iOS图表ValueFormatter [英] iOS Charts ValueFormatter

问题描述

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

I am using iOS charts plugin (line chart) and wish to style the chart values (the number above each point) to a decimal number.

该值为双精度，但是默认情况下，图表会对其进行四舍五入并将其显示为整数.

The value is a double, but charts by default is rounding it and displaying it as an integer.

我尝试了以下操作，但不起作用:

I have tried the following but not working:

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

我尝试了其他各种属性，但没有一个会更改数据集中数字的格式.

I have tried various other properties but non of them change the format of the number in the dataset.

如何更改显示号码的格式?

How can I change the format of the displayed number?

推荐答案

几乎在这里，只需添加以下类:

Almost there, just need to add the following class:

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)!
    }
}

现在将其用作数字格式器:

Now use this as the number formatter:

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

这篇关于iOS图表ValueFormatter的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！