Charts 3.0: How to set x-values for a line chart?

[arienmalec]

I want a line chart that represents temporal data with x labels for each timeperiod (e.g., each day), and x-y values only for collected data.

In the previous version, I did this like so:

let d = LineChartData(xVals: presenter.xLabels, dataSet: dataSet)
//...
self.data = d

This constructor no longer exists, and despite searching around, I haven't seen a clear substitute.

What's the Charts 3.0 equivalent?

[danielgindi]

You haven't searched enough... You can see the demos, or this:
#1474

[arienmalec]

This is not terribly responsive. By "searching around" I did intend to mean that I had read the migration note, and looking at the demos.

Despite this, the answer to my question is not apparent.

All of the demos have one y value per x value. The ChartDataEntry object takes only an x,y pair.

I want a graph that has more x value than y values.

This is similar to #1584 although I'm not sure I understand the workaround described (setting min/max x axis values).

[liuxuan30]

@arienmalec not very clear what's your issue. If you want to set x values, just follow line chart or Time Line Chart in ChartsDemo. I'ts enough info
An entry only took only one x and y. It's point, having more x values than y values in entry does not make sense.

[arienmalec]

@liuxuan30

As a concrete example, imagine an exercise log. On the x-axis, there are days. Y values are work performed. There are y values only for days when exercise was performed. The line graph displays the trend of exercise sessions.

This kind of time series chart is fairly common, and worked just fine in the previous version of Charts, by setting the xVals explicitly as noted above.

For comparison, I've attached an Excel graph that displays the pattern.

[liuxuan30]

With ChartsDemo I can have something like below that looks similar to yours.

You can also try Time Line Chart as well. they are two different x axis style.

[arienmalec]

Here's the solution for posterity:

Where the code was previously:

let d = LineChartData(xVals: xLabels, dataSet: dataSet)
//...
self.data = d

The Charts 3.0 version is:

let d = LineChartData(dataSet: dataSet)
self.data = d
self.xAxis.valueFormatter = XValsFormatter(xVals: xLabels)
xAxis.axisMinimum = Double(0)
xAxis.axisMaximum = Double(presenter.xLabels.count - 1)

class XValsFormatter: NSObject, IAxisValueFormatter {

    let xVals: [String]
    init(xVals: [String]) {
        self.xVals = xVals
    }

    func stringForValue(_ value: Double, axis: AxisBase?) -> String {
        return xVals[Int(value)]
    }

}