Announcement

**ecruz** · 14 Mar 2013, 10:36

Correction on the build

This problem is occurring on the 2/27 build.

**Isomorphic** · 14 Mar 2013, 11:45

We can't reproduce this. Below is some sample code that shows the API working as expected.

Can you show how you're ending up with a FormItem being returned?

Code:

    	ComboBoxItem cbItem = new ComboBoxItem();
        cbItem.addChangedHandler(new ChangedHandler() {
            @Override
            public void onChanged(ChangedEvent event) {
                    ComboBoxItem myCB = new ComboBoxItem(event.getItem().getJsObj());
                    CanvasItem myCanvasItem = myCB.getForm().getCanvasItem();

                    if (myCB.getValue()!=null)
                            myCanvasItem.storeValue(myCB.getValueAsString());
            }
        });

        DynamicForm form = new DynamicForm();
        form.setItemLayout(FormLayoutType.ABSOLUTE);
        form.setNumCols(1);
        form.setFields(cbItem);
        
        CanvasItem canvasItem = new CanvasItem();
        canvasItem.setCanvas(form);
        
        DynamicForm form2 = new DynamicForm();
        form2.setFields(canvasItem);
        form2.draw();

**bbruyn** · 15 Mar 2013, 10:44

I work with ecruz, and he asked me to take a look at what was going on. I've fixed it for him, but I'm not entirely sure whether it should have worked the way it was or not. I think I know what you're going to say, and if I'm right, I'll probably post a follow-up thread for clarification.

Anyway.

There's a dataSoureField declared with an editorType attribute like so:

Code:

<field name="itemVendor" ... editorType="MyCustomCanvasItem"/>

and then there's this thing in the EntryPoint that iterates over every field in every datasource, after they've been loaded, checks for that editorType attribute, and calls DataSourceField.setEditorType.

Code:

if ("MyCustomCanvasItem".equals(editorType)) {
  field.setEditorType(new MyCustomCanvasItem());
}

Finally, there was a DynamicForm that wanted to bind to one of these altered DataSourceFields

Code:

DynamicForm form = new DynamicForm();
form.setDataSource("Item");
form.setFields(new FormItem("itemVendor"));

where the expectation was that the new FormItem was going to get the DataSourceField's metadata, including the editorType. Well, it does get the editorType, clearly. It's just that the type cast was returning a FormItem and not its editorType.

Can you confirm what the behavior should have been? And perhaps whether it's better to

Code:

FormItem item = new FormItem("itemVendor");
item.setEditorType(new MyCustomCanvasItem());
form.setFields(item);

or

Code:

MyCustomCanvasItem item = new MyCustomCanvasItem("itemVendor"));
form.setFields(item);

**Isomorphic** · 15 Mar 2013, 11:14

Right, your latter code snippets are the right approach. When you provide a FormItem like that, we take you seriously that that's the type you want to use. Consider if you had provided an instance of "MyEvenMoreCustomCanvasItem" - you would expect that to override editorType from the DataSource.

Just as an aside, we will soon have support for specifying editorType as the FQN of a custom Java subclass of FormItem in the DataSource file. This has been a while coming since we basically had to build the equivalent of Java reflection into GWT.

**s.csaba** · 19 Sep 2014, 08:06

Originally posted by Isomorphic View Post

Just as an aside, we will soon have support for specifying editorType as the FQN of a custom Java subclass of FormItem in the DataSource file. This has been a while coming since we basically had to build the equivalent of Java reflection into GWT.

Hello, Isomorphic!

Is there any advance for this reflection feature since then?

**Isomorphic** · 19 Sep 2014, 10:36

Yes, just take a look at the updated docs for DataSourceField.editorType.

Announcement

ClassCastException with getCanvasItem()

Comment

Comment

Comment

Comment

Comment

Comment