I'm trying to read the user set system preferences for Temperature unit (Celsius/Fahrenheit). I was trying to get this data using NSLocale but I cannot find any evidence of a temperature setting in there.
Is it even possible to read this data?
Thanks!
The official API is documented under the Preferences Utilities:
let key = "AppleTemperatureUnit" as CFString
let domain = "Apple Global Domain" as CFString
if let unit = CFPreferencesCopyValue(key, domain, kCFPreferencesCurrentUser, kCFPreferencesAnyHost) as? String {
print(unit)
} else {
print("Temperature unit not found")
}
If you wonder how I found it, I used the defaults utility in the Terminal:
> defaults find temperature
Found 1 keys in domain 'Apple Global Domain': {
AppleTemperatureUnit = Fahrenheit;
}
Found 1 keys in domain 'com.apple.ncplugin.weather': {
WPUseMetricTemperatureUnits = 1;
}
This is a bit of a hack, but you can do it this way on macOS 10.12+ and iOS 10+:
// Create a formatter.
let formatter = MeasurementFormatter()
// Create a dummy temperature, the unit doesn't matter because the formatter will localise it.
let dummyTemp = Measurement(value: 0, unit: UnitTemperature.celsius)
let unit = formatter.string(from: dummyTemp).characters.last // -> F
This outputs "F" in my playground which defaults to the US locale. But change your locale or use this code on a device and you'll get the locale specific temperature unit - or the string for it anyway.
