Not matching available overloads error with ioscharts - swift

Question

I want to set up bar charts with Swift 3 and follow this tutorial.
I created a barChartView within my viewController and the data values in viewDidLoad:
var months: [String]!
var counts: [Double]!
months = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]
counts = [20.0, 4.0, 6.0, 3.0, 12.0, 16.0, 4.0, 18.0, 2.0, 4.0, 5.0, 4.0]
Then I call the setChart function with the values:
setChart(dataPoints: months, values: counts)
The function itself looks as follows:
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(values: dataEntries, label: "Units Sold")
let chartData = BarChartData(xVals: months, dataSet: chartDataSet)
countPerCountryView.data = chartData
}
I am getting two error warnings when trying to build, here:
let dataEntry = BarChartDataEntry(value: values[i], xIndex: i)
Argument labels '(value:, xindex:)' do not match any available overloads
and here:
let chartData = BarChartData(xVals: months, dataSet: chartDataSet)
Cannot invoke initializer for type 'BarChartData' with an argument list of type '(xvals: [String]!, dataSet: BarChartDataSet)'

Answer 1

iOS-Chart has had some changes:
BarChartDataEntry(value:xIndex:) was changed to BarChartDataEntry(x: y:)
BarChartData(xVals: dataSet:) was changed to BarChartData(dataSet:)
So you need something like this
func setChart(dataPoints: [String], values: [Double]) {
var dataEntries: [BarChartDataEntry] = []
for i in 0..<dataPoints.count {
let dataEntry = BarChartDataEntry(x: Double(i), y: values[i])
dataEntries.append(dataEntry)
}
let chartDataSet = BarChartDataSet(values: dataEntries, label: "Units Sold")
let chartData = BarChartData(dataSet: chartDataSet)
countPerCountryView.data = chartData
}
Also if you want to set labels for xAxis you need to implement IAxisValueFormatter protocol with method stringForValue( _: axis:)
You can do it in your ViewController, for example:
class ViewController: UIViewController, IAxisValueFormatter {
// your code ...
// implement delegate method
func stringForValue(_ dataPointIndex: Double, axis: AxisBase?) -> String {
return someDataPoints[Int(dataPointIndex)]
}
func setChart(dataPoints: [String], values: [Double]){
// your code ...
// Set delegate
lineChartView.xAxis.valueFormatter = self
}
// your code ...
}

Answer 2

Charts 3.0 has some breaking changes. Try this
class BarChartViewController: UIViewController, ChartViewDelegate {
#IBOutlet weak var barChartView: BarChartView!
let months = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
barChartView.delegate = self
barChartView.xAxis.valueFormatter = self
let 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(values: unitsSold)
}
func setChart(values: [Double]) {
barChartView.noDataText = "You need to provide data for the chart."
let chartData = BarChartDataSet()
for (i, val) in values.enumerated(){
_ = chartData.addEntry(BarChartDataEntry(x: Double(i), y: val))
}
barChartView.data = BarChartData(dataSet: chartData)
}
}
extension BarChartViewController: IAxisValueFormatter{
func stringForValue(_ value: Double, axis: AxisBase?) -> String {
return months[ Int(value) % months.count]
}
}