如何在iOS-charts中添加X轴上的字符串？
如何在iOS-charts中添加X轴上的字符串？
提问于 2016-08-20 08:00:09
在新版本中，我在创建一些图形时遇到了一些麻烦，之前的代码是：
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
}您可以使用下面的代码行来传递这些值，例如一个月份数组：
let chartData = BarChartData(xVals: months, dataSet: chartDataSet)在新版本之后，实现相同图形的代码是：
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
}我试了几个小时，但是我找不到修改X轴值的方法，我希望有人能帮助我，谢谢！
回答 5
Stack Overflow用户
回答已采纳
发布于 2016-08-25 23:21:25
我找到了解决方案，也许另一个可以更好地解决这个问题，而不需要创建一个新的类，这就是我发现的：
首先您需要创建一个新类，它将是您的格式化器类并添加IAxisValueFormater接口，然后您使用stringForValue方法来自定义新值，它有两个参数，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，在文件中setChart()函数的开头，您必须创建两个变量，一个用于格式化器类，另一个用于axis类：
let formato:BarChartFormatter = BarChartFormatter()
let xaxis:XAxis = XAxis()接下来，继续执行for in循环的末尾，并将索引和轴传递给格式化程序变量：
formato.stringForValue(Double(i), axis: xaxis)在循环之后，将格式添加到您的轴变量：
xaxis.valueFormatter = formato最后一步是将新的final格式添加到barChartView：
barChartView.xAxis.valueFormatter = xaxis.valueFormatter这就是setChart()函数中的所有其他行，只要保持它的位置就可以了，希望它能对您有所帮助。
Stack Overflow用户
发布于 2017-01-20 19:31:56
您好，最近我遇到了同样的问题，并以这种方式解决了它-
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
}
}在最后，只需添加委托的扩展
extension ViewController: IAxisValueFormatter {
func stringForValue(_ value: Double, axis: AxisBase?) -> String {
return months[Int(value)]
}
}通过这个链接https://medium.com/@skoli/using-realm-and-charts-with-swift-3-in-ios-10-40c42e3838c0#.minfe6kuk找到了这个解决方案
Stack Overflow用户
发布于 2017-02-24 08:33:42
正如许多人所说的，你可以创建一个类或者用IAxisValueFormatter类型扩展，但是你可以很容易地使用下面的方法，它只需要3行代码：
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
}entry是我创建的一个结构：
struct entry {
var timestamp: Int
var temperature: Double
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/39049188
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