How do I specify the sort order for children in an expandable list?

Question

I am working on a conference application in which we want sessions to be grouped by time first and then by room location. I successfully sorted one by one or the other in my ExpandableListActivity, but failed with primary and secondary sorting.

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Tune

• Custom Content Provider (Extends ContentProvider)
• Custom list adapter (extends BaseExpandableListAdapter)
• Custom action list (extends ExpandableListActivity)

Inquiry

Cursor cursor = context.getContentResolver() .query(uri, ScheduleData.PROJECTION, null, null, ScheduleData.SORT_ORDER); 

The sort order

  public static final String SORT_ORDER = TimeSlots.QUALIFIED_TIMESTART + " ASC"; // timeslots.timestart 

Failed to Fulfill Primary & Secondary Sort Orders

  public static final String SORT_ORDER = TimeSlots.QUALIFIED_TIMESTART + " ASC, " + Locations.QUALIFIED_NAME + " ASC"; // timeslots.timestart ASC, locations.name ASC public static final String SORT_ORDER = TimeSlots.QUALIFIED_TIMESTART + ", " + Locations.QUALIFIED_NAME + " ASC"; // timeslots.timestart, locations.name ASC 

The second point does not seem to affect the order. Is this a limitation of ExpandableListActivity? Should I specify multiple sort order items in different ways?

Answer 1

It turns out that there was a comparator in the class that redefined the sort order specified in the ORDERBY . When using the ORDERBY above, without a comparator, I got the required sort. You can do it anyway, but I kill the extra code and select the ORDERBY .

Comparator Path:

 // Sort children Collections.sort(group.children, CHILD_COMPARATOR); // Specify sort by location static final Comparator<Child> CHILD_COMPARATOR = new Comparator<Child>() { @Override public int compare (Child child1, Child child2) { return child1.location.toLowerCase().compareTo(child2.location.toLowerCase()); } }; 

Answer 2

Just enter the data in the "ArrayAdapter", sort it the way you want, and then return the adapter to the list of actions.

Answer 3

This is actually not an answer, but I can not write comments. The string SORT_ORDER must be correct. But you can try using the shell and executing the sql lite query directly so that you can narrow down the problem.

• run emulator with your application
• in your console type:

  adb shell

• Go to the directory of your application; eg:

  cd / data / data / com.myapp / databases)

• run the SQLLite command line tool by typing:

  sqlite3 <filename>

• If you do not know the name of your database file, simply enter "ls" to see all the files in this directory.

• Now you can enter your request. For instance:

SELECT * FROM time intervals, locations ORDER BY timeslots.timestart, locations.name;

link: http://www.sqlite.org/sqlite.html