Labels on x-axes not linked to chart data points

[achirkof]

I have an arrays for values and dates which I want to show on chart. But labels on x-axes are not linked to chart data points. They just spread thru x-axes evenly. I would like to labels on x-axes be linked to data points and positioned straight below chart point.

Here is my chart:

And my code below:

private class DateValueFormatter: NSObject, IAxisValueFormatter {
    private let dateFormatter = DateFormatter()
    
    override init() {
        super.init()
        dateFormatter.dateFormat = "dd/MM"
    }
    
    public func stringForValue(_ value: Double, axis: AxisBase?) -> String {
        return dateFormatter.string(from: Date(timeIntervalSince1970: value))
    }
}

class ProgressSection: BaseMainCell, ChartViewDelegate {
    
    let chartView: LineChartView = {
        let chart = LineChartView()
        chart.backgroundColor = Colors.colorWhite
        return chart
    }()
    
    var chartData = LineChartData()
    var chartEnties = [ChartDataEntry]()
    
    let weight: [Double] = [66, 66.3, 65.5, 69, 70.4, 71]
    let measureDates: [Double] = [1478266901, 1481204501, 1484228501, 1487943701, 1490109325, 1491572501]
    let measureDatesString: [String] = ["04/11", "08/12", "12/01", "24/02", "21/03", "07/04"]
    
    override func setupViews() {
        super.setupViews()
        
        addSubview(chartView)
        chartView.snp.makeConstraints { (make) in
            make.topMargin.equalToSuperview()
            make.width.equalToSuperview()
            make.height.equalToSuperview().multipliedBy(0.45)
        }
        
        addSubview(shadowView)
        shadowView.snp.makeConstraints { (make) in
            make.top.equalToSuperview().offset(-2)
            make.width.equalToSuperview()
            make.height.equalTo(2)
        }
        
        drawChart()
    }
    
    func drawChart() {
        let valueFormatter = NumberFormatter()
        valueFormatter.maximumFractionDigits = 1
        valueFormatter.minimumFractionDigits = 0
        
        for i in 0..<weight.count {
            let entry = ChartDataEntry(x: Double(measureDates[i]), y: Double(weight[i]))
            chartEnties.append(entry)
        }
        
        let weightDataset = LineChartDataSet(values: chartEnties, label: "вес, кг")
        
        let gradientColors = [Colors.colorGreen.withAlphaComponent(0).cgColor, Colors.colorGreen.withAlphaComponent(0.2).cgColor]
        let gradient = CGGradient(colorsSpace: nil, colors: gradientColors as CFArray, locations: nil)!
        weightDataset.setColor(Colors.colorGreen.withAlphaComponent(0.6))
        weightDataset.setCircleColor(Colors.colorGreen)
        weightDataset.fillAlpha = 1
        weightDataset.fill = Fill(linearGradient: gradient, angle: 90)
        weightDataset.drawFilledEnabled = true
        
        weightDataset.lineWidth = 3
        weightDataset.circleRadius = 4
        weightDataset.drawCircleHoleEnabled = false
        weightDataset.valueFont = UIFont(name: "OpenSans-Semibold", size: 12)!
        weightDataset.valueTextColor = Colors.colorGreen
        weightDataset.mode = .horizontalBezier
        
        chartData.addDataSet(weightDataset)
        chartData.setValueFormatter(DefaultValueFormatter(formatter: valueFormatter))
        
        chartView.delegate = self
        
        chartView.leftAxis.enabled = false
        chartView.rightAxis.enabled = false
        
        chartView.xAxis.setLabelCount(measureDates.count, force: true)
        chartView.xAxis.drawAxisLineEnabled = false
        chartView.xAxis.drawGridLinesEnabled = false
        chartView.xAxis.valueFormatter = DateValueFormatter()
        chartView.xAxis.forceLabelsEnabled = true
        
        chartView.drawBordersEnabled = false
        chartView.drawGridBackgroundEnabled = false
        chartView.xAxis.labelPosition = .bottom
        chartView.chartDescription?.font = UIFont(name: "OpenSans", size: 12)!
        chartView.chartDescription?.text = ""
        chartView.data = chartData
    }
}

Arrays measureDates and measureDatesString have equal values just in different format. I use it for investigation.

If I change my code:

for i in 0..<weight.count {
            let entry = ChartDataEntry(x: Double(measureDates[i]), y: Double(weight[i]))
            chartEnties.append(entry)
        }

and instead using date from measureDates array Double(measureDates[i]) put index to value x like let entry = ChartDataEntry(x: Double(i), y: Double(weight[i])) x-axes label will be positioned straight below data points, but of cause values be "01/01" for every point and it is not what I need.

[liuxuan30]

in your case, you have to override computeAxisValues() to force return the entries you want to into _axis.entries.