使用 NSMeasurementFormatterUnitOptionsNaturalScale 选项强制 DNS MeasurementFormatter 获得超过 1 的值

Question

如果我们将值 100g 放入 NSUnit 并使用 NSMeasurementFormatterUnitOptionsNaturalScale 获取翻译后的字符串，则英制系统的结果为 3.52 oz。问题出在公制上，结果是 0.1 公斤，这是一个很好的价值，但我需要保持 100 克。这是一个食谱，当价值低于 1 公斤时，更常见的是保持 "g"。

用米测试不存在这个问题，100m 是公制的 100m 可能是因为米是像 kg（而不是 g）这样的基值。

有没有办法强制它的值大于 1 而不是 0,xx？

NSUnitMass *g = [NSUnitMass grams];
NSMeasurement *measurementGramm = [[NSMeasurement alloc] initWithDoubleValue:100 unit:g];
NSMeasurementFormatter *formatter = [[NSMeasurementFormatter alloc] init];
[formatter setUnitOptions:NSMeasurementFormatterUnitOptionsNaturalScale];
NSLog(@"NSMeasurementFormatterUnitOptionsNaturalScale ---------- %@", [formatter stringFromUnit:g]);

Answer 1

为方便起见，我假设储值是按公斤计算的。

NSMeasurement *measurement = [[NSMeasurement alloc] initWithDoubleValue:0.1 unit:NSUnitMass.kilograms];
NSLog(@"Measurement value = %@", measurement);

NSLog 结果

Measurement value = <NSMeasurement: 0x28028ada0> value: 0.100000 unit: kg

这里我们可以看到我们的值是0.1，单位是kg。

It's for a recipe and and it's more common to keep "g" when the value is below 1 kg.

如果 value 低于 1

，我们可以转换 unit

NSMeasurementFormatter *formatter = [[NSMeasurementFormatter alloc] init];

NSLog(@"Locale (KG) measurement value = %@", [formatter stringFromMeasurement:measurement]);

if (measurement.doubleValue < 1.0) {
    NSLog(@"Locale (G) measurement value = %@", [formatter stringFromMeasurement:[measurement measurementByConvertingToUnit:NSUnitMass.grams]]);
} else {
    NSLog(@"Locale (KG) measurement value = %@", [formatter stringFromMeasurement:measurement]);
}

NSLog 结果

Locale (KG) measurement value = 0,1 kg
Locale (G) measurement value = 0,1 kg

结果还在kg，这是unitOptions

造成的

By default, if unitOptions is set to the empty set, the formatter will do the following:

kilocalories may be formatted as "C" instead of "kcal" depending on the locale.

kilometersPerHour may be formatted as "miles per hour" for US and UK locales but "kilometers per hour" for other locales.

我们只需要改变它

formatter.unitOptions = NSMeasurementFormatterUnitOptionsProvidedUnit;

if (measurement.doubleValue < 1.0) {
    NSLog(@"Locale (G) measurement value = %@", [formatter stringFromMeasurement:[measurement measurementByConvertingToUnit:NSUnitMass.grams]]);
} else {
    NSLog(@"Locale (KG) measurement value = %@", [formatter stringFromMeasurement:measurement]);
}

NSLog 结果

Locale (G) measurement value = 100 g

完整代码

NSMeasurement *measurement = [[NSMeasurement alloc] initWithDoubleValue:0.1 unit:NSUnitMass.kilograms];
NSLog(@"Measurement value = %@", measurement);

NSMeasurementFormatter *formatter = [[NSMeasurementFormatter alloc] init];

NSLog(@"Locale (KG) measurement value = %@", [formatter stringFromMeasurement:measurement]);

if (measurement.doubleValue < 1.0) {
    NSLog(@"Locale (G) measurement value = %@", [formatter stringFromMeasurement:[measurement measurementByConvertingToUnit:NSUnitMass.grams]]);
} else {
    NSLog(@"Locale (KG) measurement value = %@", [formatter stringFromMeasurement:measurement]);
}

formatter.unitOptions = NSMeasurementFormatterUnitOptionsProvidedUnit;

if (measurement.doubleValue < 1.0) {
    NSLog(@"Locale (G) measurement value = %@", [formatter stringFromMeasurement:[measurement measurementByConvertingToUnit:NSUnitMass.grams]]);
} else {
    NSLog(@"Locale (KG) measurement value = %@", [formatter stringFromMeasurement:measurement]);
}

使用 NSMeasurementFormatterUnitOptionsNaturalScale 选项强制 DNS MeasurementFormatter 获得超过 1 的值

Force NSMeasurementFormatter to get value over 1 with NSMeasurementFormatterUnitOptionsNaturalScale optiion

xcode

objective-c

ios

nsmeasurementformatter

nsmeasurement