Getting Started with Google App Engine for Java - Beginning Java Google App Engine - page 36

// Add the nameField and sendButton to the RootPanel

// Use RootPanel.get() to get the entire body element

RootPanel.get("nameFieldContainer").add(nameField);

RootPanel.get("sendButtonContainer").add(sendButton);

// Focus the cursor on the name field when the app loads

nameField.setFocus(true);

nameField.selectAll();

// Create the popup dialog box

final DialogBox dialogBox = new DialogBox();

dialogBox.setText("Remote Procedure Call");

dialogBox.setAnimationEnabled(true);

final Button closeButton = new Button("Close");

// We can set the id of a widget by accessing its Element

closeButton.getElement().setId("closeButton");

final Label textToServerLabel = new Label();

final HTML serverResponseLabel = new HTML();

VerticalPanel dialogVPanel = new VerticalPanel();

dialogVPanel.addStyleName("dialogVPanel");

dialogVPanel.add(new HTML("<b>Sending name to the server:</b>"));

dialogVPanel.add(textToServerLabel);

dialogVPanel.add(new HTML("<br><b>Server replies:</b>"));

dialogVPanel.add(serverResponseLabel);

dialogVPanel.setHorizontalAlignment(VerticalPanel.ALIGN_RIGHT);

dialogVPanel.add(closeButton);

dialogBox.setWidget(dialogVPanel);

// Add a handler to close the DialogBox

closeButton.addClickHandler(new ClickHandler() {

public void onClick(ClickEvent event) {

dialogBox.hide();

sendButton.setEnabled(true);

sendButton.setFocus(true);

}

});

Without ever even using GWT you can quickly browse the code and follow exactly
what is happening. The method loads the Google Web Toolkit elements in an order
and fashion that lays out your page perfectly. Take the following lines, for example.