Instance Method


Returns a file extension to append to the file URL of the document file being written.


func fileNameExtension(forType typeName: String?, saveOperation: UIDocumentSaveOperation) -> String



A Uniform Type Identifier (UTI) that indicates the type of document (for example, PDF or HTML).


A constant that indicates whether the document file is being written the first time or whether it is being overwritten. See UIDocumentSaveOperation for details.

Return Value

A string to use as the file extension of the document file.


The default implementation queries Launch Services to obtain the file extension matching the file (document) type. You can override this method to return a file extension that is different from the default extension. The default implementation of the save(to:for:completionHandler:) method calls this method before it gets the document content and writes the document file to disk.

See Also

Related Symbols

func fileAttributesToWrite(to: URL, for: UIDocumentSaveOperation)

Returns a dictionary of file attributes to associate with the document file when writing or updating it.