StaleDataException: access closed cursor
- by Aurora
In my application, after enough clicking around, I get this error:
06-08 19:47:59.967: ERROR/AndroidRuntime(2429): java.lang.RuntimeException: Unable to pause activity {com.MYAPP.app/com.MYAPP.app.MainActivity}: android.database.StaleDataException: Access closed cursor
What I have is a Tab Activity (my MainActivity), which has a ListActivity as the contents for each tab. Inside the onCreate for each ListActivity I get a cursor that represents the data to be displayed in that list.
The onListItemClick for each list also creates another activity, so clicking on an item in the list will show more information about that item in a new screen. It's inconsistent, but after enough clicking into these new activities, or going back to the ListView from a new activity, the program crashes.
In searching around for a solution to my problem, I did stumble upon registerDataSetObserver, but it doesn't seem to be the whole answer. I am also having trouble finding documentation on it, so I'm not sure I fully understand it. I have a custom ListAdapter that both my ListViews use and have called registerDataSetObservers on the cursors there.
I have attached the relevant code from one of my ListActivities and from my custom ListAdapter class.
The ListActivity. I have two of these, almost identical, except they both have different cursors created from different database queries:
import com.MYAPP.app.listmanager.DeviceListAdapter;
public class AllSensorsActivity extends ListActivity{
private DeviceListAdapter AllList;
private DbManager db;
protected Cursor AllCur;
protected Cursor AllSensors;
private static final String TAG = "AllSensorsActivity";
@Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
Log.e(TAG, "Calling All onCreate");
db = new DbManager(this);
db.open();
AllCur = db.fetchAllDevices();
startManagingCursor(AllCur);
AllSensors = db.fetchAllSensors();
startManagingCursor(AllSensors);
AllList = new DeviceListAdapter(this, AllCur, AllSensors);
setListAdapter(AllList);
}
@Override
protected void onListItemClick(ListView l, View v, int position, long id){
String device_name = (String) ((DeviceListAdapter)getListAdapter()).getItem(position);
String sensor_string = ((DeviceListAdapter)getListAdapter()).getSensors(id);
Intent i = new Intent(this, SensorActivity.class);
Bundle bundle = new Bundle();
bundle.putString("NAME", device_name);
i.putExtras(bundle);
bundle.putString("SENSORS", sensor_string);
i.putExtras(bundle);
this.startActivity(i);
}
The custom ListAdapter:
public class DeviceListAdapter extends BaseAdapter {
private static final String TAG = "DeviceListAdapter";
private Context mContext;
private Cursor mSensors;
private Cursor mDevices;
protected MyDataSetObserver sensors_observer;
protected MyDataSetObserver devices_observer;
public DeviceListAdapter(Context context, Cursor devices, Cursor sensors){
mContext = context;
mDevices = devices;
mSensors = sensors;
sensors_observer = new MyDataSetObserver();
mSensors.registerDataSetObserver(sensors_observer);
devices_observer = new MyDataSetObserver();
mDevices.registerDataSetObserver(devices_observer);
}
// ... more functions and stuff that are not relevant go down here...
}
private class MyDataSetObserver extends DataSetObserver {
public void onChanged(){
Log.e(TAG, "CHANGED CURSOR!");
}
public void onInvalidated(){
Log.e(TAG, "INVALIDATED CURSOR!");
}
}
Should I just have MyDataSetObserver catch the exception and move on? I'd like a more robust solution than that if possible. Or is there some other way I could rearrange my program so that the staleDataException doesn't occur (as often)? I believe that it is happening because I am launching the new activity in my onListItemClick.
