handler(for:)

handler(for:)

handler(for:) Instance Method of INIntentHandlerProviding Returns the object capable of handling the specified intent in an extension.

func handler(for intent: INIntent) -> Any?

Parameters

• intent: The intent object representing the request coming from the system.

Return Value

The object capable of handling the specified intent, or nil if your app doesn’t handle the intent. Return an object that conforms to the protocol for handling intents of the same type as the provided intent.

Discussion

This method acts as a dispatcher, mapping incoming intents to the object capable of handling them. In your implementation, check the intent parameter’s type and return an object capable of handling that type. As SiriKit invokes this method on an arbitrary queue, limit your implementation to just resolving the handler, and dispatch additional work to an alternate queue.

The object you return must adopt the handling protocol for the specified intent. For example, when receiving an INSendMessageIntent object, return an object that adopts INSendMessageIntentHandling. The simplest way to implement this method is to check the intent parameter’s type and return the appropriate object, as shown in the following example.

Swift:

override func handler(for intent: INIntent) -> Any? {        
    switch intent {
    case is INSendMessageIntent:
        return SendMessageHandler()
    case is INSearchForMessagesIntent:
        return SearchForMessagesHandler()
    default:
        return nil
    }
}

Objective-C:

- (nullable id)handlerForIntent:(INIntent *)intent {
 
   // You can substitute other objects for self based on the specific intent
   if ([intent isKindOfClass:[INSendMessageIntent class]]) {
       return ([[SendMessageHandler alloc] init]);
   }
   else if ([intent isKindOfClass:[INSearchForMessagesIntent class]]) {
       return ([[SearchForMessagesHandler alloc] init]);
   }
   return nil;
}

You’re responsible for providing the handler objects and for ensuring they adopt the necessary protocols to respond to a given intent. In the example above, the SendMessageHandler class implements the INSendMessageIntentHandling protocol, and the SearchForMessagesHandler class implements the INSearchForMessagesIntentHandling protocol.

When creating handler objects in this method, use the provided intent object only to determine which handler to create. Don’t use the intent object to initialize your handler object and don’t store a reference to the intent object for later use. SiriKit updates the intent object during the processing of the request to incorporate any new information provided by the user.

The system calls this INExtension method for intents listed in the Supported Intents section of an extension’s target. To handle intents in your app directly, see application(:handlerFor:)).

For information about how to handle intents, see Resolving and Handling Intents.