CODEWITHSUNDEEP
gwtpanelchildren
Jogi
Jogi

Reputation: 25

SimplePanel can only contain one child widget

When i run the following Code and push Button "Push", more than once a time, i get browser error "simplePanel can only contain one child widget". How can i solve that problem? thank you in advance! Jogi

public class Projekt implements EntryPoint {

    private RootPanel rootPanel;

    public void onModuleLoad() {

        rootPanel = RootPanel.get("gwtContainer");
        rootPanel.setSize("1902", "868");

         final AbsolutePanel boundaryPanel = new AbsolutePanel();
         boundaryPanel.setStyleName("frame1");
         boundaryPanel.setSize("1455px", "600px");       

         final Diagram diagram = new Diagram(boundaryPanel);

         RootPanel.get().add(boundaryPanel, 446, 242);


         final Connector con = new Connector(100, 300, 300, 500);

         Button la = new Button("Push");
         la.setSize("200", "200");
         RootPanel.get().add(la);

         Button la2 = new Button("Push2");
         la2.setSize("200", "200");
         RootPanel.get().add(la2);

         final Image img = new Image("images/concrete.svg");
         img.setSize("200", "200");


         final Shape shapei = new Shape(img);


         Image img2 = new Image("images/variable.svg");
         img2.setSize("200", "200");
         boundaryPanel.add(img2, 200,200);

         final Shape shapei2 = new Shape(img2);
         shapei2.showOnDiagram(diagram);

         la.addClickHandler(new ClickHandler(){

            @Override
            public void onClick(ClickEvent event) {
                 boundaryPanel.add(img, 100,100);
                 shapei.showOnDiagram(diagram);
            }

         });
         la2.addClickHandler(new ClickHandler(){

                @Override
                public void onClick(ClickEvent event) {

                     con.showOnDiagram(diagram);
                }

             });


         diagram.addDiagramListener(new DiagramListenerAdapter() {

              @Override
              public void onElementConnect(ElementConnectEvent event) {
                if (con.startEndPoint.isGluedToConnectionPoint()) {
                    Widget connected = con.startEndPoint.gluedConnectionPoint.parentWidget;
                    if(connected.equals(shapei.connectedWidget)){
                  Image logo = new Image("images/xor.svg");
                  logo.setSize("100", "100");
                  boundaryPanel.add(logo);
                }
                    else if(connected.equals(shapei2.connectedWidget)){
                         Image logo2 = new Image("images/and.svg");
                      logo2.setSize("100", "100");
                      boundaryPanel.add(logo2);
                    };
              }}
            });

}}

Upvotes: 0

Views: 545

Answers (2)

Andrei Volgin
Andrei Volgin

Reputation: 41089

RootPanel.get() is a SimplePanel. You try to add more than one child to it, resulting in this error.

Instead, you should add HTMLPanel, for example, to your RootPanel, and then add all the children to this HTMLPanel.

Upvotes: 1

Lista
Lista

Reputation: 2246

I suppose your Diagram extends GWT's SimplePanel class? SimplePanel can contain only a single widget, have a look here:

http://www.gwtproject.org/javadoc/latest/com/google/gwt/user/client/ui/SimplePanel.html

You could either extend a different class, or call the remove(Widget w) method to remove the existing widget before trying to add a new one.

Upvotes: 0

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