How can I call func stringForValue(_ value: Double, axis: AxisBase?) -> String

[sinqer]

What did you do?

I want to call "func stringForValue(_ value: Double, axis: AxisBase?) -> String"

What did you expect to happen?

func stringForValue not work, what can I do

my code is

class ReportDataViewController: ParentViewController {

@IBOutlet weak var heartRateLabel: UILabel!
@IBOutlet weak var heartRateTittle: UILabel!
@IBOutlet weak var heartRateRed: UILabel!
@IBOutlet weak var heartMonth: UILabel!
@IBOutlet weak var chartView: LineChartView!


override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view.
    chartView.delegate = self
    heartRateTittle.layer.cornerRadius = 4
    heartRateTittle.layer.borderColor = rgb(136, G: 136, B: 136).cgColor
    heartRateTittle.layer.borderWidth = 1
    
    
    
    HeartLineChart()
    
    
}

func HeartLineChart() {
    
    var dataEntries = [ChartDataEntry]()
    var entries2 = [ChartDataEntry]()
    var redentries = [ChartDataEntry]()
    var yellowentries = [ChartDataEntry]()
    var greenentries = [ChartDataEntry]()
    
    
    
    let ChartData = Realm.getAll(type: MUploadReport.self)
    let calender = Calendar.current
    let lastDay = calender.date(bySettingHour: 0, minute: 0, second: 0, of: Date())
    var firstDayMinusOneDay = calender.date(byAdding: .day, value: -7, to: lastDay!)
    firstDayMinusOneDay = calender.date(bySettingHour: 23, minute: 59, second: 59, of: firstDayMinusOneDay!)
    
    let lastDayAddOneDay = calender.date(byAdding: Calendar.Component.day, value: 1, to: lastDay!)
    
    for result in ChartData {
        
        if result.measureDate.isGreaterThanDate(firstDayMinusOneDay!)
            && result.measureDate.isLessThanDate(lastDayAddOneDay!)
            
        {
            
            var datestring: String?
            
            let measureDate = calender.date(bySettingHour: 0, minute: 0, second: 0, of: result.measureDate)
            
            let dif = calender.dateComponents([.day], from: lastDay! , to: measureDate!)
            
            let heartrate:Int = Int(result.HeartRate)
            
            datestring = SKFunc.dateToString(measureDate!, Formatter: "dd")
            
            let datefloat = (datestring! as NSString).doubleValue
            
            if heartrate > 100 && heartrate < 40 {
                
                let entry = ChartDataEntry.init(x: Double(datefloat), y: Double(heartrate))
                
                dataEntries.append(entry)
                
                let entry2 = ChartDataEntry.init(x: Double(datefloat), y: Double(heartrate))
                
                redentries.append(entry2)
                
               
                
                
            } else {
                
                let entry = ChartDataEntry.init(x: Double(datefloat), y: Double(heartrate))
                
                dataEntries.append(entry)
                }
        }
        
    }
    
    
    
    
    let chartDataSet = LineChartDataSet(values: dataEntries, label: "")
    chartDataSet.colors = [UIColor.clear]
  
    
    //目前折线图只包括1根折线
    let chartData = LineChartData(dataSets: [chartDataSet])
    chartView.data = chartData
    
    
    
    
    
    let xAxis = chartView.xAxis
    xAxis.labelPosition = .bottom
    xAxis.labelFont = .systemFont(ofSize: 12)
    xAxis.axisLineWidth = 0
    xAxis.gridLineWidth = 0
    //chartView.xAxis.labelRotationAngle = 50 //刻度文字倾斜角度
    xAxis.axisMaximum = 7.5
    xAxis.axisMinimum = 0.5
    
    
    
    
    
    func stringForValue(_ value: Double, axis: AxisBase?) -> String {
        
        var dayArray: [String] = []
        
        var today3 = Date()
        let dayint3:TimeInterval = 24*60*60
        today3 -= dayint3*7
        
        for _ in 0...6 {
            
            today3 += dayint3
            let dateFormatter = DateFormatter()
            dateFormatter.dateFormat = "dd"
            let stringTime = dateFormatter.string(from: today3)
            dayArray.append(stringTime)
            
        }
        
        let array3 = "Today"
        dayArray.append(array3)

        
        return dayArray[Int(value) % dayArray.count]
    }
    
}

}

Charts version/Branch/Commit Number:
**Xcode version:9.4
**Swift version:4.2
**Platform(s) running Charts:3.1.1
macOS version running Xcode:

Demo Project

ℹ Please link to or upload a project we can download that reproduces the issue.

[pmairoldi]

You need to create a class that implements the IAxisValueFormatter protocol and then set it to the axis's valueFormatter property.