Now I have a project on GWT with UIBinder and I need to integrate SmartGWT into it. If I'm just trying to add SmartGWT components to ui.xml and view class as plain GWT components, I get an error when compiling. What additional actions should I make for using the SmartGWT widgets?
SmartGWT doesn't provide UiBinder support. But you can use uibinding-smartgwt. A project to adapt SmartGWT for UiBinder.
Then just add xmlns:zs="urn:import:org.synthful.smartgwt.client.widgets" on your UiBind xml.
More info here