PHAssetImageProgressHandler
The signature for a block that Photos calls while downloading asset data from iCloud. Used by the Progresshandler property.
Declaration
typealias PHAssetImageProgressHandler = (Double, (any Error)?, UnsafeMutablePointer<ObjCBool>, [AnyHashable : Any]?) -> VoidDiscussion
If you request an image whose data is not on the local device, and you have enabled downloading with the isNetworkAccessAllowed property, Photos calls your block periodically to report progress and to allow you to cancel the download.
The block takes the following parameters:
- progress
A floating-point value indicating the progress of the download. A value of
0.0indicates that the download has just started, and a value of1.0indicates the download is complete.- error
An
NSErrorobject describing an error that occurred when attempting to download the image, ornilif no errors have occurred.- stop
A pointer to a Boolean value. To cancel the download, set
*stoptotrueinside the block.- info
A dictionary providing additional information about the status of the image request. See Image Result Info Keys for possible keys and values. For example, a
truevalue for the key PHImageResultIsDegradedKey indicates that Photos may send the full-quality version of the image later, depending on the value of the image request’s deliveryMode property.