mpandroidchart 条形图，如何从 y 值知道 x 值？

Question

我的问题是如何知道或定义 y 轴或 x 轴的另一个（耦合）值。 我的代码：

  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);

所以如果有办法使用 valueY 和轴找到 Y 的真实对值。

这是我想要的一个例子

Answer 1

example of what I needed，这是最好的解决方案，没有过度编码

这是代码：

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);
                }
            });

Answer 2

根据您想要这些标签的位置，您有几个选择。如果要沿图表底部设置标签，可以使用 x 轴上的IndexAxisValueFormatter(labels)。如果要在条形顶部添加标签，可以在BarDataSet 上设置ValueFormatter。这是一个示例，它根据条形高度在下轴上设置“L”或“M”，在条形标签本身上设置“Less”或“More” - 也取决于条形高度。

设置x轴标签，相关命令为

xaxis.valueFormatter = IndexAxisValueFormatter(labels)

对于条形标签

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
    }
}

如果你想要条形上方的标签，你可以使用

barChart.setDrawValueAboveBar(true)

完整示例

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()