BorderLayoutContainer ContentPanel expand does not work if executed from code

[raivis]

Hello. Just noticed, that if I set up BorderLayoutPanel and populate it with ContentPanel, then ContentPanel's collapse and expand will not work if i execute it from my own code (Toolbutton works as expected).
rev 1806

public class GxtModule implements EntryPoint {


    @Override
    public void onModuleLoad() {
        RootPanel rootPanel = RootPanel.get();


        final BorderLayoutContainer blcMain = new BorderLayoutContainer();
        blcMain.setBorders(true);


        final ContentPanel cpCenter = new ContentPanel();
        final ContentPanel cpSouth = new ContentPanel();


        MarginData centerData = new MarginData();


        BorderLayoutData southData = new BorderLayoutData(100);
        southData.setMargins(new Margins(5));
        southData.setCollapsible(true);
        southData.setSplit(true);


        blcMain.setCenterWidget(cpCenter, centerData);
        blcMain.setSouthWidget(cpSouth, southData);


        TextButton btExpander = new TextButton("Colapse/expand");
        btExpander.addDomHandler(new ClickHandler() {


            @Override
            public void onClick(ClickEvent event) {
                cpSouth.setExpanded(!cpSouth.isExpanded());
            }
        }, ClickEvent.getType());


        cpCenter.add(btExpander);


        blcMain.setWidth(500);
        blcMain.setHeight(500);
        rootPanel.add(blcMain);
    }
}

I also noticed, that isExpanded always returns true regardless ContentPanel's state. After running this code ContentPanel is at first collapsed, but when I click the button second time I am getting exception that leads to:

...Caused by: java.lang.NullPointerException: null
    at com.sencha.gxt.widget.core.client.container.BorderLayoutContainer.onCollapse(BorderLayoutContainer.java:599)
    at com.sencha.gxt.widget.core.client.container.BorderLayoutContainer$Handler.onBeforeCollapse(BorderLayoutContainer.java:228)
...

I also tried to use local boolean variable instead of isExpanded(). Exception does not get triggered but ContentPanel still remains collapsed.

[Colin Alworth]

Thanks for the report, there is something wrong there, and we'll look into it.

Here is a workaround that should get you by for now:

  @Override  public void onModuleLoad() {
    RootPanel rootPanel = RootPanel.get();


    final BorderLayoutContainer blcMain = new BorderLayoutContainer();
    blcMain.setBorders(true);


    final ContentPanel cpCenter = new ContentPanel();
    final ContentPanel cpSouth = new ContentPanel();


    MarginData centerData = new MarginData();


    BorderLayoutData southData = new BorderLayoutData(100);
    southData.setMargins(new Margins(5));
    southData.setCollapsible(true);
    southData.setSplit(true);


    blcMain.setCenterWidget(cpCenter, centerData);
    blcMain.setSouthWidget(cpSouth, southData);


    TextButton btExpander = new TextButton("Colapse/expand");
    btExpander.addDomHandler(new ClickHandler() {
      private boolean expanded = true;
      @Override
      public void onClick(ClickEvent event) {
        Widget w = blcMain.getSouthWidget();
        if (w instanceof CollapsePanel) {// collapsed, need to expand
          expand((CollapsePanel) w);
        } else {// w instanceof ContentPanel
          ((ContentPanel) w).collapse();
        }
      }
      private native void expand(CollapsePanel w) /*-{
        w.@com.sencha.gxt.widget.core.client.CollapsePanel::onExpandButton()();
      }-*/;
    }, ClickEvent.getType());


    cpCenter.add(btExpander);


    blcMain.setWidth(500);
    blcMain.setHeight(500);
    rootPanel.add(blcMain);
  }

[raivis]

Thanks for the workaround, it's working this way.

[darrellmeyer]

This is fixed SVN (rev 1953). Change will go out in next release later this week.

[darrellmeyer]

Fixed in beta 1.