Using locale settings to detect wheter to use imperial units

In the end I went for the following solution.

public class UnitLocale {    public static UnitLocale Imperial = new UnitLocale();    public static UnitLocale Metric = new UnitLocale();    public static UnitLocale getDefault() {            return getFrom(Locale.getDefault());    }    public static UnitLocale getFrom(Locale locale) {        String countryCode = locale.getCountry();        if ("US".equals(countryCode)) return Imperial; // USA        if ("LR".equals(countryCode)) return Imperial; // Liberia        if ("MM".equals(countryCode)) return Imperial; // Myanmar        return Metric;    }}

Use it like this for example.

if (UnitLocale.getDefault() == UnitLocale.Imperial) convertToimperial();

If convert methods are also need they can preferably be added to subclasses of UnitLocale. I only needed to detect wheter to use imperial units and send it to the server.

Using ints over java objects have extremely slim performance gains and makes the code harder to read. Comparing two references in java is comparable in speed to comparing two ints. Also using objects allow us to add methods to the UnitLocale class or subclasses such as, convertToMetric, etc.

You could also use an enum instead if you prefer that.

A more or less complete way to do this is this way.

Kotlin:

private fun Locale.toUnitSystem() =    when (country.toUpperCase()) {        // https://en.wikipedia.org/wiki/United_States_customary_units        // https://en.wikipedia.org/wiki/Imperial_units        "US" -> UnitSystem.IMPERIAL_US        // UK, Myanmar, Liberia,         "GB", "MM", "LR" -> UnitSystem.IMPERIAL        else -> UnitSystem.METRIC    }

Note that there is a difference between UK and US imperial systems, see the wiki articles for more details.

Building on the other nice solutions here, you can also implement this as a Kotlin extension function to the Locale object:

fun Locale.isMetric(): Boolean {    return when (country.toUpperCase(this)) {        "US", "LR", "MM" -> false        else -> true    }}

This way, all you need to do is call:

val metric = Locale.getDefault().isMetric()