When building an iOS Binding Library project with a Swift Protocol as a parameter for a function, or exposing one as a public field, The type or namespace name 'xxx' could not be found (are you missing a using directive or an assembly reference?) is thrown, even though xxx is defined in ApiDefinition.cs (syntax generated with sharpie)
example:
Swift:
@objc(ScanOperation)
public protocol ScanOperation {
@obj(onItemAdded:)
func onItemAdded(itemObj: ItemData)
}
@objc(ScanAgent)
public class ScanAgent : NSObject {
@objc(Initialize:)
public func Initialize(scanOperation: ScanOperation) { }
}
Generated sharpie syntax in ApiDefinitions:
[Protocol]
interface ScanOperation
{
// @required -(void)onItemAdded:(ItemData * _Nonnull)itemObj;
[Abstract]
[Export("onItemAdded:")]
void OnItemAdded(ItemData itemObj);
}
// @interface ScanAgent : NSObject
[BaseType(typeof(NSObject))]
interface ScanAgent
{
// -(void)Initialize:(id<ScanOperation> _Nonnull)scanOperation;
[Export("Initialize:")]
void Initialize(ScanOperation scanOperation);
}
This will not compile, and the above error will appear.
This happens because the generated code creates an interface with an I prefix.
/obj/(Debug/Release)/iOS/<proj>/ScanOperation.g.cs contains the following:
public partial interface IScanOperation : INativeObject, IDisposable
So ScanOperation does not exist in the generated code.
What needs to be done is to add an empty interface in ApiDefinition.cs and replace the signature of the function/field.
In the above example:
interface IScanOperation { }
// @interface ScanAgent : NSObject
[BaseType(typeof(NSObject))]
interface ScanAgent
{
// -(void)Initialize:(id<ScanOperation> _Nonnull)scanOperation;
[Export("Initialize:")]
void Initialize(IScanOperation scanOperation);
}
More information can be found here under Binding protocols section.