ckarthikv / wit-ios-sdk

Wit.ai iOS SDK

Wit-iOS 4.1.0

The wit.ai iOS SDK is the easiest way to integrate wit.ai features into your iOS application.

The SDK can capture intents and entities from:

• the microphone of the device
• text

Link to the SDK

Using CocoaPods

Add the following dependency to your Podfile:

pod 'Wit', '~> 4.1.0'

And then run the following command in your project home directory:

pod install

Using Wit.framework

You can download an archive containing the the .framework and the .bundle files under the release section.

How to use

You will find on our website a quick start guide of our iOS SDK and a fully detailed API reference: https://wit.ai/docs/ios/4.0.0

API

@property and static methods

Delegate to send feedback for the application
@property(nonatomic, strong) id <WitDelegate> delegate;

Access token used to contact Wit.ai
@property (strong) NSString* accessToken;

Configure the voice activity detection algorithm:
- WITVadConfigDisabled
- WITVadConfigDetectSpeechStop (default)
- WITVadConfigFull
@property WITVadConfig detectSpeechStop;

Set the maximum length of time recorded by the VAD in ms
- Set to -1 for no timeout
- Defaults to 7000
@property int vadTimeout;

Set VAD sensitivity (0-100)
- Lower values are for strong voice signals like for a cellphone or personal mic
- Higher values are for use with a fixed-position mic or any application with voice burried in ambient noise
- Defaults to 0
@property int VadSensitivity;

Singleton instance accessor.
+ (Wit*)sharedInstance;

Understanding text

InterpretString
Sends an NSString to wit.ai for interpretation. Same as sending a voice input, but with text.
- (void) interpretString: (NSString *) string customData:(id)customData;

Recording audio

Starts a new recording session. [self.delegate witDidGraspIntent:…] will be called once completed.
- (void)start;

Same as the start method but allow a custom object to be passed, which will be passed back as an argument of the
[self.delegate witDidGraspIntent:… customData:(id)customData]. This is how you should link a request to a response, if needed.
- (void)start: (id)customData;

Stops the current recording if any, which will lead to [self.delegate witDidGraspIntent:…] call.
- (void)stop;

Start / stop the audio processing. Once the API response is received, [self.delegate witDidGraspIntent:…] method will be called.
- (void)toggleCaptureVoiceIntent;

Same as toggleCaptureVoiceIntent, allowing you to pass a customData object to the [self start:(id)customData] function.
- (void)toggleCaptureVoiceIntent:(id) customData;

YES if Wit is recording.
- (BOOL)isRecording;

Context

Sets context from NSDictionary. Merge semantics!
See the context documentation in our doc for for more information: Context documentation
- (void)setContext:(NSDictionary*)dict;
Returns the current context.
- (NSDictionary*)getContext;

Implementing the WitDelegate protocol

/**
 * Protocol used by Wit to communicate with the app
 */
@protocol WitDelegate <NSObject>

   /**
    * Called when the Wit request is completed.
    * param outcomes a NSDictionary of outcomes returned by the Wit API. Outcomes are ordered by confidence, highest first. Each outcome contains (at least) the following keys:
    *       intent, entities[], confidence, _text. For more information please refer to our online documentation: https://wit.ai/docs/http/20141022#get-intent-via-text-link
    *
    * param messageId the message id returned by the api
    * param customData any data attached when starting the request. See [Wit sharedInstance toggleCaptureVoiceIntent:... (id)customData] and [[Wit sharedInstance] start:... (id)customData];
    * param error Nil if no error occurred during processing
    */
   - (void)witDidGraspIntent:(NSArray *)outcomes messageId:(NSString *)messageId customData:(id) customData error:(NSError*)e;

@optional

/**
 * When using the hands free voice activity detection option (WITVadConfigFull), this callback will be called when the microphone started to listen
 * and is waiting to detect voice activity in order to start streaming the data to the Wit API.
 * This function will not be called if the [Wit sharedInstance].detectSpeechStop is not equal to WITVadConfigFull
 */
- (void)witActivityDetectorStarted;

/**
 * Called when the streaming of the audio data to the Wit API starts.
 * The streaming to the Wit API starts right after calling one of the start methods when
 * detectSpeechStop is equal to WITVadConfigDisabled or WITVadConfigDetectSpeechStop.
 * If detectSpeechStop is equal to WITVadConfigFull, the streaming to the Wit API starts only when the SDK
 * detected a voice activity.
 */
- (void)witDidStartRecording;

/**
 Called when Wit stop recording the audio input.
 */
- (void)witDidStopRecording;

/**
 Called whenever Wit reveices an audio chunk. The format of the returned audio is 16-bit PCM, 16 kHz mono.
 */
- (void)witDidGetAudio:(NSData *)chunk;

 @end

Notifications

// A NSNotification is sent on the default center when the power of the audio signal changes
NSNumber *newPower = [[NSNumber alloc] initWithFloat:power];
[[NSNotificationCenter defaultCenter] postNotificationName:kWitNotificationAudioPowerChanged object:newPower];        

Constants

static NSString* const kWitNotificationAudioPowerChanged = @"WITAudioPowerChanged";
static int const kWitAudioSampleRate = 16000;
static int const kWitAudioBitDepth = 16;