mpandroidchart bar chart, how to know the x value from y value?

Question

my problem is how to know or define the other(couple) value of the y-axis or x-axis. My code :

  formatterValueY = new ValueFormatter() {
            @Override
            public String getAxisLabel(float valueY, AxisBase axis) {
                //how to find the valueX of valueY ??
                // need it to return string 
                //note: I know the search solution(data loop 
               //search),
                // it is useless if there is two equal values y1=y2
      
                //this is example of what I wanna achieve,
                // this is simple example,
                
               float x = findTheRealXOfY(valueY);
               //or
               //float x = findTheRealXOfY(valueY,axis);

               if(x %2==0)
               {
                    return "Pair:"+valueY;
                 }
               else{
                  return "inPair:"+valueY;
                }

                
            }
        }


        YAxis yAxis = myBarChar.getYAxis();
        yAxis.setValueFormatter(formatterValueY);

so if there is way to find the real pair value of Y using the valueY and axis.

This is an example of what I want

Answer 1

Depending on where you want these labels you have a couple options. If you want to set the labels along the bottom of the chart, you can use the IndexAxisValueFormatter(labels) on the x axis. If you want to add labels on the top of the bars you can set a ValueFormatter on the BarDataSet. Here is an example that sets "L" or "M" on the lower axis depending on the bar height, and "Less" or "More" on the bar label itself - also depending on the bar height.

For setting the x axis labels, the relevant command is

xaxis.valueFormatter = IndexAxisValueFormatter(labels)

and for the bar labels

barDataSet.valueFormatter = object : ValueFormatter() {
    override fun getBarLabel(barEntry: BarEntry?): String {
        var label = ""
        barEntry?.let { e ->
            // here you can access both x and y
            label = if( e.y > 25 ) {
                "More"
            } else {
                "Less"
            }
        }
        return label
    }
}

If you want the labels above the bars, you can use

barChart.setDrawValueAboveBar(true)

Complete Example

val barChart = findViewById<BarChart>(R.id.bar_chart)

// the values on your bar chart - wherever they may come from
val yVals = listOf(10f, 20f, 30f, 40f, 50f, 60f)

val valueSet1 = ArrayList<BarEntry>()
val labels = ArrayList<String>()

// You can create your data sets and labels at the same time - 
// then you have access to the x and y values and can 
// determine what labels to set
for (i in yVals.indices) {
    val yVal = yVals[i]
    val entry = BarEntry(i.toFloat(), yVal)
    valueSet1.add(entry)

    if( yVal > 20) {
        labels.add("M")
    }
    else {
        labels.add("L")
    }
}

val dataSets: MutableList<IBarDataSet> = ArrayList()
val barDataSet = BarDataSet(valueSet1, " ")

barChart.setDrawBarShadow(false)
barChart.setDrawValueAboveBar(false)
barChart.description.isEnabled = false
barChart.setDrawGridBackground(false)


val xaxis: XAxis = barChart.xAxis
xaxis.setDrawGridLines(false)
xaxis.position = XAxis.XAxisPosition.BOTTOM
xaxis.granularity = 1f
xaxis.isGranularityEnabled = true
xaxis.setDrawLabels(true)
xaxis.setDrawAxisLine(false)
xaxis.valueFormatter = IndexAxisValueFormatter(labels)
xaxis.textSize = 15f

val yAxisLeft: YAxis = barChart.axisLeft
yAxisLeft.setPosition(YAxis.YAxisLabelPosition.OUTSIDE_CHART)
yAxisLeft.setDrawGridLines(true)
yAxisLeft.setDrawAxisLine(true)
yAxisLeft.isEnabled = true
yAxisLeft.textSize = 15f

barChart.axisRight.isEnabled = false
barChart.extraBottomOffset = 10f
barChart.extraLeftOffset = 10f

val legend: Legend = barChart.legend
legend.isEnabled = false


barDataSet.color = Color.CYAN
barDataSet.valueTextSize = 15f

// You can also set a value formatter on the bar data set itself (and enable
// setDrawValues). In this you get a BarEntry which has both the x position
// and bar height.
barDataSet.setDrawValues(true)
barDataSet.valueFormatter = object : ValueFormatter() {
    override fun getBarLabel(barEntry: BarEntry?): String {
        var label = ""
        barEntry?.let { e ->
            // here you can access both x and y
            // values with e.x and e.y
            label = if( e.y > 25 ) {
                "More"
            } else {
                "Less"
            }
        }
        return label
    }
}
dataSets.add(barDataSet)

val data = BarData(dataSets)
barChart.data = data
barChart.invalidate()

Answer 2

example of what I needed, this is the best solution, with no over-code

this is the code:

BarData data = new BarData(colorBarSet);

data.setValueFormatter(new ValueFormatter() {

                @Override
                public String getBarLabel(BarEntry barEntry) {
                    Log.e("TAG", "this is the X value: " + barEntry.getX());
                    Log.e("TAG", "this is the Y value: " + barEntry.getY());

                // this will return "Girl" for red color with x value=1, 
                // value of x is the index of the color in bar chart
                return getMajeureVoteOfColor(barEntry.getX);
                }
            });