显示ProgressDialog Android

Question

我有一个EditText，它从用户和一个searchButton中获取一个字符串。单击searchButton时，它将搜索XML文件并将其显示在ListView中。

我能够从用户那里获取输入，搜索XML文件并在ListView中也显示usersearched值。

我想要的是ProgressDialog在单击searchButton之后显示一个“请等待...正在检索数据...”之类的信息，然后在显示数据时将其关闭。

public class Tab1Activity extends ListActivity {

private Button okButton;

private Button searchButton;

Toast toast;

String xml;

private TextView searchText;

private String searchTextString;

HashMap<String, String> o;

ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>();

@Override

public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.tab1);

    searchButton = (Button) findViewById(R.id.search_button);

    searchButton.setOnClickListener(new View.OnClickListener() {

        public void onClick(View v) {

            // TODO Auto-generated method stub

            System.out.print("hello");

            searchText = (TextView) findViewById(R.id.search_text);

            searchTextString = searchText.getText().toString();

            readXml(searchTextString);

        }

    });

}

private void readXml(String searchTextString1) {

    ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>();

    String xml = XMLfunctions.getXML();

            //Here XMLfunctions is class name which parse xml

    Document doc = XMLfunctions.XMLfromString(xml);

    int numResults = XMLfunctions.numResults(doc);

    if ((numResults <= 0)) {

        Toast.makeText(Tab1Activity.this, "Testing xmlparser",

                Toast.LENGTH_LONG).show();

        finish();

    }

    NodeList nodes = doc.getElementsByTagName("result");

    for (int i = 0; i < nodes.getLength(); i++) {

        HashMap<String, String> map = new HashMap<String, String>();

        Element e = (Element) nodes.item(i);

        String nameMapString = XMLfunctions.getValue(e, "name");