iosswiftswiftcharts

Swift Charts X-Axis Not Displaying?


I am using Swift Charts to create charts for an app but I cant seem to get the X-Axis labels to display.

The chart is configured as follows:

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


}

and the datasets are as follows:

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

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

The chart X-Axis currently shows nothing and I cant seem to figure out why? Any help is much appreciated.


Solution

  • You have to use IAxisValueFormatter to show the values on xAxis

    I have created Following class

    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)]
    
        }
    }
    

    Update your method like below

       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
    

    Hope it is helpful

    OR

    I have created a extension that is ready to use Just copy and paste it new swift file

    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)
    
        }
    
    }
    

    You can use it like

       @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")