Question

In my database I have 2 tables. For a table I want to display only the items which has a certain id in the second column. I have an adapter for all the items from the table but I don’t know how should it look like for viewing only the items I need. Any idea is welcome.

Here is my adapter :

private void populate(){
        c=prod.fetchAll();
        startManagingCursor(c);

        adapter=new SimpleCursorAdapter(this,R.layout.listproduct,c,
                new String[] {ProductDbAdapter.KEY_ITEM,ProductDbAdapter.KEY_QUANTITY,ProductDbAdapter.KEY_UNITS},
                new int[] {R.id.prod1,R.id.prod2,R.id.prod3});

       lv.setAdapter(adapter);

    }

The code for ProductDbAdapter is :

public class ProductDbAdapter extends AbstractDbAdapter {

    public static final String KEY_LISTID = "list_id";
    public static final String KEY_ITEM = "item";
    public static final String KEY_QUANTITY="quantity";
    public static final String KEY_UNITS="units";

    public static final String KEY_ROWID = "_id";

    private static final String DATABASE_TABLE = "products";


    public ProductDbAdapter(Context ctx) {
        super(ctx);
    }


    public long create(Integer listid, String item,String quantity,String units) {
        ContentValues args = new ContentValues();
        args.put(KEY_LISTID,listid);
        args.put(KEY_ITEM,item);
        args.put(KEY_QUANTITY,quantity);
        args.put(KEY_UNITS,units);

        return mDb.insert(DATABASE_TABLE, null,args);
    }


    public boolean updateproduct(long rowId,Integer listid, String item,String quantity,String units) {
        ContentValues values = new ContentValues();
        values.put(KEY_LISTID, listid);
        values.put(KEY_ITEM, item);
        values.put(KEY_QUANTITY, quantity);
        values.put(KEY_UNITS,units);
        return mDb.update(DATABASE_TABLE, values, KEY_ROWID + "="+ rowId, null) > 0;
    }

    public boolean delete(long rowId) {
        return mDb.delete(DATABASE_TABLE, KEY_ROWID + "=" + rowId, null) > 0;
    }


    public Cursor fetchAll() {
        return mDb.query(DATABASE_TABLE, new String[] {KEY_ROWID, KEY_LISTID,KEY_ITEM,KEY_QUANTITY,
                KEY_UNITS}, null, null, null, null, null);
    }


    public Cursor fetch(long rowId) throws SQLException {
        Cursor mCursor =
            mDb.query(true, DATABASE_TABLE, new String[] {KEY_ROWID,
                    KEY_LISTID,KEY_ITEM,KEY_QUANTITY, KEY_UNITS}, KEY_ROWID + "=" + rowId, null,
                    null, null, null, null);
        if (mCursor != null) {
            mCursor.moveToFirst();
        }
        return mCursor;

    }
}

What I am trying to do is to display only the items with a certain list_id..

Answer 1

Why do you request a cursor which returns all item when you only want items with a certain id? Change your database query so you only get the items with the ids you define in the where-statement of your database query.

Let the database so the job of filtering the correct items for you, it’s not the job of an adapter.