HISTORY MANAGEMENT code

[Nandini Yeltiwar]

import com.google.gwt.core.client.EntryPoint;

import com.google.gwt.event.logical.shared.SelectionEvent;

import com.google.gwt.event.logical.shared.SelectionHandler;

import com.google.gwt.event.logical.shared.ValueChangeEvent;

import com.google.gwt.event.logical.shared.ValueChangeHandler;

import com.google.gwt.user.client.History;

import com.google.gwt.user.client.ui.HTML;

import com.google.gwt.user.client.ui.RootPanel;

import com.google.gwt.user.client.ui.TabPanel;

/**

 * Entry point classes define <code>onModuleLoad()</code>.

 */

public class historyGwt implements EntryPoint {

  TabPanel tabPanel;

  /**

   * This is the entry point method.

   */

  public void onModuleLoad() {

    tabPanel = new TabPanel();

    tabPanel.add(new HTML("<h1> A</h1>"), " Page 0 ");

    tabPanel.add(new HTML("<h1> B</h1>"), " Page 1 ");

    tabPanel.add(new HTML("<h1>C</h1>"), " Page 2 ");

    tabPanel.addSelectionHandler(new SelectionHandler<Integer>(){

      public void onSelection(SelectionEvent<Integer> event) {

        History.newItem("page" + event.getSelectedItem());

      }});

    History.addValueChangeHandler(new ValueChangeHandler<String>() {

      public void onValueChange(ValueChangeEvent<String> event) {

        String historyToken = event.getValue();

        // Parse the history token

        try {

          if (historyToken.substring(0, 4).equals("page")) {

            String tabIndexToken = historyToken.substring(4, 5);

            int tabIndex = Integer.parseInt(tabIndexToken);

            // Select the specified tab panel

            tabPanel.selectTab(tabIndex);

          } else {

            tabPanel.selectTab(0);

          }

        } catch (IndexOutOfBoundsException e) {

          tabPanel.selectTab(0);

        }

      }

    });

    tabPanel.selectTab(0);

    RootPanel.get().add(tabPanel);

  }

}