MPAndroidChart折线图只显示数组的第一个label

Question

I have a line chart with data and after I calculate the labels and give to the chart, it doesn't show all of them, only the first one.

This happens on both axes.

I can't seem to find the problem. Am I missing something on the chart setUp, or in the data population.

Here how I set the chart up:

fun LineChart.init() {
    this.apply {
        ... //other non relevant set up
        with(xAxis) {
            isEnabled = true
            setDrawAxisLine(true)
            axisLineWidth = 0f
            setDrawGridLines(true)
            setDrawLabels(true)
            axisMaximum = Constants.CHART_LABELS_COUNT * 4F
            axisMinimum = 0F
            position = XAxis.XAxisPosition.BOTTOM
            granularity = Constants.CHART_LABELS_COUNT.toFloat()
            isGranularityEnabled = true
            enableGridDashedLine(10f, 10f, 10f)
        }
        axisRight.isEnabled = false
    }
}

Here is how I populate the chart with data:

with(binding.speedChart) {
    marker = CustomMarkerView(requireContext(), R.layout.custom_marker_view, 0f)
    data = lineData
    animateXY(500, 1000)

    with(axisLeft) {
        setPosition(YAxis.YAxisLabelPosition.OUTSIDE_CHART)
        axisMaximum = (((maxSpeed / CHART_LABELS_COUNT).toInt() + 1) * CHART_LABELS_COUNT).toFloat()
        axisMinimum = 0F
        granularity = CHART_LABELS_COUNT.toFloat()
        isGranularityEnabled = true
        setDrawGridLines(false)
        isEnabled = true

        setLabelCount(CHART_LABELS_COUNT - 1, true)
        valueFormatter = IndexAxisValueFormatter(yLabels)
    }
    xAxis.labelCount = CHART_LABELS_COUNT - 1
    xAxis.valueFormatter = IndexAxisValueFormatter(xLabels)
    invalidate()
}

The chart looks like this:

As you can see, and I checked with debug, the labels are calculated fine, ex. time intervals [3:01, 6:02, 9:03, 12:04, 13:05], but only the first one shows up

Answer 1

Even though I still don't understand why does this happen, what I did to make a roundabout fix is by implementing a custom ValueFormatter and the labels now are showing. I have no idea why it doesn't work with the IndexAxisValueFormatter . So, for anyone wondering, try to implement the custom ValueFormatter and override its method to get the label depending on value.