iOS图表ValueFormatter

Question

我正在使用iOS图表插件（折线图），并希望将图表值（每个点上方的数字）设置为十进制数。

该值为double，但默认情况下，图表会将其四舍五入并显示为整数。

我尝试过以下但不能正常工作：

    let valueformatter = NumberFormatter()
    valueformatter.numberStyle = .decimal
    valueformatter.locale = Locale.current
    lineChartDataSet.valueFormatter = valueformatter as? IValueFormatter

我尝试过各种其他属性，但不会更改数据集中数字的格式。

如何更改显示数字的格式？

Answer 1

几乎就在那里，只需要添加以下类：

class ChartValueFormatter: NSObject, IValueFormatter {
    fileprivate var numberFormatter: NumberFormatter?

    convenience init(numberFormatter: NumberFormatter) {
        self.init()
        self.numberFormatter = numberFormatter
    }

    func stringForValue(_ value: Double, entry: ChartDataEntry, dataSetIndex: Int, viewPortHandler: ViewPortHandler?) -> String {
        guard let numberFormatter = numberFormatter
            else {
                return ""
        }
        return numberFormatter.string(for: value)!
    }
}

现在使用它作为数字格式化程序：

let numberFormatter = NumberFormatter()
numberFormatter.numberStyle = .decimal
numberFormatter.locale = Locale.current
let valuesNumberFormatter = ChartValueFormatter(numberFormatter: numberFormatter)
lineChartDataSet.valueFormatter = valuesNumberFormatter
lineChartDataSet.valueFont = lineChartDataSet.valueFont.withSize(chartFontPointSize)

Answer 2

   lineChartDataSet.valueFormatter = DefaultValueFormatter(decimals: 2)

Answer 3

 let data = PieChartData(dataSet: set) 

 let formatter = NumberFormatter() 
 formatter.numberStyle = .percent 
 formatter.maximumFractionDigits = 2 
 formatter.multiplier = 1.0 
 formatter.percentSymbol = "%" 
 formatter.zeroSymbol = "" 
 data.setValueFormatter(DefaultValueFormatter(formatter: formatter))

Answer 4

这对我有用：

快速5

let valFormatter = NumberFormatter()
valFormatter.numberStyle = .currency
valFormatter.maximumFractionDigits = 2
valFormatter.currencySymbol = "$"

lineChartPrice.leftAxis.valueFormatter = DefaultAxisValueFormatter(formatter: valFormatter)