UIViewRepresentable wont update my ios chart dataset - ios

Question

I am trying to my data derived from an API into a line chart but I can't seem to get it to work. I am storing the data in an observable object so it takes a few seconds to get it so it won't show up on my graph but when I hardcode data it works I am certain that I am getting the data but it simply won't show up. thanks
struct HomeView: View {
#State var tabIndex:Int = 0
#ObservedObject var homeViewModel = HomeViewModel()
init() {
homeViewModel.getTimelineBy("US")
}
var body: some View {
VStack(alignment: .center) {
TimelineChartView(timelineDataSet: self.$homeViewModel.countryTimeline)
}.frame(height: 500.0)
}
}
struct TimelineChartView: UIViewRepresentable {
#Binding var timelineDataSet: [ChartDataEntry]
func updateUIView(_ uiView: LineChartView, context: UIViewRepresentableContext<TimelineChartView>) {
}
var lineChart = LineChartView()
func makeUIView(context: UIViewRepresentableContext<TimelineChartView>) -> LineChartView {
setUpChart()
return lineChart
}
func setUpChart() {
lineChart.noDataText = "No Data Available"
lineChart.rightAxis.enabled = false
lineChart.backgroundColor = .white
let dataSets = [getLineChartDataSet()]
let yAxis = lineChart.leftAxis
yAxis.labelFont = .boldSystemFont(ofSize: 13)
yAxis.setLabelCount(5, force: false)
yAxis.labelTextColor = .black
yAxis.axisLineColor = .black
yAxis.labelPosition = .outsideChart
lineChart.xAxis.labelPosition = .bottom
lineChart.xAxis.labelFont = .boldSystemFont(ofSize: 13)
lineChart.xAxis.labelTextColor = .black
lineChart.xAxis.axisLineColor = .systemBlue
lineChart.animate(xAxisDuration: 2.5)
lineChart.notifyDataSetChanged()
let data = LineChartData(dataSets: dataSets)
data.setValueFont(.systemFont(ofSize: 7, weight: .black))
lineChart.data = data
}
func getChartDataPoints(selectedTimelineData: [ChartDataEntry]) -> [ChartDataEntry] {
var dataPoints: [ChartDataEntry] = []
for eachTimeline in selectedTimelineData {
let entry = ChartDataEntry(x: eachTimeline.x, y: eachTimeline.y)
dataPoints.append(entry)
}
return dataPoints
}
func getLineChartDataSet() -> LineChartDataSet {
let test = getChartDataPoints(selectedTimelineData: timelineDataSet)
let set = LineChartDataSet(entries: test, label: "DataSet")
set.lineWidth = 4
set.drawCirclesEnabled = false
set.mode = .cubicBezier
set.fillAlpha = 0.9
set.drawFilledEnabled = true
set.highlightColor = .systemRed
return set
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
HomeView()
}
}

Answer 1

Let me share some of my codes working. When the binding object is changed the chart will show the data changed.
struct HomeView: View {
#State var barData: [String: Double] = [String: Double]()
var body: some View {
NavigationView {
List {
CustomeView([BarChartVM(arg: self.$barData, title: "BarChart")])
}
}
}
}
struct CustomeView<Page:View>: View {
var viewControllers: [UIHostingController<Page>]
init(_ views: [Page]) {
self.viewControllers = views.map { UIHostingController(rootView: $0) }
}
var body: some View {
CustomeViewController(controllers: viewControllers)
}
}
struct CustomeViewController: UIViewControllerRepresentable {
var controllers: [UIViewController]
func makeUIViewController(context: Context) -> UIPageViewController {
let pageViewController = UIPageViewController(
transitionStyle: .scroll,
navigationOrientation: .horizontal)
return pageViewController
}
func updateUIViewController(_ pageViewController: UIPageViewController, context: Context) {
pageViewController.setViewControllers(
[controllers[0]], direction: .forward, animated: true)
}
}
struct BarChartVM: UIViewRepresentable {
#Binding var arg: [String: Double]
var title: String = ""
let chart = BarChartView()
func makeUIView(context: UIViewRepresentableContext<BarChartVM>) -> BarChartView {
setUpChart()
return chart
}
func updateUIView(_ uiView: BarChartView, context: UIViewRepresentableContext<BarChartVM>) {
updateChartData()
}
func setUpChart() {
chart.noDataText = "No data available"
let pointArray = arg.sorted(by: <).map { $0.key }
}
func updateChartData() {
var entries = [BarChartDataEntry]()
let valueArray = arg.sorted(by: <).map { $1 }
for i in 0..<valueArray.count {
let entry = BarChartDataEntry(x: Double(i), yValues: [valueArray[i]])
entries.append( entry)
}
let set = BarChartDataSet(entries: entries, label: title)
set.colors = ChartColorTemplates.material()
let data = BarChartData(dataSet: set)
chart.data = data
}
}