Class

Formatter

An abstract class that declares an interface for objects that create, interpret, and validate the textual representation of values.

Declaration

class Formatter : NSObject

Overview

Subclassing Notes

NSFormatter is intended for subclassing. A custom formatter can restrict the input and enhance the display of data in novel ways. For example, you could have a custom formatter that ensures that serial numbers entered by a user conform to predefined formats. Before you decide to create a custom formatter, make sure that you cannot configure the public subclasses to satisfy your requirements.

For instructions on how to create your own custom formatter, see Creating a Custom Formatter.

Topics

Getting Textual Representations of Object Values

func string(for: Any?) -> String?

The default implementation of this method raises an exception.

func attributedString(for: Any, withDefaultAttributes: [NSAttributedString.Key : Any]?) -> NSAttributedString?

The default implementation returns nil to indicate that the formatter object does not provide an attributed string.

func editingString(for: Any) -> String?

The default implementation of this method invokes string(for:).

Getting Object Values for Textual Representations

Validating Partial Strings

func isPartialStringValid(AutoreleasingUnsafeMutablePointer<NSString>, proposedSelectedRange: NSRangePointer?, originalString: String, originalSelectedRange: NSRange, errorDescription: AutoreleasingUnsafeMutablePointer<NSString?>?) -> Bool

This method should be implemented in subclasses that want to validate user changes to a string in a field, where the user changes are not necessarily at the end of the string, and preserve the selection (or set a different one, such as selecting the erroneous part of the string the user has typed).

Constants

enum Formatter.Context

The formatting context for a formatter.

enum Formatter.UnitStyle

Specifies the width of the unit, determining the textual representation.

Relationships

Inherits From