Question 66474 in IOS Swift Question posted in
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Displaying Volume as milliliter/floz – Ios swift

I’m hoping someone can help me with this issue that’s driving me nuts.

I want to use the formatted() modifier with Measurements so I can get locale specific units, and it’s working great for mass and temperature.

I correctly get oz/g and F/C but for volume I’m getting cm3/in3 instead of ml/floz.
I realize that is a Volumetric unit, but It’s not the one i want.

Text("(Measurement(value: Double(volume), unit: UnitVolume.milliliters).formatted())")
Text("(Measurement(value: Double(mass), unit: UnitMass.grams).formatted())")
Text("(Measurement(value: Double(temp), unit: UnitTemperature.celsius).formatted())")

I know I can do this

Text("(Measurement(value: Double(brew.water), unit: UnitVolume.milliliters).formatted(.measurement(width: .abbreviated, usage: .asProvided, numberFormatStyle: .number)))")

But then I have to figure out the locale myself.
Is there a way to this with the builtins in swiftui?

Thanks in advance

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2

Answers


  1. 0

    Your last attempt is close. Just change the usage to .liquid instead of asProvided.

    Text("(Measurement(value: Double(brew.water), unit: UnitVolume.milliliters).formatted(.measurement(width: .abbreviated, usage: .liquid, numberFormatStyle: .number)))")

    This gives me the result as "fl oz" with a locale of en_US.

    Note that MeasurementFormatUnitUsage<UnitVolume>.liquid is only available as of iOS 16.0 so this solution won’t work with iOS 15.

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  2. 0

    You can use converted and MeasurementFormatter

    In its simplest form it would look something like

    struct VolumeSampleView: View {
    let volume = Measurement(value: 10, unit: UnitVolume.liters)
    var body: some View {
        Text(volume.converted(to: .milliliters), formatter: MeasurementFormatter())
    }
}

    But in an extension you can add customizations that can be reused and it works similar to formatted but allows for iOS 14+.

    extension Formatter{
    static func measurement(unitOptions: MeasurementFormatter.UnitOptions = .providedUnit, unitStyle: Formatter.UnitStyle = .short, numberStyle: NumberFormatter.Style = .decimal) -> MeasurementFormatter{
        
        let f = MeasurementFormatter()
        f.unitOptions = unitOptions
        f.unitStyle = unitStyle
        
        let nf = NumberFormatter()
        nf.numberStyle = numberStyle
        
        f.numberFormatter = nf
        
        return f
    }
}

    And then your View would evolve to look something like

    struct VolumeSampleView: View {
    let volume = Measurement(value: 10, unit: UnitVolume.liters)
    let mass = Measurement(value: 10, unit: UnitMass.kilograms)
    var body: some View {
        Text(volume.converted(to: .milliliters), formatter: .measurement())
        Text(mass.converted(to: .grams), formatter: .measurement())

    }
}

    You can also extend Measurement itself and add a method that provides the string automatically.

    extension Measurement{
    func toString(unitOptions: MeasurementFormatter.UnitOptions = .providedUnit, unitStyle: Formatter.UnitStyle = .short, numberStyle: NumberFormatter.Style = .decimal) -> String{
        
        let f = Formatter.measurement(unitOptions: unitOptions, unitStyle: unitStyle, numberStyle: numberStyle)
        return f.string(from: self)
    }
}

    Then you don’t have to use formatter you can just call toString() which would allow for an answer that works with all SwiftUI versions.

    struct VolumeSampleView: View {
    let volume = Measurement(value: 10, unit: UnitVolume.liters)
    let mass = Measurement(value: 10, unit: UnitMass.kilograms)
    let temp = Measurement(value: 30, unit: UnitTemperature.fahrenheit)
    var body: some View {
        VStack{
            Text(volume.converted(to: .milliliters).toString())
            Text(volume.converted(to: .fluidOunces).toString())
            Text(mass.converted(to: .grams).toString())
            Text(temp.converted(to: .celsius).toString())
        }
    }
}

    enter image description here

    To show locale adjusted measurements you can just add .current to the Locale

    extension Formatter{
    static func measurement(unitOptions: MeasurementFormatter.UnitOptions? = .providedUnit, unitStyle: Formatter.UnitStyle = .short, numberStyle: NumberFormatter.Style = .decimal) -> MeasurementFormatter{
        
        let f = MeasurementFormatter()
        f.unitStyle = unitStyle
        
        if let options = unitOptions{ //Make unitOptions optional
            f.unitOptions = options
        }
        
        f.locale = .current //Add locale consideration

        let nf = NumberFormatter()
        nf.numberStyle = numberStyle
        
        f.numberFormatter = nf
        
        return f
    }
}
extension Measurement{
    func toString(unitOptions: MeasurementFormatter.UnitOptions? = .providedUnit, unitStyle: Formatter.UnitStyle = .short, numberStyle: NumberFormatter.Style = .decimal) -> String{
        
        let f = Formatter.measurement(unitOptions: unitOptions, unitStyle: unitStyle, numberStyle: numberStyle)
        return f.string(from: self)
    }
}

    Then just set the unitOptions argument to nil when you want the units to show adjusted by locale

    Text(volume.toString(unitOptions: nil)) //Will show locale specific version
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