How to implement Charts in SwiftUI?

Question

How can I make a chart view using Charts library in SwiftUI

In other words, how to make a UIViewRepresentable for it?

Answer 1

Here is some sample code that should get you started. Not sure if this is best practice, but it was the easiest way to get me going with Charts and SwiftUI. Hope this helps!

import SwiftUI
import Charts

struct GraphSwiftUI: View {
    var body: some View {
        GeometryReader { p in
            VStack {
                LineChartSwiftUI()
                    //use frame to change the graph size within your SwiftUI view
                    .frame(width: p.size.width, height: p.size.height/5, alignment: .center)
            }
        }
    }
}

struct LineChartSwiftUI: UIViewRepresentable {
    let lineChart = LineChartView()

    func makeUIView(context: UIViewRepresentableContext<LineChartSwiftUI>) -> LineChartView {
        setUpChart()
        return lineChart
    }

    func updateUIView(_ uiView: LineChartView, context: UIViewRepresentableContext<LineChartSwiftUI>) {

    }

    func setUpChart() {
        lineChart.noDataText = "No Data Available"
        let dataSets = [getLineChartDataSet()]
        let data = LineChartData(dataSets: dataSets)
        data.setValueFont(.systemFont(ofSize: 7, weight: .light))
        lineChart.data = data
    }

    func getChartDataPoints(sessions: [Int], accuracy: [Double]) -> [ChartDataEntry] {
        var dataPoints: [ChartDataEntry] = []
        for count in (0..<sessions.count) {
            dataPoints.append(ChartDataEntry.init(x: Double(sessions[count]), y: accuracy[count]))
        }
        return dataPoints
    }

    func getLineChartDataSet() -> LineChartDataSet {
        let dataPoints = getChartDataPoints(sessions: [0,1,2], accuracy: [100.0, 20.0, 30.0])
        let set = LineChartDataSet(entries: dataPoints, label: "DataSet")
        set.lineWidth = 2.5
        set.circleRadius = 4
        set.circleHoleRadius = 2
        let color = ChartColorTemplates.vordiplom()[0]
        set.setColor(color)
        set.setCircleColor(color)
        return set
    }
}

struct GraphSwiftUI_Previews: PreviewProvider {
    static var previews: some View {
        GraphSwiftUI()
    }
}

Answer 2

You can't yet since they the maintainer does only fix builds himself after Xcode11 is released and the pullrequest is stagnating. You can always fix a local copy though or use the repo from the pull request, but that lead me to a lot of hurt when switching back to any other url (manual deletion of lines from .xcodeproj/.xcworkspace).

Answer 3

If you want to update the view of the graph every time the data changes, add a UpdateData() function where you set and return your LineChartData() object.

Then set uiView.data = UpdateData() and call uiView.notifyDataSetChanged() .
This should re-render your graph.