[FNR] NPE appears after container is removed and then added into DOM in GXT 2.1.1

[christin]

Hi GXT team and community,

we faced with a NPE problem when we try to add a field into form that belong to container in a special state.
The container is removed from DOM and then added back.

Exception occurs in both web mode and compiled modes and we mostly use Firefox and Chrome.

java.lang.NullPointerException: null
    at com.extjs.gxt.ui.client.widget.layout.FormLayout.renderField(FormLayout.java:338)
    at com.extjs.gxt.ui.client.widget.layout.FormLayout.renderComponent(FormLayout.java:307)
    at com.extjs.gxt.ui.client.widget.Layout.renderAll(Layout.java:353)
    at com.extjs.gxt.ui.client.widget.Layout.onLayout(Layout.java:318)
    at com.extjs.gxt.ui.client.widget.layout.AnchorLayout.onLayout(AnchorLayout.java:99)
    at com.extjs.gxt.ui.client.widget.layout.FormLayout.onLayout(FormLayout.java:267)
    at com.extjs.gxt.ui.client.widget.Layout.layout(Layout.java:114)
    at com.extjs.gxt.ui.client.widget.Container.doLayout(Container.java:351)
    at com.extjs.gxt.ui.client.widget.Container.layout(Container.java:444)
    at com.extjs.gxt.ui.client.widget.LayoutContainer.layout(LayoutContainer.java:245)
    at com.extjs.gxt.ui.client.widget.Container.layout(Container.java:427)
    at com.extjs.gxt.ui.client.widget.LayoutContainer.layout(LayoutContainer.java:240)
    at com.example.client.Test$1.componentSelected(Test.java:33)
    at com.example.client.Test$1.componentSelected(Test.java:1)
    at com.extjs.gxt.ui.client.event.SelectionListener.handleEvent(SelectionListener.java:20)
    at com.extjs.gxt.ui.client.event.SelectionListener.handleEvent(SelectionListener.java:1)
    at com.extjs.gxt.ui.client.event.BaseObservable.callListener(BaseObservable.java:178)
    at com.extjs.gxt.ui.client.event.BaseObservable.fireEvent(BaseObservable.java:86)
    at com.extjs.gxt.ui.client.widget.Component.fireEvent(Component.java:462)
    at com.extjs.gxt.ui.client.widget.button.Button.onClick(Button.java:577)
    at com.extjs.gxt.ui.client.widget.button.Button.onComponentEvent(Button.java:285)
    at com.extjs.gxt.ui.client.widget.Component.onBrowserEvent(Component.java:876)
    at com.extjs.gxt.ui.client.widget.form.AdapterField.onBrowserEvent(AdapterField.java:88)
    at com.google.gwt.user.client.DOM.dispatchEventImpl(DOM.java:1307)
    at com.google.gwt.user.client.DOM.dispatchEvent(DOM.java:1263)

Simple code to reproduce the problem

public class Test implements EntryPoint {
    public void onModuleLoad() {
        final TabPanel tabs = new TabPanel();
        final TabItem item = new TabItem("Item 1");
        item.setLayout(new FitLayout());
        final TabItem item2 = new TabItem("Item 2");
        final FormData layoutData = new FormData("-20");
        
        final LayoutContainer container = new LayoutContainer(new FormLayout());
        container.add(new TextField<String>(),layoutData);
        container.add(new AdapterField(new Button("Click",new SelectionListener<ButtonEvent>() {
            @Override
            public void componentSelected(ButtonEvent ce) {
                tabs.removeAll();
                tabs.add(item2);
                tabs.add(item);
                
                container.add(new TextField<String>(),layoutData);
                container.layout();
            }
        })),layoutData);
        item.add(container);
        
        tabs.add(item);
        tabs.add(item2);
        
        RootPanel.get().add(tabs);
    }
}

At the moment we cannot find a workaround so any help is highly appreciated.

Thanks,
Slava V

[sven]

I run the code against the latest SVN version and it works as expected. Marking this as closed. So this is probably already fixed

[sven]

Please also note that you are calling layout on a container while it is not visible. you should never do that.

[christin]

Sven,

thanks for the quick reply. we found a solution by deferring call to layout.

Best regards,
Slava V