ListEditorWrapper NPE - gwt

Question

GWT 2.5.0
A simple case using ListEditor failed below, what did i miss?
public class OneBean {
private String name;
public OneBean() {
}
public OneBean(String name) {
this.name = name;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
#Override
public String toString() {
return "OneBean [name=" + name + "]";
}
}
public class OneListEditor extends Composite implements
IsEditor<ListEditor<OneBean, OneEditor>> {
interface OneListUiBinder extends UiBinder<Widget, OneListEditor> {}
OneListUiBinder uiBinder = GWT.create(OneListUiBinder.class);
#UiField
VerticalPanel panel;
public OneListEditor() {
initWidget(uiBinder.createAndBindUi(this));
}
#Override
public ListEditor<OneBean, OneEditor> asEditor() {
return listEditor;
}
private ListEditor<OneBean, OneEditor> listEditor = ListEditor
.of(new EditorSource<OneEditor>() {
#Override
public OneEditor create(int index) {
OneEditor widget = new OneEditor();
panel.insert(widget, index);
return widget;
}
});
}
public class OneEditor extends Composite implements Editor<OneBean> {
interface OneUiBinder extends UiBinder<Widget, OneEditor> {}
OneUiBinder uiBinder = GWT.create(OneUiBinder.class);
#UiField
TextBox name;
public OneEditor() {
initWidget(uiBinder.createAndBindUi(this));
}
}
public class OneListEditorApp implements EntryPoint {
#Override
public void onModuleLoad() {
List<OneBean> beans = new ArrayList<OneBean>();
beans.add(new OneBean("1st bean"));
beans.add(new OneBean("2nd bean"));
OneListEditor oneListEditor = new OneListEditor();
oneListEditor.asEditor().setValue(beans); // exception thrown here!
RootPanel.get().add(oneListEditor);
}
}
java.lang.NullPointerException: null
at com.google.gwt.editor.client.adapters.ListEditorWrapper.attach(ListEditorWrapper.java:95)
at com.google.gwt.editor.client.adapters.ListEditor.setValue(ListEditor.java:164)
at OneListEditorApp.onModuleLoad ....
void attach() {
editors.addAll(editorSource.create(workingCopy.size(), 0));
for (int i = 0, j = workingCopy.size(); i < j; i++) {
chain.attach(workingCopy.get(i), editors.get(i)); // ListEditorWrapper NPE here!
}
}
#EDIT
According to the answer from #Thomas Broyer, NPE is gone after EditDriver being wired to OneListEditor below,
interface OneEditorDriver extends
SimpleBeanEditorDriver<OneBean, OneEditor> {}
OneEditorDriver driver = GWT.create(OneEditorDriver.class);
#Override
public ListEditor<OneBean, OneEditor> asEditor() {
listEditor.setEditorChain(new EditorChain<OneBean, OneEditor>() {
#Override
public OneBean getValue(OneEditor subEditor) {
return null;
}
#Override
public void detach(OneEditor subEditor) {
}
#Override
public void attach(OneBean object, OneEditor subEditor) {
driver.initialize(subEditor);
driver.edit(object);
}
});
return listEditor;
}

Answer 1

You're not using an EditorDriver, so the ListEditor is not initialized with an EditorChain, so chain is null, hence the NPE. Case made.
⇒ use an EditorDriver (or do not use a ListEditor)