Package apple.fileprovider.protocol

Interface NSFileProviderThumbnailing

  • public interface NSFileProviderThumbnailing
    Protocol to implement if the provider supports fetching thumbnails for its items. API-Since: 16.0

    • Method Detail

      • fetchThumbnailsForItemIdentifiersRequestedSizePerThumbnailCompletionHandlerCompletionHandler

        @NotNull
@NotNull NSProgress fetchThumbnailsForItemIdentifiersRequestedSizePerThumbnailCompletionHandlerCompletionHandler​(@NotNull
                                                                                                                 @NotNull NSArray<java.lang.String> itemIdentifiers,
                                                                                                                 CGSize size,
                                                                                                                 @NotNull
                                                                                                                 @NotNull NSFileProviderThumbnailing.Block_fetchThumbnailsForItemIdentifiersRequestedSizePerThumbnailCompletionHandlerCompletionHandler_2 perThumbnailCompletionHandler,
                                                                                                                 @NotNull
                                                                                                                 @NotNull NSFileProviderThumbnailing.Block_fetchThumbnailsForItemIdentifiersRequestedSizePerThumbnailCompletionHandlerCompletionHandler_3 completionHandler)
        The system calls this method to fetch thumbnails. The @p perThumbnailCompletionHandler should be called for each thumbnail, and [@p] completionHandler only after all the per thumbnail completion blocks. In the event of a global error, the implementation is allowed to skip calling the @p perThumbnailCompletionHandler for individual thumbnails. In that case, the @p completionHandler's error parameter would apply to all item identifiers for which @p perThumbnailCompletionHandler had not been called. If there is no thumbnail for a given item, the @p perThumbnailCompletionHandler should be called with its @p imageData and @p error parameters both set to nil. If the system decides that an in-flight thumbnail request is not needed anymore, it will call the returned @p NSProgress object's @p -cancel method, at which time the implementation should clean up any held resources. The system will cache the thumbnail for the item, and the cache will be invalidated when itemVersion.contentVersion changes. Thread safety: ------------ The @p perThumbnailCompletionHandler may be called from multiple threads concurrently. Cancellations: ------------ If the NSProgress returned by this method is cancelled, the extension should call the completion handler with (NSUserCancelledError) in the NSProgress cancellation handler. Execution time: --------------- This method is not expected to take more than a few tens seconds to complete the retrieval of the services exposed on the item. The system will call `cancel` on the progress if the operation takes too much time. The extension is then expected to quickly call the completion handler.