AVCaptureMetadataOutputObjectsDelegate Protocol Reference
Available in iOS 6.0 and later.
The delegate of an
AVCaptureMetadataOutput object must adopt the
AVCaptureMetadataOutputObjectsDelegate protocol. The single method in this protocol is optional. It allows a delegate to respond when a capture metadata output object receives relevant metadata objects through its connection.
AVCaptureMetadataOutput object calls the methods of your delegate object on the dispatch queue associated with its
Processing Emitted Metadata Objects
Tells the delegate that the capture metadata output object emitted new metadata objects.
AVCaptureMetadataOutputobject that captured and emitted the metadata objects.
An array of
AVMetadataObjectinstances representing the newly emitted metadata. Because
AVMetadataObjectis an abstract class, the objects in this array are always instances of a concrete subclass.
The capture connection through which the objects were emitted.
AVCaptureMetadataOutput object emits only metadata objects whose types are included in its
metadataObjectTypes property. Your delegate can implement this method and use it to perform additional processing on those metadata objects as they become available. If you plan to use metadata objects outside of the scope of this method, you must store strong references to them and remove those references when you no longer need the objects.
This method is executed on the dispatch queue specified by the
metadataObjectsCallbackQueue property of the capture metadata output object. Because this method may be called frequently, your implementation should be efficient to prevent capture performance problems, including dropped metadata objects.
- Available in iOS 6.0 and later.
© 2012 Apple Inc. All Rights Reserved. (Last updated: 2012-09-19)