Issue with order of x-values and Multi LineChart

[casim]

I'm still using swift 2 so I use Charts 2.3.1
I have to load some measurement data (Waist, Weight, Hip) that the user is adding. Something like this:

To display the data correctly with an ascending date order (x-value) I have to order the xValues and also partially order the yValues as well. If I don't order the yValue as well some data are not shown or the line chart is plotted wrong.

I'm slightly confused on why do I need to to do the second step for each yVals dataset given that I already provide an ordered xVals and the correct index.

Any help would be appreciated, I'm moving torward dynamicaly load different datasets so the code would be much easier to understand if I only have to order the xVals.

[casim]

This is the code with the changes I made to fix it commented out

        typealias entry = (label: String, value: Double) 
        let labels = ["04/20","04/22", "04/23","04/24", "04/26", "05/02", "05/08", "05/15"]
        let weights:[entry] = [(label: "04/22", value: 84.5),
                               (label: "05/15", value: 85.6),
                               (label: "04/24", value: 85),
                               (label: "04/20", value: 84.2),
                               (label: "05/02", value: 86)]
        let waists:[entry] = [(label: "04/26", value: 86),
                               (label: "05/15", value: 86.5),
                               (label: "05/08", value: 86.5),
                               (label: "04/23", value: 86.2)]

        
        // 1 - creating an array of data entries
        var yVals1 : [ChartDataEntry] = [ChartDataEntry]()
        for weight in weights {
            yVals1.append(ChartDataEntry(value: weight.value, xIndex: labels.indexOf(weight.label)!))
        }
        
        // FIX: append DataEntry based on label order
        //        for label in labels {
        //            let optEntry = weights.filter {$0.label == label}.first
        //            if let entry = optEntry {
        //                   yVals1.append(ChartDataEntry(value: entry.value, xIndex: labels.indexOf(entry.label)!))
        //            }
        //            
        //        }

        let set1: LineChartDataSet = LineChartDataSet(yVals: yVals1, label: "First Set")
        set1.axisDependency = .Left // Line will correlate with left axis values
        set1.setColor(UIColor.redColor().colorWithAlphaComponent(0.5))
        set1.setCircleColor(UIColor.redColor())
        set1.lineWidth = 2.0
        set1.circleRadius = 6.0
        set1.fillAlpha = 65 / 255.0
        set1.fillColor = UIColor.redColor()
        set1.highlightColor = UIColor.whiteColor()
        set1.drawCircleHoleEnabled = true
        
        var yVals2 : [ChartDataEntry] = [ChartDataEntry]()
        for waist in waists {
            yVals2.append(ChartDataEntry(value: waist.value, xIndex: labels.indexOf(waist.label)!))
        }
        
        // FIX: append DataEntry based on label order
        //        for label in labels {
        //            let optEntry = waists.filter {$0.label == label}.first
        //            if let entry = optEntry {
        //                yVals2.append(ChartDataEntry(value: entry.value, xIndex: labels.indexOf(entry.label)!))
        //            }
        //            
        //        }

        let set2: LineChartDataSet = LineChartDataSet(yVals: yVals2, label: "Second Set")
        set2.axisDependency = .Left // Line will correlate with left axis values
        set2.setColor(UIColor.greenColor().colorWithAlphaComponent(0.5))
        set2.setCircleColor(UIColor.greenColor())
        set2.lineWidth = 2.0
        set2.circleRadius = 6.0
        set2.fillAlpha = 65 / 255.0
        set2.fillColor = UIColor.greenColor()
        set2.highlightColor = UIColor.whiteColor()
        set2.drawCircleHoleEnabled = true
        
        //3 - create an array to store our LineChartDataSets
        var dataSets : [LineChartDataSet] = [LineChartDataSet]()
        dataSets.append(set1)
        dataSets.append(set2)

        //4 - pass our months in for our x-axis label value along with our dataSets
        let data: LineChartData = LineChartData(xVals: labels, dataSets: dataSets)
        
        //5 - finally set our data
        let lineChart = LineChartView(frame: CGRect.init(x: 0, y: 50, width: 350, height: 200))
        lineChart.descriptionText = ""
        lineChart.descriptionTextColor = UIColor.blueColor()
        lineChart.drawGridBackgroundEnabled = true
        lineChart.gridBackgroundColor = UIColor.darkGrayColor()
        lineChart.noDataText = "No data provided"
        lineChart.delegate = self
        lineChart.data = data

[liuxuan30]

2.x is not maintained anymore. so you are on your own and fix any bugs you found.

[casim]

@liuxuan30 if you have any pointers on where I should start looking, it would be appriated. thanks