如何在iOS图表的X轴上添加字符串？

在新版本中，我在创建一些图表时遇到了一些麻烦，以前的代码是：

func setChart(dataPoints: [String], values: [Double]) {
    var dataEntries: [BarChartDataEntry] = []

    for i in 0..<dataPoints.count {
        let dataEntry = BarChartDataEntry(value: values[i], xIndex: i)
        dataEntries.append(dataEntry)
    }

    let chartDataSet = BarChartDataSet(yVals: dataEntries, label: "Units Sold")
    let chartData = BarChartData(xVals: months, dataSet: chartDataSet)
    barChartView.data = chartData
}

新版本发布后，实现相同图形的代码为：

func setChart(dataPoints: [String], values: [Double]) {          
    var dataEntries: [BarChartDataEntry] = []

    for i in 0..<dataPoints.count {
        let dataEntry = BarChartDataEntry(x: Double(i+2), y:values[i], data: months )
        dataEntries.append(dataEntry)
    }

    let chartDataSet = BarChartDataSet(values: dataEntries, label: "Units Sold")

    let chartData = BarChartData()
    chartData.addDataSet(chartDataSet)
    barChartView.data = chartData
}

func集合图表（数据点：[String]，值：[Double]）{
var数据项：[BarChartDataEntry]=[]
对于0中的i.我找到了解决方案，也许另一个可以以更好的方式解决这个问题，而无需创建新类，这就是我发现的：

首先，您需要创建一个新类，它将是您的格式化程序类并添加IAXISValueFormatter接口，然后使用stringForValue方法自定义新值，它需要两个参数，第一个是实际值（您可以像索引一样看到它），第二个是值所在的轴

import UIKit
import Foundation
import Charts

@objc(BarChartFormatter)
public class BarChartFormatter: NSObject, IAxisValueFormatter
{
  var months: [String]! = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]

  public func stringForValue(value: Double, axis: AxisBase?) -> String 
  {
    return months[Int(value)]
  }   
}

现在，在setChart（）函数开头的文件中，您必须创建两个变量，一个用于格式化程序类，另一个用于axis类：

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

接下来，在for in循环的末尾继续，并将索引和轴传递给格式化程序变量：

formato.stringForValue(Double(i), axis: xaxis)

xaxis.valueFormatter = formato

循环后，将格式添加到轴变量：

formato.stringForValue(Double(i), axis: xaxis)

xaxis.valueFormatter = formato

最后一步是将新的xaxisformatted添加到barChartView：

barChartView.xAxis.valueFormatter = xaxis.valueFormatter

这就是setChart（）函数中的所有其他行，请将其保留在原来的位置，我希望它能帮助您。
如果要对图形进行子类化，则实现上述建议的更简洁的方法是在子类本身中实现IAxisValueFormatter协议

class CustomGraphView : LineChartView, ChartViewDelegate, IAxisValueFormatter {}

像这样

public func stringForValue(_ value: Double, axis: Charts.AxisBase?) -> String
{
    return "My X Axis Label Str";  // Return you label string, from an array perhaps.
}

然后在init（）中

您好，最近我遇到了同样的问题，并通过这种方式解决了它-

class ViewController: UIViewController {

    var months: [String]!
    var unitsSold = [Double]()
    weak var axisFormatDelegate: IAxisValueFormatter?

    @IBOutlet var viewForChart: BarChartView!
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        axisFormatDelegate = self
        months = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]
        unitsSold = [20.0, 4.0, 6.0, 3.0, 12.0, 16.0, 4.0, 18.0, 2.0, 4.0, 5.0, 4.0]

       // setChart(_ dataPoints:months,_ forY: unitsSold)
        setChart(dataEntryX: months, dataEntryY: unitsSold)
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    func setChart(dataEntryX forX:[String],dataEntryY forY: [Double]) {
        viewForChart.noDataText = "You need to provide data for the chart."
        var dataEntries:[BarChartDataEntry] = []
        for i in 0..<forX.count{
           // print(forX[i])
           // let dataEntry = BarChartDataEntry(x: (forX[i] as NSString).doubleValue, y: Double(unitsSold[i]))
            let dataEntry = BarChartDataEntry(x: Double(i), y: Double(forY[i]) , data: months as AnyObject?)
            print(dataEntry)
            dataEntries.append(dataEntry)
        }
        let chartDataSet = BarChartDataSet(values: dataEntries, label: "Units Sold")
        let chartData = BarChartData(dataSet: chartDataSet)
        viewForChart.data = chartData
        let xAxisValue = viewForChart.xAxis
        xAxisValue.valueFormatter = axisFormatDelegate

    }
}

通过这个链接找到了这个解决方案
正如许多人所说，您可以使用IAxisValueFormatter类型创建类或扩展，但您可以轻松使用以下方法，该方法只需3行：

self.chartView.xAxis.valueFormatter = DefaultAxisValueFormatter(block: {(index, _) in
    return xStrings[Int(index)]
})

