Declares a callback_symbol to handle callback_name from the template XML defined for widget_type. See Builder.addCallbackSymbol.
Note that this must be called from a composite widget classes class initializer after calling Widget.classSetTemplate.
The name of the callback as expected in the template XML
The callback symbol
3.10
Declares a callback_symbol to handle callback_name from the template XML defined for widget_type. See Builder.addCallbackSymbol.
Note that this must be called from a composite widget classes class initializer after calling Widget.classSetTemplate.