ios - 如何使用研究套件构建饼图

嗨，我是新手，我尝试使用研究套件应用程序构建饼图。

我参考此link编写了一些代码

运行我的代码时，它显示错误``类型'ViewController'不符合协议'ORK PieChartView DataSource''

请提出如何解决此问题的建议。

这是我的代码:

import UIKit
    import ResearchKit

    class ViewController: UIViewController,ORKPieChartViewDataSource {


        @IBOutlet weak var pieChartView: ORKPieChartView!
        var colors : NSArray!

        override func viewDidLoad() {
            super.viewDidLoad()

                colors = [
                UIColor(red: 217/225, green: 217/255, blue: 217/225, alpha: 1),
                UIColor(red: 142/255, green: 142/255, blue: 147/255, alpha: 1),
                UIColor(red: 244/255, green: 200/255, blue: 74/255, alpha: 1)
            ]

            // Connect the pie chart object to a data source
            pieChartView.dataSource = pieChartDataSource

            // Optional custom configuration
            pieChartView.showsTitleAboveChart = false
            pieChartView.showsPercentageLabels = true
            pieChartView.drawsClockwise = true
            pieChartView.titleColor = UIColor.purple
            pieChartView.textColor = UIColor.purple
            pieChartView.title = "Weekly"
            pieChartView.text = "Report"
            pieChartView.lineWidth = 10
            pieChartView.showsPercentageLabels = true

        }

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

        func numberOfSegmentsInPieChartView(pieChartView: ORKPieChartView ) -> Int {
            return 3
        }

        func pieChartView(_ pieChartView: ORKPieChartView, valueForSegmentAt index: Int) -> CGFloat {
            switch index {
            case 0:
                return 60.0
            case 1:
                return 25.0
            case 2:
                return 15.0
            }

            // Optional methods
            // Give a color to each segment in the pie chart.
            func pieChartView(pieChartView: ORKPieChartView, colorForSegmentAtIndex index: Int) -> UIColor {
                return colors[index]
            }

            // Give a title to each segment in the pie chart.
            func pieChartView(pieChartView: ORKPieChartView, titleForSegmentAtIndex index: Int) -> String {
                switch index {
                case 0:
                    return "Steps taken"
                case 1:
                    return "Tasks completed"
                case 2:
                    return "Surveys completed"
                default:
                    return "task \(index + 1)"
                }
            }
        }
    }

最佳答案

错误“类型'ViewController'不符合协议
“ORK PieChartView DataSource” means that you are not implemented all the required data source methods .....在这里，您在代码中编写了一个
wrong datasource method为func pieChartView(_ pieChartView: ORKPieChartView, valueForSegmentAt index: Int) -> CGFloat，将其更改
像下面一样。

func pieChartView(pieChartView: ORKPieChartView, valueForSegmentAt index: Int) -> CGFloat {
                switch index {
                case 0:
                    return 60.0
                case 1:
                    return 25.0
                case 2:
                    return 15.0
                }