下面是我的setChart（）函数，以防您对我的一些定制感兴趣：

func setChartView(entriesData: [entry]) {
    var chartEntries: [ChartDataEntry] = []
    var xStrings: [String] = []
    let sortedentriesData = entriesData.sorted { (s1: entry, s2: entry) -> Bool in
        return s1.timestamp < s2.timestamp
    }
    for (i, entry) in sortedentriesData.enumerated() {
        let newEntry = ChartDataEntry(x: Double(i), y: entry.temperature)
        chartEntries.append(newEntry)
        let dateFormatter = DateFormatter()
        dateFormatter.timeStyle = .medium
        dateFormatter.dateStyle = .none
        xStrings.append("\(dateFormatter.string(from: Date.init(timeIntervalSince1970: TimeInterval(entry.timestamp))))")
    }
    let set: LineChartDataSet = LineChartDataSet(values: chartEntries, label: "°C")
    set.setColor(NSUIColor.blue, alpha: CGFloat(1))
    set.circleColors = [NSUIColor.blue]
    set.circleRadius = 3
    set.mode = LineChartDataSet.Mode.cubicBezier

    let data: LineChartData = LineChartData(dataSet: set)
    self.chartView.xAxis.labelRotationAngle = -90
    self.chartView.xAxis.valueFormatter = DefaultAxisValueFormatter(block: {(index, _) in
        return xStrings[Int(index)]
    })
    self.chartView.xAxis.setLabelCount(xStrings.count, force: true)
    self.chartView.data = data
}

最简单的解决方案：

barChartView.xAxis.valueFormatter = IndexAxisValueFormatter(values: months)
barChartView.xAxis.granularity = 1

我是这样做到的,，
我有“yyyy-MM-dd HH:MM”格式的日期，我想在x轴的字符串起始处显示“HH:MM”

我用了三次曲线图，首先我在图表上设置了数据

func setDataCount() {

    var dataEntries: [ChartDataEntry] = []
    let formatter = CubicChartFormatter()
    let xaxis:XAxis = XAxis()
    if graphArray?.count ?? 0>0 {
        for i in 0..<graphArray!.count {
            let dateFormatter = DateFormatter()
            dateFormatter.dateFormat = "yyyy-MM-dd HH:mm"
            let date = dateFormatter.date(from:graphArray![i].writetime)
            let formatingDate = getFormattedDate(date: date!, format: "HH:mm")
            xDataPoints.append(formatingDate)
            formatter.setValues(values: xDataPoints)
            let dataEntry = ChartDataEntry(x: Double(i), y: Double(yVal)!, data: formatingDate)
            dataEntries.append(dataEntry)
            let set1 = LineChartDataSet(entries: dataEntries, label: "DataSet")
            let data = LineChartData(dataSet: set1)
            chartView.xAxis.valueFormatter = formatter
            chartView.data = data
        }
    }
}

我认为您可以使用axis value formatter.barChartView.xAixs.valueFormatter=“您的值格式化程序对象”：O，谢谢您，rmaddy，我正在尝试使用“barChartView.xAxis.valueFormatter”，但它需要“iAxisValueFormatter？”，这是一个接口，我是一个初学者，不知道如何使用这种类型，你能给我一些关于如何使用它的说明吗？嗨，你可以创建一个实现接口的类，然后创建一个类的对象，或者你可以用你当前的类实现接口并将自己传递给它。这类似于u实现tableview委托方法。谢谢，现在一切都很好！这很好，但是我如何将月份值传递到类中，而不是在格式化程序类中预先设置它们（因为我试图从CoreData获取这些值），只需添加一个新方法，例如“setArray”，它将一个数组作为参数，然后只需设置数组变量，在本例中为“months”，并使其与数组相等，在主类中，您可以将此方法称为“setArray”然后发送你想要的数组。修复了它。问题是x轴显示1个小数点，显示的每个小数点都被替换为日期。通过添加这行修复了它-希望能帮助其他人：barChartView.xAxis.decimals=0我能在Objective C中得到答案吗？@Wodjefer，我解决了这个问题。详细信息是.Xcode 8+，ObjectiveC、 ios Charts
V3.0.1
这非常适合我，谢谢分享。就像Charm谢谢你！这正是我想要的我必须移动让xAxisValue=viewForChart.xAxisValue.valueFormatter=AxisFormatter=AxisFormatter在viewForChart.data=chartData上面运行。。。
barChartView.xAxis.valueFormatter = IndexAxisValueFormatter(values: months)
barChartView.xAxis.granularity = 1

func setDataCount() {

    var dataEntries: [ChartDataEntry] = []
    let formatter = CubicChartFormatter()
    let xaxis:XAxis = XAxis()
    if graphArray?.count ?? 0>0 {
        for i in 0..<graphArray!.count {
            let dateFormatter = DateFormatter()
            dateFormatter.dateFormat = "yyyy-MM-dd HH:mm"
            let date = dateFormatter.date(from:graphArray![i].writetime)
            let formatingDate = getFormattedDate(date: date!, format: "HH:mm")
            xDataPoints.append(formatingDate)
            formatter.setValues(values: xDataPoints)
            let dataEntry = ChartDataEntry(x: Double(i), y: Double(yVal)!, data: formatingDate)
            dataEntries.append(dataEntry)
            let set1 = LineChartDataSet(entries: dataEntries, label: "DataSet")
            let data = LineChartData(dataSet: set1)
            chartView.xAxis.valueFormatter = formatter
            chartView.data = data
        }
    }
}

@objc(CubicChartFormatter)
public class CubicChartFormatter: NSObject, IAxisValueFormatter
{
   var names = [String]()

   public func stringForValue(_ value: Double, axis: AxisBase?) -> String
   {
      return names[Int(value)]
   }

   public func setValues(values: [String])
   {
      self.names = values
   } 
}