Showing/Hiding lines with LineChart

Question

I have the following code to display lines on my chart using ChartsRealm. How can I show/hide individual lines on the chart?

let line1 = LineChartDataSet(values: lineChartEntry1, label: "CH4")
    let line2 = LineChartDataSet(values: lineChartEntry2, label: "O2")
    let line3 = LineChartDataSet(values: lineChartEntry3, label: "H2S")
    line1.colors = [NSUIColor.blue]
    line2.colors = [NSUIColor.green]
    line3.colors = [NSUIColor.red]
    let data = LineChartData()
    data.addDataSet(line1)
    data.addDataSet(line2)
    data.addDataSet(line3)
    chtChart.data = (data)

Answer 1

As such there is no methods to hide/show data set in Chart library.

But we can do it logically without refreshing page.

Please check below code for the same:

Create LineChartView Extension:

extension LineChartView {
    func setLineChartData(xValues: [String], labels: [String],dataSets:[Array<Double>],colors:[UIColor]) {

        var dataSetsArray: [LineChartDataSet] = []
        let dataSetCount = self.lineData?.dataSets.count
        if dataSetCount != nil && dataSetCount! > 0 {
            self.data = nil
        }

        for i in 0..<dataSets.count {
            let yVals = dataSets[i]
            var dataEntries: [ChartDataEntry] = []

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

            let chartDataSet = LineChartDataSet(values: dataEntries, label: labels[i])
            chartDataSet.highlightEnabled = true
            chartDataSet.drawHorizontalHighlightIndicatorEnabled = false
            chartDataSet.highlightColor = .blue
            chartDataSet.highlightLineWidth = 1
            chartDataSet.lineWidth = 2.0
            chartDataSet.mode = .horizontalBezier
            chartDataSet.drawCircleHoleEnabled = true
            chartDataSet.drawValuesEnabled = true
            chartDataSet.axisDependency = .left
            chartDataSet.circleHoleColor = colors[i]
            chartDataSet.highlightColor = colors[i]
            chartDataSet.colors = [colors[i]]
            //Add Data Set Into Sets array
            dataSetsArray.append(chartDataSet)

        }

        let chartData = LineChartData(dataSets: dataSetsArray)
        self.data = chartData

        self.animate(xAxisDuration: 1.0,easingOption: .easeInExpo)

    }

    func chartValueSelected(_ chartView: ChartViewBase, entry: ChartDataEntry, highlight: Highlight) {
    }

}

By adding one method into LineChartView extension and call it as per your requirements or user actins.

I called it from my segment change method like below :

@IBAction func segmentValueChanged(_ sender: Any) {

    switch self.lineSegment.selectedSegmentIndex {
    case 0:
        let colors = [UIColor.red,UIColor.green,UIColor.blue]
        lineChartView.setLineChartData(xValues: months,
                                       labels: ["Monthly Sales","Quarterly Sales","Yearly Sales"],
                                       dataSets: [unitsSold,unitsSold1,unitsSold2],
                                       colors: colors)
        break
    case 1:
        lineChartView.setLineChartData(xValues: months,
                                       labels: ["Monthly Sales"],
                                       dataSets: [unitsSold],
                                       colors: [UIColor.red])
        break
    case 2:
        lineChartView.setLineChartData(xValues: months,
                                       labels: ["Quarterly Sales"],
                                       dataSets: [unitsSold1],
                                       colors: [UIColor.green])
        break
    case 3:
        lineChartView.setLineChartData(xValues: months,
                                       labels: ["Yearly Sales"],
                                       dataSets: [unitsSold2],
                                       colors: [UIColor.blue])
        break

    default:
        break
    }

}

you can pass different data what you want in your dataset.

Check below screens for output reference:

My Segments are All | Monthly | Quarterly | Yearly

Hope this will helps you to achieve your requirements!