Hi,
I was looking through the sample gwt code provided with gwt, and in hacking around with it - i had two questions re. things that we'nt particularly clear to me (code posted below - slightly long: sorry)
1) The popup dialog box doesnt seem to be set to be 'hidden' at first, and even though its been assembled, it doesnt actually show up until the button is clicked - why is this? (i dont, for example see any dialogBox.Hide() call
2) in creating a similar dialogbox, basically through copying the code, i'm facing the problem that between calls to the dialogbox - the contents persist, so if i hide the box with the button on the dialog box, the next time it is called - the new contents are just appended above it... what am i doing wrong?
many thanks!
public void onModuleLoad() {
final Button sendButton = new Button("Send");
final TextBox nameField = new TextBox();
nameField.setText("GWT User");
final Label errorLabel = new Label();
// We can add style names to widgets
sendButton.addStyleName("sendButton");
// 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);
RootPanel.get("errorLabelContainer").add(errorLabel);
// 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);
}
});
// Create a handler for the sendButton and nameField
class MyHandler implements ClickHandler, KeyUpHandler {
/**
* Fired when the user clicks on the sendButton.
*/
public void onClick(ClickEvent event) {
sendNameToServer();
}
/**
* Fired when the user types in the nameField.
*/
public void onKeyUp(KeyUpEvent event) {
if (event.getNativeKeyCode() == KeyCodes.KEY_ENTER) {
sendNameToServer();
}
}
/**
* Send the name from the nameField to the server and wait for a response.
*/
private void sendNameToServer() {
// First, we validate the input.
errorLabel.setText("");
String textToServer = nameField.getText();
if (!FieldVerifier.isValidName(textToServer)) {
errorLabel.setText("Please enter at least four characters");
return;
}
// Then, we send the input to the server.
sendButton.setEnabled(false);
textToServerLabel.setText(textToServer);
serverResponseLabel.setText("");
greetingService.greetServer(textToServer,
new AsyncCallback<String>() {
public void onFailure(Throwable caught) {
// Show the RPC error message to the user
dialogBox
.setText("Remote Procedure Call - Failure");
serverResponseLabel
.addStyleName("serverResponseLabelError");
serverResponseLabel.setHTML(SERVER_ERROR);
dialogBox.center();
closeButton.setFocus(true);
}
public void onSuccess(String result) {
dialogBox.setText("Remote Procedure Call");
serverResponseLabel
.removeStyleName("serverResponseLabelError");
serverResponseLabel.setHTML(result);
dialogBox.center();
closeButton.setFocus(true);
}
});
}
}
// Add a handler to send the name to the server
MyHandler handler = new MyHandler();
sendButton.addClickHandler(handler);
nameField.addKeyUpHandler(handler);
}