CreateObjcInformalDelegateWithContext

Type

handler

Summary

Create an Objective-C object with LCB implementations of methods of an informal protocol.

Syntax

CreateObjcInformalDelegateWithContext(<pProtocol>,<pHandlerMapping>,<pContext>)

Description

Use the CreateObjcInformalDelegateWithContext handler to create instances of Objective-C delegate classes with LCB implementations of protocol methods, when the Protocol object cannot be found at runtime. This occurs for example when all of the protocol methods are optional.

Instead of a protocol name (as with CreateObjcDelegateWithContext), the pProtocol argument of CreateObjcInformalDelegateWithContext must be a proper list of foreign handlers for each of the methods of the protocol for which LCB callbacks are provided in the pHandlerMapping array.

Once created an informal delegate can be set in the usual way on an instance of the appropriate class (by binding to -setDelegate:), typically so that callbacks triggered by user interaction with a widget can be handled in LCB.

If no context is required to be passed as a parameter to the callback, use CreateObjcInformalDelegate.

If the protocol can be resolved at runtime, it is generally easier to use the CreateObjcDelegateWithContext handler.

Parameters

Name	Type	Description
pProtocol		A list of foreign handlers which bind to protocol methods
pHandlerMapping		A mapping from the protocol's selector names to LCB handlers

Examples

foreign handler Objc_NSPortMessageGetMsgId(in pMessage as ObjcId) returns UInt32 \
    binds to "objc:NSPort.-msgid"

handler HandlePortMessageCallback(in pPortIndex as Integer, in pMessage as ObjcId) returns nothing
    post "portMessage" with [mPortList[pPortIndex]["name"], \
                             Objc_NSPortMessageGetMsgId(pMessage)]
end handler

foreign handler Objc_NSPortDelegateHandlePortMessage(in pTarget as ObjcId, in pPortMessage as ObjcId) returns nothing \
    binds to "objc:.-handlePortMessage:"

public handler GetNSPortDelegate(in pPortIndex as Integer)
    return CreateObjcInformalDelegateWithContext([Objc_NSPortDelegateHandlePortMessage], \
                                                 { "handlePortMessage:": \
                                                   HandlePortMessageCalback }, \
                                                 pPortIndex)
end handler

Related

handler: CreateObjcDelegate, CreateObjcDelegateWithContext, CreateObjcInformalDelegate