Added in API level 30

NumberFormatter

public final class NumberFormatter
extends Object

java.lang.Object
   ↳ android.icu.number.NumberFormatter


All-in-one formatter for localized numbers, currencies, and units. For a full list of options, see NumberFormatterSettings.

 // Most basic usage:
 NumberFormatter.withLocale(...).format(123).toString();  // 1,234 in en-US

 // Custom notation, unit, and rounding strategy:
 NumberFormatter.with()
     .notation(Notation.compactShort())
     .unit(Currency.getInstance("EUR"))
     .precision(Precision.maxDigits(2))
     .locale(...)
     .format(1234)
     .toString();  // \u20ac1.2K in en-US

 // Create a formatter in a private static final field:
 private static final LocalizedNumberFormatter formatter = NumberFormatter.withLocale(...)
     .unit(NoUnit.PERCENT)
     .precision(Precision.fixedFraction(3));
 formatter.format(5.9831).toString();  // 5.983% in en-US

 // Create a "template" in a private static final field but without setting a locale until the call site:
 private static final UnlocalizedNumberFormatter template = NumberFormatter.with()
     .sign(SignDisplay.ALWAYS)
     .unitWidth(UnitWidth.FULL_NAME);
 template.locale(...).format(new Measure(1234, MeasureUnit.METER)).toString();  // +1,234 meters in en-US
 

This API offers more features than DecimalFormat and is geared toward new users of ICU.

NumberFormatter instances (i.e., LocalizedNumberFormatter and UnlocalizedNumberFormatter) are immutable and thread safe. This means that invoking a configuration method has no effect on the receiving instance; you must store and use the new number formatter instance it returns instead.

 UnlocalizedNumberFormatter formatter = UnlocalizedNumberFormatter.with()
         .notation(Notation.scientific());
 formatter.precision(Precision.maxFraction(2)); // does nothing!
 formatter.locale(ULocale.ENGLISH).format(9.8765).toString(); // prints "9.8765E0", not "9.88E0"
 

This API is based on the fluent design pattern popularized by libraries such as Google's Guava. For extensive details on the design of this API, read the design doc.

Summary

Public methods

static UnlocalizedNumberFormatter with()

Call this method at the beginning of a NumberFormatter fluent chain in which the locale is not currently known at the call site.

static LocalizedNumberFormatter withLocale(Locale locale)

Call this method at the beginning of a NumberFormatter fluent chain in which the locale is known at the call site.

static LocalizedNumberFormatter withLocale(ULocale locale)

Call this method at the beginning of a NumberFormatter fluent chain in which the locale is known at the call site.

Inherited methods

Public methods

with

Added in API level 30
public static UnlocalizedNumberFormatter with ()

Call this method at the beginning of a NumberFormatter fluent chain in which the locale is not currently known at the call site.

Returns
UnlocalizedNumberFormatter An UnlocalizedNumberFormatter, to be used for chaining.

withLocale

Added in API level 30
public static LocalizedNumberFormatter withLocale (Locale locale)

Call this method at the beginning of a NumberFormatter fluent chain in which the locale is known at the call site.

Parameters
locale Locale: The locale from which to load formats and symbols for number formatting.

Returns
LocalizedNumberFormatter A LocalizedNumberFormatter, to be used for chaining.

withLocale

Added in API level 30
public static LocalizedNumberFormatter withLocale (ULocale locale)

Call this method at the beginning of a NumberFormatter fluent chain in which the locale is known at the call site.

Parameters
locale ULocale: The locale from which to load formats and symbols for number formatting.

Returns
LocalizedNumberFormatter A LocalizedNumberFormatter, to be used for chaining.