Pie chart using Charts library with iOS swift 3

Question

I want to use piechart danielgindi/Charts library on Github. My codes like this:

import UIKit
import Charts

class ChartViewController: UIViewController {

    @IBOutlet weak var pieChartView: PieChartView!

    override func viewDidLoad() {
        super.viewDidLoad()

    // Do any additional setup after loading the view.

        let months = ["Jan", "Feb", "Mar", "Apr", "May", "Jun"]
        let unitsSold = [20.0, 4.0, 6.0, 3.0, 12.0, 16.0]

        setChart(dataPoints: months, values: unitsSold)

    }


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

        var dataEntries: [ChartDataEntry] = []

        for i in 0..<dataPoints.count {
            let dataEntry1 = PieChartDataEntry(value: Double(i), label: dataPoints[i], data:  dataPoints[i] as AnyObject)
            dataEntries.append(dataEntry1)
        }

        let pieChartDataSet = PieChartDataSet(values: dataEntries, label: "Units Sold")
        let pieChartData = PieChartData(dataSet: pieChartDataSet)
        pieChartView.data = pieChartData

        var colors: [UIColor] = []

        for _ in 0..<dataPoints.count {
            let red = Double(arc4random_uniform(256))
            let green = Double(arc4random_uniform(256))
            let blue = Double(arc4random_uniform(256))

            let color = UIColor(red: CGFloat(red/255), green: CGFloat(green/255), blue: CGFloat(blue/255), alpha: 1)
            colors.append(color)
        }

        pieChartDataSet.colors = colors
    }
}

But when I run it, break down this line:

pieChartView.data = pieChartData

I dont use before any chart libraries, however I have to use one project. This library or another library doesn't matter for me. If you know answer my problem please help to me for solve. Or you can advise to me another library compatible with switf 3. Thank you.

Answer 1

I initialized pieChartView programatically and added it to subview. The code runs fine and doesn't crash. I made the necessary changes and added it below:

import UIKit
import Charts

class ChartViewController: UIViewController {

   var pieChartView: PieChartView!

   override func viewDidLoad() {
       super.viewDidLoad()

       // Do any additional setup after loading the view.

       let months = ["Jan", "Feb", "Mar", "Apr", "May", "Jun"]
       let unitsSold = [20.0, 4.0, 6.0, 3.0, 12.0, 16.0]

       pieChartView = PieChartView(frame: self.view.bounds)
       self.view.addSubview(pieChartView!)
       setChart(dataPoints: months, values: unitsSold)
   }

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

       var dataEntries: [ChartDataEntry] = []

       for i in 0..<dataPoints.count {
           let dataEntry1 = PieChartDataEntry(value: values[i], label: dataPoints[i])
           dataEntries.append(dataEntry1)
       }

       let pieChartDataSet = PieChartDataSet(values: dataEntries, label: "Units Sold")
       let pieChartData = PieChartData(dataSet: pieChartDataSet)
       pieChartView.data = pieChartData

       var colors: [UIColor] = []

       for _ in 0..<dataPoints.count {
           let red = Double(arc4random_uniform(256))
           let green = Double(arc4random_uniform(256))
           let blue = Double(arc4random_uniform(256))

           let color = UIColor(red: CGFloat(red/255), green: CGFloat(green/255), blue: CGFloat(blue/255), alpha: 1)
           colors.append(color)
       }

       pieChartDataSet.colors = colors
   }
}