activityImage
An image that identifies the service to the user.
Declaration
var activityImage: UIImage? { get }Discussion
The default value is nil. Subclasses must override this property to return a valid image object that can be presented to the user. The UIActivityViewController object uses this image to generate a button for your service in its UI.
The alpha channel of the image is used as a mask to generate the final image that’s presented to the user. Any color data in the image itself is ignored. Opaque pixels have a gradient applied to them, and this gradient is then laid on top of a standard background. Thus, a completely opaque image would yield a gradient-filled rectangle.
For iPhone and iPod touch, images on iOS 7 should be 60 by 60 points; on earlier versions of iOS, you should use images no larger than 43 by 43 points. For iPad, images on iOS 7 should be 76 by 76 points; on earlier versions of iOS, you should use images no larger than 60 by 60 points. On a device with Retina display, the number of pixels is doubled in each direction.