Activity starter code error (extension)

[Kumaraswamy]

Also check this :

Cannot find symbol error in extension

The problem is obvious. From where are you accessing the container variable ? You need to declare container variable in the extension class then assign the value from the constructor. public class ExtensionTemplate extends AndroidNonvisibleComponent { private ComponentContainer container; public ExtensionTemplate(ComponentContainer container) { super(container.$form()); this.container = container; }