CODEWITHSUNDEEP
iosswiftcharts
Jerland2
Jerland2

Reputation: 1127

iOS swift Charts library: How to retrieve data item on graph selection?

I have a graph and when I touch it. It successfully highlights our graph, but I cannot seem to retrieve the specific datapoint that is being selected.

To be even more specific I am using a horizontal bar graph such that it is a segmented bar graph. This is our datatype used to create the bar graph is:

    updateGraph(list: Array<Double>) {
            let dataEntries = [BarChartDataEntry(x: 0.0, yValues: list)]

let barChartDataSet = BarChartDataSet(values: dataEntries, label: "")

    let colorValues = colorList.map( { $0.color })
    barChartDataSet.colors = colorValues//ChartColorTemplates.material()

    let labelValues = nameList.map( { $0.name })
    barChartDataSet.stackLabels = labelValues

    let barChartData = BarChartData(dataSet: barChartDataSet)
    barChartData.setValueFont(UIFont.systemFont(ofSize: 12.0))
    barChart.data = barChartData
}

Now when I select a specific part of this graph, I can successfully get chartValueSelected to fire, however it returns no useful data that can identify the specific list index being selected.

Upvotes: 1

Views: 1500

Answers (2)

Jerland2
Jerland2

Reputation: 1127

After an h our or so of reading the API docs and messing around with things it appears that the function chartValueSelected gives access to a chart highlight which you can extract the data index path out of using highlight.stackIndex.

very frustrating variable naming by charts... stackIndex is very counter intuitive, but alas solved.

Upvotes: 1

Dave Weston
Dave Weston

Reputation: 6635

I'm not familiar with this library, but from reading the source, it seems like the ChartViewDelegate.chartValueSelected method should have a parameter dataEntry: DataEntry which should refer to the selected entry. Is your chartValueSelected method being called? Can you update your question with its contents?

Upvotes: 0

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