Question

我正在尝试使用@ danielgindi的Charts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，因为我想要它的一些功能。我的计划是删除我不需要的图表数据类型，然后离开LineChartData。

在进行最终更改之前，数据显示正确：

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。一旦我这样做，数据就会停止显示。

我已将代码与LineChart1ViewController代码进行比较，但未发现任何可能导致此问题的重大差异。我已经完成了关于Github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。我已经确认我的数据已正确订购（as suggested），但没有任何区别。正如我所提到的，使用CombinedChartData时，相同的数据会正确呈现。

我已经挣扎了几天而且我没有想法尝试。任何人都可以提出我还没有尝试过的任何想法吗？

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($0.date.timeIntervalSince1970 / 86400) })

        let maxEventsPerDay = groupedEvents.map { $1.max(by: { $0.oneRepMax < $1.oneRepMax }) }

        // MARK: - Fix the silly unwrapping
        sortedLiftEvents = maxEventsPerDay.sorted(by: { $0?.date.compare(($1?.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: $0)}

    }

    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看起来像这样：

  ▿ 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完全可以使用我的代码。可能你有类引用问题：

转到故事板并从＆＃34; CombinedChartView ＆＃34;更改图表视图类。到＆＃34; LineChartView ＆＃34;。

为什么我的折线图不显示其数据？

1 个答案: