Swift 图表 X 轴不显示？答案

【问题标题】：Swift Charts X-Axis Not Displaying?Swift 图表 X 轴不显示？
【发布时间】：2018-03-16 13:21:07
【问题描述】：

我正在使用 Swift Charts 为应用创建图表，但似乎无法显示 X 轴标签。

图表配置如下：

func configure (dataPoints: [String], values: [Double]) {
    ChartIMG.noDataText = "Please Insert Some Data!"
    ChartIMG.xAxis.valueFormatter = IndexAxisValueFormatter(values: dataPoints)
    ChartIMG.xAxis.granularityEnabled = true
    ChartIMG.xAxis.granularity = 1


    ChartIMG.animate(xAxisDuration: 2.0, yAxisDuration: 2.0, easingOption: .easeInBounce)

    print(dataPoints)

    var dataEntries: [BarChartDataEntry] = []

    for i in 0..<dataPoints.count {
        let dataEntry = BarChartDataEntry(x: Double(i), y: values[i])
        dataEntries.append(dataEntry)
    }

    let chartDataSet = BarChartDataSet(values: dataEntries, label: nil)
    ChartIMG.chartDescription?.enabled = false
    self.ChartIMG.legend.enabled = false
    let chartData = BarChartData(dataSet: chartDataSet)
    ChartIMG.data = chartData


}

数据集如下：

数据点：moodList = ["Great", "Good", "Meh", "Sad", "Awful"]

值：valueList = [1.0, 2.0, 3.0, 1.0, 3.0]

图表 X 轴目前没有显示任何内容，我似乎无法弄清楚为什么？非常感谢任何帮助。

【问题讨论】：

标签： ios swift swiftcharts

【解决方案1】：

您必须使用IAxisValueFormatter 来显示 xAxis 上的值

我创建了关注类

class BarChartFormatter: NSObject,IAxisValueFormatter,IValueFormatter {


    var values : [String]
    required init (values : [String]) {
        self.values = values
        super.init()
    }


    func stringForValue(_ value: Double, axis: AxisBase?) -> String {
        return values[Int(value)]

    }

    func stringForValue(_ value: Double, entry: ChartDataEntry, dataSetIndex: Int, viewPortHandler: ViewPortHandler?) -> String {
        return values[Int(entry.x)]

    }
}

如下所示更新您的方法

   for i in 0..<dataPoints.count {
    let dataEntry = BarChartDataEntry(x: Double(i), y: values[i])
    dataEntries.append(dataEntry)
} 


let chartDataSet = BarChartDataSet(values: dataEntries, label: nil)
ChartIMG.chartDescription?.enabled = false
self.ChartIMG.legend.enabled = false

let formatter = BarChartFormatter(values: dataPoints)
let xAxis = XAxis()
xAxis.valueFormatter = formatter
ChartIMG.xAxis.valueFormatter = xAxis.valueFormatter

let chartData = BarChartData(dataSet: chartDataSet)
ChartIMG.data = chartData

希望对你有帮助

或

我已经创建了一个可以使用的扩展只需复制并粘贴新的 swift 文件

import  Charts


extension BarChartView {

    private class BarChartFormatter: NSObject,IAxisValueFormatter {

        var values : [String]
        required init (values : [String]) {
            self.values = values
            super.init()
        }


        func stringForValue(_ value: Double, axis: AxisBase?) -> String {
            return values[Int(value)]
        }
    }

    func setChartValues (xAxisValues : [String] , values : [Double],label : String) {

        var barChartDataEntries = [BarChartDataEntry]()

        for i in 0..<values.count {
            let dataEntry = BarChartDataEntry(x: Double(i), y: values[i])
            barChartDataEntries.append(dataEntry)
        }
        let chartDataSet = BarChartDataSet(values: barChartDataEntries, label: label)
        chartDataSet.colors = ChartColorTemplates.colorful()
        let chartData = BarChartData(dataSet: chartDataSet)

        let formatter = BarChartFormatter(values: xAxisValues)
        let xAxis = XAxis()
        xAxis.valueFormatter = formatter
        self.xAxis.valueFormatter = xAxis.valueFormatter
        self.xAxis.labelPosition = .bottom

        self.data = chartData
        self.data?.notifyDataChanged()
        self.notifyDataSetChanged()

        self.animate(xAxisDuration: 2.0, yAxisDuration: 2.0, easingOption: .linear)

    }

}

你可以像这样使用它

   @IBOutlet weak var barChartView: BarChartView!

    let months = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]
    let unitsSold = [20.0, 4.0, 3.0, 6.0, 12.0, 16.0, 4.0, 18.0, 2.0, 4.0, 5.0, 4.0]
    self.barChartView.setChartValues(xAxisValues: months, values: unitsSold, label: "Monthly Sales")

【讨论】：