Question

My app lets user select a category and then input other info based on the category. Say they pick category ‘Electronics’ then they can input CD, PS3, iPod etc in it. I have several categories like Hobbies, General, Home etc.

I would like to display the items in a listview sorted by category like this:

Electronics
 -CD
 -PS3
 -iPod
Books
 -Perl
 -Android is fun
 -C

etc etc…

I am fetching all the data from the db using:

return mDb.query(DATABASE_TABLE, new String[] {KEY_ROWID,KEY_CATEGORY
                KEY_NAME, KEY_STATUS, KEY_DESCRIPTION}, null, null, null, null, null);

i also tried using the rawQuery and using the DISTINCT tag but that’s not going to work, since it will pick unique items. I am using a simpleCursorAdapter to display the data:

SimpleCursorAdapter list =
    new SimpleCursorAdapter(this, R.layout.items, c, mapFrom, mapTo);
setListAdapter(list);

Answer 1

I guessing that you want this:

return mDb.query(DATABASE_TABLE, 
            new String[] {KEY_ROWID, KEY_CATEGORY, KEY_NAME, KEY_STATUS, KEY_DESCRIPTION}, 
            null, null, null, null, 
            KEY_CATEGORY + ", " + KEY_NAME);

Using the Order By parameter your query is first ordered by category then name. This would give you a result like:

Category, Name
--------------
Books, Android is fun
Books, C
Books, Perl
Electronics, CD
Electronics, iPod
Electronics, PS3

If you only wanted to list Books, then you simply use:

return mDb.query(DATABASE_TABLE, 
            new String[] {KEY_ROWID, KEY_CATEGORY, KEY_NAME, KEY_STATUS, KEY_DESCRIPTION}, 
            KEY_CATEGORY + "=?", 
            new String[] {"Books"}, 
            null, null, 
            KEY_NAME);

Of course, if you only want to display the category and name in a ListView then you it will be more efficient to shorten you SELECT clause to only what you need: new String[] {KEY_ROWID, KEY_CATEGORY, KEY_NAME}.

Addition from comments

In order to get a result like this:

Books
    Android is fun
    C
    Perl
Electronics
    CD
    iPod
    PS3

You can either use an ExpandableListView or process the Cursor yourself into a List<String> and pass this to a ArrayAdapter.