When to close cursor in Android?

I have an app that uses a cursor to select data via rawQuery from an SQLite DB to populate a ListView in Android. Every time the user clicks on a listview item I create a new instance of Activity t开发者_StackOverflowo re-populate listview.

Is it better to call cursor.close() and db.close() to avoid memory problems? I actually have db.close() in OnDestroy() of my activity.

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You can close the cursor once you have retrieved the values for that particular object inside your method.

btw...You don't have to recreate a listview every time for a user click event. Just notify that there is some change in data of your adapter that has been set on the listview.

Something like

youradaptername.notifyDataSetChanged();

This should repopulate contents inside ur listview automatically.

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Well if you are creating a new instance every time of the same Activity (though I am not sure its a good programming practice). You can close the cursor as soon as your have finished traversing / iterating through the source of the listview.

Example:

A sample implementation would be something like

//Pre cursor code
startManagingCursor(cursor);
if (cursor.moveToFirst()) {
    do {
        if (cursor.getString(0).equals(value)) {
            cursor.close();
            a = true;
            return a;
        }
    } while (cursor.moveToNext());
}

//Close cursor here, when its work is complete
cursor.close();

//Post cursor code ...