The signature for a block that Photos calls while downloading asset data from iCloud. Used by the
- iOS 8+
- macOS 10.13+
- UIKit for Mac 13.0+Beta
- tvOS 10+
If you request an image whose data is not on the local device, and you have enabled downloading with the
is property, Photos calls your block periodically to report progress and to allow you to cancel the download.
The block takes the following parameters:
A floating-point value indicating the progress of the download. A value of
0indicates that the download has just started, and a value of
1indicates the download is complete.
NSErrorobject describing an error that occurred when attempting to download the image, or
nilif no errors have occurred.
A pointer to a Boolean value. To cancel the download, set
trueinside the block.
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
PHImageindicates that Photos may send the full-quality version of the image later, depending on the value of the image request’s
Result Is Degraded Key