Java – how do I set the message when I get an exception

public class XMLParser {

public class XMLParser {

    // constructor
    public XMLParser() {

    }


    public String getXmlFromUrl(String url) {
        String responseBody = null;

        getset d1 = new getset();
        String d = d1.getData(); // text
        String y = d1.getYear(); // year
        String c = d1.getCircular();
        String p = d1.getPage();

        List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
        nameValuePairs.add(new BasicNameValuePair("YearID",y));

        nameValuePairs.add(new BasicNameValuePair("CircularNo",c));

        nameValuePairs.add(new BasicNameValuePair("SearchText",d));
        nameValuePairs.add(new BasicNameValuePair("pagenumber",p));
        try {

            HttpClient httpclient = new DefaultHttpClient();
            HttpPost httppost = new HttpPost(url);
            httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
            HttpResponse response = httpclient.execute(httppost);

            httpentity entity = response.getEntity();

            responseBody = EntityUtils.toString(entity);

        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        // return XML
        return responseBody;
    }


    public Document getDomElement(String xml) {
        Document doc = null;
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        try {

            DocumentBuilder db = dbf.newDocumentBuilder();

            InputSource is = new InputSource();
            is.setCharacterStream(new StringReader(xml));
            doc = db.parse(is);

        } catch (ParserConfigurationException e) {
            Log.e("Error: ",e.getMessage());
            return null;
        } catch (SAXException e) {
            Log.e("Error: ",e.getMessage());

            // i m getting Exception here

            return null;
        } catch (IOException e) {
            Log.e("Error: ",e.getMessage());
            return null;
        }

        return doc;
    }

    /**
     * Getting node value
     * 
     * @param elem
     *            element
     */
    public final String getElementValue(Node elem) {
        Node child;
        if (elem != null) {
            if (elem.hasChildNodes()) {
                for (child = elem.getFirstChild(); child != null; child = child
                        .getNextSibling()) {
                    if (child.getNodeType() == Node.TEXT_NODE) {
                        return child.getNodeValue();
                    }
                }
            }
        }
        return "";
    }

    /**
     * Getting node value
     * 
     * @param Element
     *            node
     * @param key
     *            string
     * */
    public String getValue(Element item,String str) {
        NodeList n = item.getElementsByTagName(str);
        return this.getElementValue(n.item(0));
    }
}

I get an exception in this class to parse the data I want to print this message in another class extended from activity Can you tell me how it is? I tried a lot, but I couldn't do it

public class AndroidXMLParsingActivity extends Activity {

    public int currentPage = 1;
    public ListView lisView1;
    static final String KEY_ITEM = "docdetails";
    static final String KEY_NAME = "heading";
    public Button btnNext;
    public Button btnPre;
    public static String url = "http://dev.taxmann.com/TaxmannService/TaxmannService.asmx/GetNotificationList";

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        // listView1
        lisView1 = (ListView) findViewById(R.id.listView1);

        // Next
        btnNext = (Button) findViewById(R.id.btnNext);
        // Perform action on click
        btnNext.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                currentPage = currentPage + 1;
                ShowData();
            }
        });

        // PrevIoUs
        btnPre = (Button) findViewById(R.id.btnPre);
        // Perform action on click
        btnPre.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                currentPage = currentPage - 1;
                ShowData();
            }
        });

        ShowData();
    }

    public void ShowData() {
        XMLParser parser = new XMLParser();
        String xml = parser.getXmlFromUrl(url); // getting XML

        Document doc = parser.getDomElement(xml); // getting DOM element

        NodeList nl = doc.getElementsByTagName(KEY_ITEM);

        int displayPerPage = 5; // Per Page
        int TotalRows = nl.getLength();
        int indexRowStart = ((displayPerPage * currentPage) - displayPerPage);
        int TotalPage = 0;
        if (TotalRows <= displayPerPage) {
            TotalPage = 1;
        } else if ((TotalRows % displayPerPage) == 0) {
            TotalPage = (TotalRows / displayPerPage);
        } else {
            TotalPage = (TotalRows / displayPerPage) + 1; // 7
            TotalPage = (int) TotalPage; // 7
        }
        int indexRowEnd = displayPerPage * currentPage; // 5
        if (indexRowEnd > TotalRows) {
            indexRowEnd = TotalRows;
        }

        // Disabled Button Next
        if (currentPage >= TotalPage) {
            btnNext.setEnabled(false);
        } else {
            btnNext.setEnabled(true);
        }

        // Disabled Button Previos
        if (currentPage <= 1) {
            btnPre.setEnabled(false);
        } else {
            btnPre.setEnabled(true);
        }

        // Load Data from Index
        int RowID = 1;
        ArrayList<HashMap<String,String>> menuItems = new ArrayList<HashMap<String,String>>();
        HashMap<String,String> map;

        // RowID
        if (currentPage > 1) {
            RowID = (displayPerPage * (currentPage - 1)) + 1;
        }

        for (int i = indexRowStart; i < indexRowEnd; i++) {
            Element e = (Element) nl.item(i);
            // adding each child node to HashMap key => value
            map = new HashMap<String,String>();
            map.put("RowID",String.valueOf(RowID));
            map.put(KEY_NAME,parser.getValue(e,KEY_NAME));

            // adding HashList to ArrayList
            menuItems.add(map);

            RowID = RowID + 1;

        }

        SimpleAdapter sAdap;
        sAdap = new SimpleAdapter(AndroidXMLParsingActivity.this,menuItems,R.layout.list_item,new String[] { "RowID",KEY_NAME },new int[] { R.id.ColRowID,R.id.ColName });
        lisView1.setAdapter(sAdap);
    }

}

This is the course where I want to print this message

Solution

You can simply surround your code with try / catch blocks as follows:

String xml;
Document doc;
NodeList nl;

try {

    xml = parser.getXmlFromUrl(url); // getting XML
    doc = parser.getDomElement(xml); // getting DOM element
    nl = doc.getElementsByTagName(KEY_ITEM);
} catch (Exception e) {
    Toast.makeText(getApplicationContext(),e.toString(),Toast.LENGTH_LONG).show();
}

In this way, you don't have to make any changes in the xmlparser class, and you can easily handle any exceptions that occur when parsing code in the main class itself In addition, toast is the best thing I think in order to display error messages

I hope it helps thank you.