How to set x-axis labels with ios charts

I've recently started using the ios charts library and am having trouble finding information on how to manipulate the x-axis with the swift3 update.

What I want to do is label the x-axis with time values, e.g. 2:03:00, 2:03:01, 2:03:02, etc. In the tutorials I find online, this seems to be very easy; many of them use months of the year as the x-axis label.

However, in the swift3 update, charts now initializes values with x and y values, and I am not sure how to use labels in this version of the library. Does anyone know how to create labels in charts with swift3?

**Swift 5.5**

I'm having pretty good results using standard `DateFormatter()` I'm converting UNIX timestamp to format day.month

final class XAxisNameFormatter: NSObject, AxisValueFormatter {

func stringForValue( _ value: Double, axis _: AxisBase?) -> String {

let formatter = DateFormatter()
formatter.locale = Locale(identifier: "en_US_POSIX")
formatter.dateFormat = "dd.MM"

return formatter.string(from: Date(timeIntervalSince1970: value))
}

}

Usage:

self.lineChartView.xAxis.valueFormatter = XAxisNameFormater()
self.lineChartView.xAxis.granularity = 1.0

I had problems creating the class as the previous answers

> 'No type or protocol named 'IChartAxisValueFormatter'

I removed the `NSObject` inheritance and left only `IAxisValueFormatter` like here:

final class XAxisNameFormater: IAxisValueFormatter {.....

You can do this by creating your own formatter for the time. Below I mention sample code for that for your reference.

public class DateValueFormatter: NSObject, AxisValueFormatter {
private let dateFormatter = DateFormatter()

override init() {
super.init()
dateFormatter.dateFormat = "HH:mm:ss"
}

public func stringForValue(_ value: Double, axis: AxisBase?) -> String {
return dateFormatter.string(from: Date(timeIntervalSince1970: value))
}
}

To set your value just use below code.

self.yourChart.xAxis.valueFormatter = DateValueFormatter()
self.yourChart.xAxis.granularity = 1.0

I propose to use more flexible and pretty solution. You should have a formatter class like this:

final class MonthNameFormater: NSObject, IAxisValueFormatter {
func stringForValue( _ value: Double, axis _: AxisBase?) -> String {
return Calendar.current.shortMonthSymbols[Int(value)]
}
}

Set up this type to your `barChartView`:

barChartView.xAxis.valueFormatter = MonthNameFormater()
barChartView.xAxis.granularity = 1.0

As a result you will have: `Jan, Feb, ..., Dec`
In addition if you want to change presentation kind you should change shortMonthSymbols with some other: `monthSymbols, veryShortMonthSymbols, standaloneMonthSymbols`

**Proper Solution for X-Axis String labels in Swift 3+**

let months = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]
barChartView.xAxis.valueFormatter = IndexAxisValueFormatter(values:months)
barChartView.xAxis.granularity = 1

Create a class like this:

import Foundation
import Charts

@objc(BarChartFormatter)
class ChartFormatter:NSObject,IAxisValueFormatter{

var months: [String]! = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]

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

}

Set the x-Axis like this:

let xAxis=XAxis()
let chartFormmater=ChartFormatter()

for i in index{
chartFormmater.stringForValue(Double(i), axis: xAxis)
}

xAxis.valueFormatter=chartFormmater
chartView.xAxis.valueFormatter=xAxis.valueFormatter