iOS Chart library why my Bar/PieChart function has only "dataset" but no "xVals"

Question

I am using Daniel's IOS Chart framework and Xcode7.3.1. I went through basic tutorial and tried to set up first example.

Problem is I cannot assign X-axis string label

I see in tutorial when we assign data to chart, we should use

let chartData = BarChartData(xVals: dataPoints, dataSet: chartDataSet)

to complete last step, but below is what I am seeing here.

There is no parameter as "xVals" but only "dataset" is available.

Does anybody have idea?

The result would be just barchart without any xaxis label as below

Answer 1

Ok so here is example function for line chart:

  func setLineChart(dataPoints: [Double], chartInfo: String, chartDescription: String) {

    let formatter:ChartFormatter = ChartFormatter()
    let xaxis:XAxis = XAxis()

    var dataEntries: [ChartDataEntry] = Array()

    for i in 0..<dataPoints.count {
        let dataEntry = ChartDataEntry(x: Double(i), y: dataPoints[i])
        dataEntries.append(dataEntry)
        formatter.stringForValue(Double(i), axis: xaxis)
    }

    let lineChartDataSet = LineChartDataSet(values: dataEntries, label: chartInfo)
    let lineChartData = LineChartData(dataSet: lineChartDataSet)

    xaxis.valueFormatter = formatter
    lineChartView.xAxis.valueFormatter = xaxis.valueFormatter

    lineChartDataSet.mode = .CubicBezier
    lineChartDataSet.drawCirclesEnabled = false

    lineChartView.descriptionText = chartDescription
    lineChartView.data = lineChartData
    }

Here is formatter:

    @objc(ChartFormatter)
    public class ChartFormatter: NSObject, IAxisValueFormatter{

       var days: [String] = ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"]

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

And finally a call of function:

  override func viewDidLoad() {
    super.viewDidLoad()

       let values: [Double] = [1.0, 4.0, 1.5, 1.4, 1.3, 1.0, 3.0]
       let chartInfo = "chart info"
       let chartDescription = "chart description"

       self.setLineChart(values, chartInfo: chartInfo, chartDescription: chartDescription
}

so finally you will get something like this: