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POHow to manipulate cursor's data before displaying it in a ListView (using a Loader)?
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  1. POHow to manipulate cursor's data before displaying it in a ListView (using a Loader)?
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    copied!<p>Each item of my <code>SherlockListFragment</code> contains 3 <code>TextView</code>s : a name and two numbers. The data comes from the table <code>objective</code> of my database, which has the following structure : </p> <pre><code>CREATE TABLE objective ( _id INTEGER PRIMARY KEY, id_project INTEGER NOT NULL, activity_code INTEGER NOT NULL, day_duration INTEGER NOT NULL, week_frequency INTEGER NOT NULL, FOREIGN KEY(id_project) REFERENCES project(id_project) ); </code></pre> <p>Moreover, I have read that populating a list from a cursor should be done by using a loader (particularly when using a database because it can be a very slow operation). I have found a <code>SimpleCursorLoader</code> class <a href="https://stackoverflow.com/a/7422343/615882">here on stackoverflow</a>, but it maps data to a field directly.</p> <p>That is not really what I want, because as you can see, in my <code>objective</code> table I have an <code>activity_code</code>. So I would like to replace it by a string (I have an Enum that lists all of my activity codes and returns, for each one, a string resource identifier).</p> <p>Do you know how I could manipulate data before it is displayed in the <code>TextView</code>s ?</p> <p>Here is my <code>SherlockListFragment</code></p> <pre><code>public class ObjectivesDisplayFragment extends SherlockListFragment implements LoaderManager.LoaderCallbacks&lt;Cursor&gt; { private Activity activity; private SimpleCursorAdapter adapter; @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { return inflater.inflate(R.layout.objectives_display, container, false); } @Override public void onActivityCreated(Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); activity = getActivity(); String[] columns = new String[] { "activity_code", "day_duration", "week_frequency" }; int[] to = new int[] { R.id.activityName, R.id.objectiveDuration, R.id.objectiveFrequency }; getLoaderManager().initLoader(0x01, null, this); adapter = new SimpleCursorAdapter(activity.getApplicationContext(), R.layout.objective_row, null, columns, to, SimpleCursorAdapter.FLAG_REGISTER_CONTENT_OBSERVER); setListAdapter(adapter); } public Loader&lt;Cursor&gt; onCreateLoader(int arg0, Bundle arg1) { return new SimpleCursorLoader(activity) { @Override public Cursor loadInBackground() { DatabaseHelper dbHelper = DatabaseHelper.getInstance(activity); String query = "SELECT _id, activity_code, day_duration, week_frequency FROM objective WHERE id_project = ?"; String[] args = new String[] { "1" }; // projectId Cursor results = dbHelper.getReadableDatabase().rawQuery(query, args); return results; } }; } public void onLoadFinished(Loader&lt;Cursor&gt; arg0, Cursor cursor) { adapter.swapCursor(cursor); } public void onLoaderReset(Loader&lt;Cursor&gt; arg0) { adapter.swapCursor(null); } } </code></pre> <p>EDIT : I do not need to close the cursor and the database in SimpleCursorLoader > loadInBackground, right ? Otherwise the data could not be read. So is the closing operation automatically handled or do I need to do it myself elsewhere?</p>
 

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