为什么我的折线图不显示其数据？

Question

我正在尝试使用@danielgindi 的图表框架来创建折线图，但我的数据不会显示在图表上：

我从 CombinedChartViewController 演示开始，因为我想要它具有的一些功能。我的计划是删除我不需要的图表数据类型并保留 LineChartData.

最后修改之前，数据显示正常：

然后，我将 data 的类型从 CombinedChartData 更改为 LineChartData 并将 LineChartData 分配给 chartView.data 而不是 data.lineData .我一这样做，数据就停止显示了。

我按代码与 LineChart1ViewController 代码进行了比较，没有发现任何可能导致此问题的 material 差异。我已经仔细阅读了 Github 上的文档和问题，并查看了我可以在 SO 上找到的所有相关问题。我已确认我的数据已正确排序 ()，但没有任何区别。正如我提到的，相同的数据在使用 CombinedChartData 时可以正确呈现。

我已经为此苦苦挣扎了几天，但我没有想法可以尝试。谁能提供我尚未尝试过的任何想法？

import UIKit
import Charts

var shouldHideData: Bool = false

class ChartViewController: UIViewController, ChartViewDelegate {

    @IBOutlet var chartView: LineChartView!

    fileprivate let dataManager = CoreDataHelper()

    fileprivate var sortedLiftEvents: [LiftEvent] = []

    var days: [String]? = []

    override func viewDidLoad() {
        super.viewDidLoad()

        self.title = "1RM"

        chartView.delegate = self
        chartView.chartDescription?.enabled = false

        let leftAxis = chartView.leftAxis
        leftAxis.axisMinimum = 0
        leftAxis.labelTextColor = NSUIColor.white

        let xAxis = chartView.xAxis
        xAxis.labelPosition = .bottom
        xAxis.axisMinimum = 0
        xAxis.granularity = 1
        xAxis.valueFormatter = self
        xAxis.labelTextColor = NSUIColor.white

        chartView.rightAxis.enabled = false // this fixed the extra xAxis grid lines

        chartView.backgroundColor = NSUIColor(red: 35/255.0, green: 43/255.0, blue: 53/255.0, alpha: 1.0)

        fetchData()

        self.updateChartData()

        chartView.configureDefaults()

        chartView.setVisibleXRangeMaximum(5)

        view.backgroundColor = UIColor(hexString: "232B35")
    }

    private func fetchData() {

        let liftEventTypeUuid = "98608870-E3CE-476A-B1E4-018D2AE4BDBF"

        // get all Bench Press events
        let liftEvents = dataManager.fetchLiftsEventsOfType(liftEventTypeUuid)

        // put them into a Dictionary grouped by each unique day
        let groupedEvents = Dictionary(grouping: liftEvents, by: { floor([=10=].date.timeIntervalSince1970 / 86400) })

        let maxEventsPerDay = groupedEvents.map { .max(by: { [=10=].oneRepMax < .oneRepMax }) }

        // MARK: - Fix the silly unwrapping
        sortedLiftEvents = maxEventsPerDay.sorted(by: { [=10=]?.date.compare((?.date)!) == .orderedAscending }) as! [LiftEvent]

        /// 3600 = 1 hour
        /// 1 day
        let startingDate = sortedLiftEvents.first?.date
        let endDate = sortedLiftEvents.last?.date
        let intervalBetweenDates:TimeInterval = 3600 * 24

        let dates:[Date] = intervalDates(from: startingDate!, to: endDate!, with: intervalBetweenDates)

        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = "MMM d"

        days = dates.map{dateFormatter.string(from: [=10=])}

    }

    func updateChartData() {
        if shouldHideData {
            chartView.data = nil
            return
        }

       self.setChartData()

    }

    func setChartData() {

        generateLineData()

    }

    func generateLineData() {
        let entries = sortedLiftEvents.enumerated().map { (arg) -> ChartDataEntry in
            let (index, liftEvent) = arg
            return ChartDataEntry(x: Double(index), y: liftEvent.oneRepMax.value)
        }

        // style the line to be drawn
        let set = LineChartDataSet(values: entries, label: "Line DataSet")
        set.setColor(UIColor(hexString: "768DAA"))
        set.lineWidth = 1.5
        set.setCircleColor((UIColor(hexString: "768DAA")))
        set.circleHoleColor = UIColor(red: 35/255, green: 43/255, blue: 53/255, alpha: 1)
        set.circleRadius = 4
        set.circleHoleRadius = 2
        // set.fillColor = (UIColor(hexString: "F20B27"))
        set.mode = .linear
        set.drawValuesEnabled = true
        set.valueFont = .systemFont(ofSize: 10)
        set.valueTextColor = UIColor(red: 240/255, green: 238/255, blue: 70/255, alpha: 1)

        set.axisDependency = .left

        let data = LineChartData(dataSet: set)

        chartView.data = data
    }

    func intervalDates(from startingDate:Date, to endDate:Date, with interval:TimeInterval) -> [Date] {
        guard interval > 0 else { return [] }

        var dates:[Date] = []
        var currentDate = startingDate

        while currentDate <= endDate {
            currentDate = currentDate.addingTimeInterval(interval)
            dates.append(currentDate)
        }

        return dates
    }
}

extension ChartViewController: IAxisValueFormatter {
    func stringForValue(_ value: Double, axis: AxisBase?) -> String {
        guard let days = days else { return "" }

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

entries 中的 ChartDataEntry 如下所示：

  ▿ 0 : ChartDataEntry, x: 0.0, y 209.0
  ▿ 1 : ChartDataEntry, x: 1.0, y 209.0
  ▿ 2 : ChartDataEntry, x: 2.0, y 246.0
  ▿ 3 : ChartDataEntry, x: 3.0, y 233.333333333333
  ▿ 4 : ChartDataEntry, x: 4.0, y 220.0
  ▿ 5 : ChartDataEntry, x: 5.0, y 234.0
  ▿ 6 : ChartDataEntry, x: 6.0, y 220.0
  ▿ 7 : ChartDataEntry, x: 7.0, y 240.0
  ▿ 8 : ChartDataEntry, x: 8.0, y 227.5
  ▿ 9 : ChartDataEntry, x: 9.0, y 239.166666666667
  ▿ 10 : ChartDataEntry, x: 10.0, y 234.666666666667

... 

  ▿ 90 : ChartDataEntry, x: 90.0, y 220.0
  ▿ 91 : ChartDataEntry, x: 91.0, y 238.0
  ▿ 92 : ChartDataEntry, x: 92.0, y 234.0
  ▿ 93 : ChartDataEntry, x: 93.0, y 220.0
  ▿ 94 : ChartDataEntry, x: 94.0, y 240.0
  ▿ 95 : ChartDataEntry, x: 95.0, y 226.666666666667
  ▿ 96 : ChartDataEntry, x: 96.0, y 227.5
  ▿ 97 : ChartDataEntry, x: 97.0, y 239.166666666667
  ▿ 98 : ChartDataEntry, x: 98.0, y 234.666666666667
  ▿ 99 : ChartDataEntry, x: 99.0, y 240.0
  ▿ 100 : ChartDataEntry, x: 100.0, y 222.0

Answer 1

您的视图控制器代码与我的代码完全一致。可能你有一个 class 引用问题：

转到 Storyboard 并将图表视图 class 从“CombinedChartView”更改为“LineChartView”。

为什么我的折线图不显示其数据？

Why doesn't my line chart display its data?

swift

ios-charts