In order to receive notification of user-directed changes to the current history item, implement the HistoryListener interface and attach it via addHistoryListener.
public class HistoryExample implements EntryPoint, HistoryListener {
private Label lbl = new Label();
public void onModuleLoad() {
// Create three hyperlinks that change the application's history.
Hyperlink link0 = new Hyperlink("link to foo", "foo");
Hyperlink link1 = new Hyperlink("link to bar", "bar");
Hyperlink link2 = new Hyperlink("link to baz", "baz");
// If the application starts with no history token, start it off in the
// 'baz' state.
String initToken = History.getToken();
if (initToken.length() == 0)
initToken = "baz";
// onHistoryChanged() is not called when the application first runs. Call
// it now in order to reflect the initial state.
onHistoryChanged(initToken);
// Add widgets to the root panel.
VerticalPanel panel = new VerticalPanel();
panel.add(lbl);
panel.add(link0);
panel.add(link1);
panel.add(link2);
RootPanel.get().add(panel);
// Add history listener
History.addHistoryListener(this);
}
public void onHistoryChanged(String historyToken) {
// This method is called whenever the application's history changes. Set
// the label to reflect the current history token.
lbl.setText("The current history token is: " + historyToken);
}
}
| addHistoryListener(HistoryListener) | Adds a listener to be informed of changes to the browser's history stack. |
| back() | Programmatic equivalent to the user pressing the browser's 'back' button. |
| forward() | Programmatic equivalent to the user pressing the browser's 'forward' button. |
| getToken() | Gets the current history token. |
| newItem(String) | Adds a new browser history entry. |
| onHistoryChanged(String) | |
| removeHistoryListener(HistoryListener) | Removes a history listener. |