Added in API level 30
Summary: Methods | Inherited Methods

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.

Note: To format monetary/currency values, specify the currency in the `.unit()` function.

Summary