Using simple_list_item_2 with an ArrayAdapter (Android)

Today I wanted to display static a ListView of properties and their values. It’s Friday, so I really wanted to do this with as little work as possible. Android’s free layout simple_list_item_2 sounded like what I wanted, but it wasn’t immediately clear how to handle this. There are a lot of lazy ways we can list single values, but Googling around how to use simple_list_item_2 resulted in lots of questions with no real answer.

I found Mark Assad, who parsed the system layout files into raw XML. The led to the magic answer of TwoLineListItem widget. Finding this widget allowed me to write a simple ArrayAdapter of key/value pairs.

adapter = new ArrayAdapter(this,android.R.layout.simple_list_item_2,list){
        @Override
        public View getView(int position, View convertView, ViewGroup parent){
            TwoLineListItem row;
            if(convertView == null){
                LayoutInflater inflater = (LayoutInflater)getApplicationContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                row = (TwoLineListItem)inflater.inflate(android.R.layout.simple_list_item_2, null);
            }else{
                row = (TwoLineListItem)convertView;
            }
            BasicNameValuePair data = list.get(position);
            row.getText1().setText(data.getName());
            row.getText2().setText(data.getValue());

            return row;
        }
    };
listView.setAdapter(adapter);

Hope this saves someone else some time, as I spent an embarrassing amount of time determined to use the simple_list_item_2 layout.

Enterprise Library Sometimes Chops XML into 2033 Characters

This morning I began what I thought would be an uneventful task in .NET: connect to one database, download as XML some rows from a table that have changed since a given time, then pass that XML to a stored procedure in another database so that the changes can be merged. Just two tables: one relatively small, the other just a 2-column relationship table for the first table. Here’s a contrived snippet to serve the same purpose:

The SQL:

CREATE PROCEDURE dbo.GetXmlValue

AS

SELECT TOP 100
*
FROM sys.all_columns
FOR XML AUTO, ROOT('Root')

The Code:

Database db = GetDatabase();

DataSet set;

using (DbCommand cmd = db.GetStoredProcCommand("dbo.GetXmlValue"))
{
set = db.ExecuteDataSet(cmd);
}

In my application, it was this second table that tripped me a bit. The first only had a few changed rows, so the XML was only 500-1000 characters. The second table generated a much longer XML string – 3864 characters long. My initial plan was to return two tables, each 1 column and 1 row. When using Database.ExecuteDataSet to fetch the results, however, the second table yielded two rows. I backtracked, second guessed myself, and even grabbed a couple of guys in the hall to double check my code. No one could explain it. It seemed odd that this hasn’t come up before for someone here. I did a bit of Googling and only found a couple of results. This Microsoft Knowledgebase Article just says it’s “by design” and to use SQLCommand.ExecuteXmlReader.

The next question that came up was “Well, what does it do if I return a long XML value among other values in the same row?” I tested this out and everything worked as expected. All of the XML was in a single column value as it should be.

I still can’t exactly explain it. ExecuteScalar has a character limit of 2033 characters. I suspect that because each table in my result set is just a single column value, something somewhere is relying on ExecuteScalar.

My solution? In my stored procedure I just stored each of my table results as an XML typed variable, then returned the two together in the same row.