Parsing two rows of CSV data in Android?

Question

So I am relatively new to Android and I am trying to parse a web based CSV document and use two of the values from this document in my app. I have already successfully parsed a CSV document but it only had 1 row. The document I am trying to parse looks like this:

Light,2012-08-20T11:04:42.407301Z,107
Temperature,2012-08-20T11:04:42.407301Z,24

I am trying to get the "107" and the "24" values. Can anyone explain how to do this? This is the code for my current CSV parser class which can successfully parse one line of CSV data.

public class CSVParser {
    static InputStream is = null;
    private String value;

    public String getCSV(String url) {
        // Making HTTP request
        try {
            // defaultHttpClient
            DefaultHttpClient httpClient = new DefaultHttpClient();
            HttpGet httpGet = new HttpGet(url);

            HttpResponse httpResponse = httpClient.execute(httpGet);
            HttpEntity httpEntity = httpResponse.getEntity();
            is = httpEntity.getContent();           

        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        BufferedReader reader = new BufferedReader(new InputStreamReader(is));
        try {
            String line;
            while ((line = reader.readLine()) != null) {
                String[] RowData = line.split(",");
                value = RowData[2];
                // do something with "data" and "value"
            }
        } catch (IOException ex) {
            // handle exception
        } finally {
            try {
                is.close();
            } catch (IOException e) {
                // handle exception
            }
        }
        return value;
    }
}

I don't get the question. What you are doing seems correct... you are reading 1 line at a time so it should work. — EsbenG
– EsbenG, Commented Aug 20, 2012 at 11:23

Davos555 · Accepted Answer · 2012-08-20 11:28:27Z

2

I see you are assigning value = rowData[2], which looks like on the 2 row csv you are only returning the 24 as you assign value each time you read a line. Ie first time it's assigned 107, then on the next readLine it is overwritten with 24.

You should make the value variable an array (if you know number of items to get) or list that can hold multiple strings. Then you add to this array or list in each readLine loop.

So first time it would be (if using value as a List<string>)

  while ((line = reader.readLine()) != null) {
    string[] RowData = line.split(",");
    value.add(RowData[2]);
  }

First time round it will add 107 to the list, then next line it will add 24.

answered Aug 20, 2012 at 11:28

Davos555

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12 Comments

IronButterfly Over a year ago

Thanks for the reply! I dont have enough space to fit all the new code so i'll just explain what i've done. First off i changed public String getCSV(String url) to public List <String> getCSV(String url) and i also declared a private List <String> value then i implemented the code you suggested and added a return statement for the list value. But now im facing a problem. I have another class called TempLight which is basically used to display these values from the CSV. In this class i declared a List <String> values then CSVParser CSV = new CSVParser();values = CSV.getCSV(CsvURL);

IronButterfly Over a year ago

Then i did String light = values.get(0); String temp = values.get(1); and then set them as text for two different textviews but when i run the program it just crashes. Do you have any idea why this may be? I have enabled the internet permission in the manifest xml and i have parsed CSV data before..

Davos555 Over a year ago

You'll need to post any error data (ie exceptions text) or otherwise it's just speculation.

IronButterfly Over a year ago

i think it's saying that it's a null pointer exception any idea on how to fix this?

Davos555 Over a year ago

That means that something is not returning an object ie is null. If you are using eclipse is should pause on the exception. It will tell you in the exception code which is the null variable, on which line of code. It will be near the top of the exception text.

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Elemental · Accepted Answer · 2012-08-20 11:24:56Z

1

You have the right idea - so in your idea the while loop run once for each row in the stream until you run out of rows (readline returns null)

Then a single row is split up into multiple strings using split. In your case split should return a array of three (three comma separated elements in the list)

RowData[0] will contain the text descripition (eg Light)
RowData[1] will contain the timestamp
RowData[2] will contain the number you want

If you want a integer you might want to do something like Integer.Parse(RowData[2])

answered Aug 20, 2012 at 11:24

Elemental

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