues values) {
// TODO Auto-generated method stub
return null;
}
@Override
public boolean onCreate() {
dbhelper = new DatabaseAssetHelper(getContext());
return true;
}
@Override
public Cursor query(Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder) {
SQLiteQueryBuilder queryBuilder = new SQLiteQueryBuilder();
SQLiteDatabase db = dbhelper.getReadableDatabase();
int uriReceived = sURIMatcher.match(uri);
switch (uriReceived) {
case 37:
if (TextUtils.isEmpty(sortOrder)) sortOrder = "_ID ASC";
queryBuilder.setTables(DatabaseContract.Pictures.TABLE_PICTURE);
break;
default:
throw new IllegalArgumentException("Unknown oh eu aqui URI");
}
Cursor cursor = queryBuilder.query(db, projection, selection, selectionArgs, null, null, sortOrder);
cursor.setNotificationUri(getContext().getContentResolver(), uri);
return cursor;
}
@Override
public int update(Uri uri, ContentValues values, String selection,
String[] selectionArgs) {
// TODO Auto-generated method stub
int numberOfLineUpdated = 0;
return numberOfLineUpdated;
}
}
Does anyone got any idea why is returns a empty cursor?
