过去几天我一直在学习使用 iOS 图表，并在处理从 API 调用的“单个”数据时成功地使用了它们。

但是我现在卡住了，因为我想从一个数组中提取多个数据。

我的目标是根据以下数组中每个 user_name 的 winning_streak 创建一个条形图:

["leagueStats": {
winningStreak =     (
            {
        id = 2;
        "user_name" = Dicky;
        "winning_streak" = 5;
    },
            {
        id = 6;
        "user_name" = G;
        "winning_streak" = 2;
    },
            {
        id = 5;
        "user_name" = Sultan;
        "winning_streak" = 0;
    }
);
}
]

这是我检索 API 的代码:

这是我需要帮助的地方 - 我需要生成某种循环吗？ 在提供的答案中，图表中出现的用户数量是预先设定的。

在我下面的当前代码中，它只挑选出数组中的第一个对象。我如何让它循环遍历数组并填充所需的变量？

   if let dict = json?["leagueStats"] as? [String:AnyObject] {

                        // WINNING STREAK

                        if let dataWinStreak = dict["winningStreak"] as? [[String : AnyObject]] {
                            let newdictWinStreak = dataWinStreak.first! // I'm guess this needs to be removed and this section re-structured?

                            let tempWinStreakNumber = newdictWinStreak ["winning_streak"] as? String
                            let tempWinStreakNewNumber = Int(tempWinStreakNumber!)
                            let doubleWinStreak = Double(tempWinStreakNewNumber!)

                            self.winStreak = doubleWinStreak
                            self.winningStreak =  ["Wins"]

                            let games = [self.winStreak]
                            self.setWinStreakChart(dataPoints: self.winningStreak, values: games)

                         }

然而，上面的代码仅从数组中的第一条记录中提取信息以供使用，5。

我希望能够生成 3 个不同的列，Dicky、G、Sultan，对应的值为 5 、2 和 0。

这是我显示条形图的代码 - 目前只显示 1 列，显示 5。

func setWinStreakChart(dataPoints: [String], values: [Double]){

    let formato:WinningStreakFormatter = WinningStreakFormatter()
    let xaxis:XAxis = XAxis()

    winningStreakBarChart.noDataText = "you need to provide some data for the chart."

    var dataEntries: [BarChartDataEntry] = Array()

    for i in 0..<dataPoints.count {
        let dataEntry = BarChartDataEntry(x: Double(i), y: values[i])
        dataEntries.append(dataEntry)
        formato.stringForValue (Double(i), axis: xaxis)
    }

    xaxis.valueFormatter = formato
    winningStreakBarChart.xAxis.valueFormatter = xaxis.valueFormatter

    let chartDataSet = BarChartDataSet(values: dataEntries, label: "Games Played")
    let chartData = BarChartData(dataSets: [chartDataSet])

    chartData.addDataSet(chartDataSet)
    winningStreakBarChart.data = chartData

    winningStreakBarChart.xAxis.granularityEnabled = true
    winningStreakBarChart.xAxis.granularity = 1.0

    self.winningStreakBarChart.xAxis.labelPosition = XAxis.LabelPosition.bottom

}

这是我的:

理想情况下，我想要的是 API 中的 user_name 标签“Win Streak”，然后是图例 Games _Played 表示 Winning Streak。在这个特定的例子中，我想要数组中的 3 个用户名的 3 列。

完成此操作后，作为次要目标，我想为 Losing Streak 添加另一个数据集，该数据集将按相同的 user_name 分组。

有人可以告诉我怎么做吗？谢谢

最佳答案

WinningStreakFormatter 类用于格式化 xAxis 标签，这里我使用了一种重用来自图表对象的数据的方法，因为 WinningStreakFormatter 对图 TableView 的引用很弱.因此，使用这种方法，我们可以让图 TableView 保留数据，而不是使用 WinningStreakFormatter

import Foundation
import Charts

class WinningStreakFormatter: NSObject, IAxisValueFormatter {

    weak var _chartView : BarChartView!

    init(chartView : BarChartView) {
        self._chartView = chartView
    }

    public func stringForValue(_ value: Double, axis: AxisBase?) -> String {
        let barChartData : IChartDataSet = (self._chartView.barData?.dataSets.first)!
        let barChartDataEntry : ChartDataEntry = barChartData.entryForIndex(Int(value))!
        return barChartDataEntry.data as! String
    }
}

引用下面的代码来准备建议的图表，在下面的代码中，chartView 基本上是 BarChartView 类型的实例变量。此外，我使用了与您的 API 中相同的数据结构，您可以简单地将 dataPoints 替换为您解析的数据结构。

    self.chartView.drawBarShadowEnabled = false
    self.chartView.drawValueAboveBarEnabled = true
    self.chartView.chartDescription?.enabled = false

    let  xAxis : XAxis = self.chartView.xAxis;
    xAxis.labelFont = UIFont(name: "HelveticaNeue-Light", size: 10.0)! 
    xAxis.labelTextColor = UIColor.black
    xAxis.drawAxisLineEnabled = false
    xAxis.drawGridLinesEnabled = true
    xAxis.granularity = 1;
    xAxis.labelPosition = .bottom
    xAxis.valueFormatter = WinningStreakFormatter(chartView: self.chartView)

    let yAxisLeft : YAxis = self.chartView.leftAxis
    yAxisLeft.axisMinimum = 0.0

    let yAxisRight : YAxis = self.chartView.rightAxis
    yAxisRight.axisMinimum = 0.0

    let l : Legend = self.chartView.legend;
    l.horizontalAlignment = Legend.HorizontalAlignment.left
    l.verticalAlignment = Legend.VerticalAlignment.bottom
    l.orientation = Legend.Orientation.horizontal
    l.drawInside = false
    l.form = Legend.Form.square
    l.formSize = 9.0
    l.font = UIFont(name: "HelveticaNeue-Light", size: 11.0)!
    l.xEntrySpace = 4.0

    //Data Structure built for each user for winning streak, you can use your parsing logic to prepare the same
    let winningStreakDM1 : [String : Any] = [
        "id" : 2,
        "user_name" : "Dicky",
        "winning_streak" : 5
    ]

    let winningStreakDM2 : [String : Any] = [
        "id" : 6,
        "user_name" : "G",
        "winning_streak" : 2
    ]

    let winningStreakDM3 : [String : Any] = [
        "id" : 5,
        "user_name" : "Sultan",
        "winning_streak" : 0
    ]


    //Array of the each user winning streak dictionary.
    let dataPoints = [winningStreakDM1, winningStreakDM2, winningStreakDM3]

    var values = [BarChartDataEntry]()

    for i in 0..<dataPoints.count {
        let xValue = Double(i)
        let yValue = Double(dataPoints[i]["winning_streak"] as! Int)

        let barChartDataEntry = BarChartDataEntry(x: xValue, y: yValue, data: dataPoints[i]["user_name"] as AnyObject)
        values.append(barChartDataEntry)
    }

    let barChartDataSet = BarChartDataSet(values: values, label: "Winning Streak")
    barChartDataSet.colors = ChartColorTemplates.material()

    let barChartData = BarChartData(dataSet: barChartDataSet)
    barChartData.setValueFont(UIFont.systemFont(ofSize: 12.0))
    self.chartView.data = barChartData

关于ios - 从数组中提取多个数据时如何使用 iOS 图表？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/41524170/