从eventHandler中显示GWT对话框

Question

I am trying to display a GWT DialogBox when I capture an exception by an event handler. The DialogBox does not display. I've confirmed the event handler is called because

Window.alert("some msg") 

does display. The DialogBox does display when I create it outside the event handler in a View object. I assume the DialogBox does not have access to the current display. Is there a way to get this displayed?

Here is a code snippet:

eventBus.addHandler(ProcessingExceptionEvent.TYPE, new ProcessingExceptionEventHandler() {
    public void onProcessingException(ProcessingExceptionEvent event) {
        // Window.alert("some msg");
        final WiseAlertPanel errorAlert = new WiseAlertPanel("ERROR MESSAGE: " + event.getMessage());
        errorAlert.autoPositionAndShow();
    }
});

public class WiseAlertPanel extends DialogBox {
    VerticalPanel vpPopupl = new VerticalPanel();

    public WiseAlertPanel(String text) {
        setGlassEnabled(true);
        Button button = new Button("Close");
        button.addClickHandler(new ClickHandler() {
            public void onClick(ClickEvent event) {
                WiseAlertPanel.this.hide();
            }
        });

        HorizontalPanel hPanel = new HorizontalPanel();
        hPanel.setHorizontalAlignment(HasHorizontalAlignment.ALIGN_RIGHT);
        hPanel.add(button);

        TextArea label = new TextArea();
        label.setText(text);
        label.setReadOnly(true);
        label.setVisibleLines(5);

        vpPopupl.add(label);
        vpPopupl.add(hPanel);
        setWidget(vpPopupl);
    }

    public void autoPositionAndShow() {
        setPopupPositionAndShow(new PopupPanel.PositionCallback() {
            public void setPosition(int offsetWidth, int offsetHeight) {
                int left = (Window.getClientWidth() - offsetWidth) / 3;
                int top = (Window.getClientHeight() - offsetHeight) / 3;
                WiseAlertPanel.this.setPopupPosition(left, top);
            }
        });
    }

Answer 1

Looks like you have just create the DialogBox "WiseAlertPanel errorAlert" in memory.

Try call the show method in "autoPositionAndShow" like below

public void autoPositionAndShow() {
    setPopupPositionAndShow(new PopupPanel.PositionCallback() {
        public void setPosition(int offsetWidth, int offsetHeight) {
            int left = (Window.getClientWidth() - offsetWidth) / 3;
            int top = (Window.getClientHeight() - offsetHeight) / 3;
            WiseAlertPanel.this.setPopupPosition(left, top);
            show();
        }
    });
}

Reference GWT DialogBox show()