(iOS) Chart line with Charts

0.xibView.swift

//In case we had to load a view from a xib
//In case we had a nib for the chart
   override public func awakeAfter(using aDecoder: NSCoder) -> Any? {

       let isPlaceHolder:Bool = self.subviews.count == 0

       if isPlaceHolder {
           let lineChartView:MyLineChartView? = Bundle.main.loadNibNamed("LineChartViewNibName", owner: nil, options: nil)?.first as? MyLineChartView
           lineChartView?.autoresizingMask = self.autoresizingMask;
           lineChartView?.translatesAutoresizingMaskIntoConstraints = self.translatesAutoresizingMaskIntoConstraints;
           lineChartView?.lines = self.lines
           return lineChartView
       }
       return self;

1. MyChartLineModel.swift

import UIKit

public class MyChartLineModel {

    var yValues:[Double]?
    var xValues:[Double]?
    var lineColor:UIColor?
}

2. MyLineChartView.swift

import UIKit
import Charts

public protocol MyLineChartViewDelegate : class {
    
    //Graph tapped
    func lineTapped(position:CGPoint, value:(x:Double, y:Double))
}

public class MyLineChartView: LineChartView, ChartViewDelegate {
    
    /// The line width
    private let lineWidth:CGFloat = 3.0
    
    /// Array of data models for the chart lines
    public var lines:[MyChartLineModel]?
    
    /// Show x values of the line
    public var showXValues:Bool = false
    
    /// Values formatter for the X axis
    public var xAxisLabelFormatter:IAxisValueFormatter?
    
    /// The Chart View delegate
    public weak var lineDelegate:MyLineChartViewDelegate?
    
    var viewLoaded:Bool = false
    
    //MARK: - Graph data
    
    private func createLineChartData(lineModel:MyChartLineModel) -> LineChartDataSet? {
        
        let line:LineChartDataSet? = self.createLineChartWithValues(xValues: lineModel.xValues, yValues: lineModel.yValues)
        
        //Add color
        if let lineColor = lineModel.lineColor {
            line?.colors = [lineColor] as [NSUIColor]
        }
        return line
    }
    
    private func createLineChartWithValues(xValues:[Double]?, yValues:[Double]?) -> LineChartDataSet? {
        
        //Values must not be nil and x,y values must be have the same count
        guard let xValues = xValues,
            let yValues = yValues,
            xValues.count == yValues.count else {
                return nil
        }
        
        var lineChartEntry = [ChartDataEntry]()
        
        for i in 0..<yValues.count {
            let dataEntry = ChartDataEntry(x: xValues[i], y: yValues[i])
            lineChartEntry += [dataEntry]
        }
        
        let line = LineChartDataSet(values: lineChartEntry, label: "")
        //Remove dots
        line.drawCirclesEnabled = false
        line.lineWidth = self.lineWidth
        line.mode = .cubicBezier
        line.drawValuesEnabled = false
        return line
    }
    
    //MARK: - Graph UI
    
    private func setUpGrid() -> Void {
        
        self.drawGridBackgroundEnabled = false
        self.clipValuesToContentEnabled = true
        
        self.dragEnabled = false
        self.pinchZoomEnabled = false
        self.setScaleEnabled(false)
        
        self.leftAxis.enabled = false
        self.rightAxis.enabled = false
        
        //Remove labels
        self.xAxis.drawGridLinesEnabled = true
        self.xAxis.drawAxisLineEnabled = false
        self.xAxis.drawLabelsEnabled = self.showXValues
        
        //X axis at bottom
        self.xAxis.labelPosition = XAxis.LabelPosition.bottom
        
        self.leftAxis.drawGridLinesEnabled = false
        self.leftAxis.drawAxisLineEnabled = false
        self.leftAxis.drawLabelsEnabled = false
        
        self.legend.enabled = false
    }
    
    //MARK: - Layout subviews
    
    override public func layoutSubviews() {
        super.layoutSubviews()
        
        if let _ = self.superview,
            !self.viewLoaded {
            
            self.viewLoaded = true
            self.delegate = self
            self.layoutLines()
        }
    }
    
    private func layoutLines() -> Void {
        
        //Reset data
        self.data = nil
        
        //Set up UI
        self.setUpGrid()
        
        guard let lines = self.lines else {
            self.noDataText = NSLocalizedString("No data", comment: "")
            return
        }
        
        //Add all lines
        let data = LineChartData()
        for line in lines {
            let lineSet:LineChartDataSet? = self.createLineChartData(lineModel: line)
            data.addDataSet(lineSet)
        }
        
        self.data = data
        self.highlightValue(nil)
        self.chartDescription?.text = ""
        
        if let xAxisFormatter = self.xAxisLabelFormatter {
            self.xAxis.valueFormatter = xAxisFormatter
        }
        
//        self.animate(xAxisDuration: 1.0, yAxisDuration: 0.0, easingOption: .easeInCubic)
    }
    
    //MARK: - Reload graph
    
    func reloadGraph() -> Void {
        
        self.viewLoaded = false
        self.setNeedsLayout()
        self.layoutIfNeeded()
    }
    
    //MARK: - Chart View Delegate
    
    public func chartValueSelected(_ chartView: ChartViewBase, entry: ChartDataEntry, highlight: Highlight) {
        
        self.lineDelegate?.lineTapped(position: CGPoint(x: highlight.xPx, y: highlight.yPx), value:(highlight.x, highlight.y))
    }
}

3.MyChartLineValueFormatter.swift

import UIKit
import Charts

class MyChartLineValueFormatter: NSObject, IAxisValueFormatter {
    func stringForValue(_ value: Double, axis: AxisBase?) -> String {
        
        //Return whatever value you want for x
        return "test"
    }
}

    let lineModel1:MyChartLineModel = MyChartLineModel()
    lineModel1.xValues = [1,2,3,4,5]
    lineModel1.yValues = [0.1,0.5,1.4,1.0,1.4]
    lineModel1.lineColor = UIColor.blue
    
    self.lineChartView.showXValues = true
    self.lineChartView.xAxisLabelFormatter = MyChartLineValueFormatter()  //format x axis values

    //More lines if necessary
    self.lineChartView.lines = [lineModel1]