问如何用MPChart系统绘制心电图的网格线

EN

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)

    val chart = findViewById<LineChart>(R.id.chart)


    val lines = mutableListOf<LineDataSet>()

    val x = (0..100).map { i -> 0.1f*i }
    val y = x.map { i -> 5*sin(7*i)*sin(0.5f*i)* cos(3.25f*i) }

    val primaryLine = LineDataSet(x.zip(y).map { Entry(it.first, it.second) }, "primary")
    primaryLine.setDrawCircles(false)
    primaryLine.lineWidth = 3f
    primaryLine.color = Color.RED
    primaryLine.setDrawValues(false)
    primaryLine.isHighlightEnabled = false

    val majorX = 2f
    val majorY = 4f
    val minorX = majorX/5
    val minorY = majorY/5

    val xmin = floor(x.min()/majorX)*majorX
    val xmax = ceil(x.max()/majorX)*majorX
    val ymin = floor(y.min()/majorY)*majorY
    val ymax = ceil(y.max()/majorY)*majorY

    xGridLines(lines, minorX, ymin, ymax, xmin, xmax, false)
    yGridLines(lines, minorY, ymin, ymax, xmin, xmax, false)

    xGridLines(lines, majorX, ymin, ymax, xmin, xmax, true)
    yGridLines(lines, majorY, ymin, ymax, xmin, xmax, true)

    lines.add(primaryLine)

    chart.axisRight.isEnabled = false
    val yAx = chart.axisLeft
    yAx.setDrawLabels(false)
    yAx.setDrawGridLines(false)
    yAx.setDrawAxisLine(false)
    yAx.axisMinimum = ymin
    yAx.axisMaximum = ymax

    val xAx = chart.xAxis
    xAx.setDrawLabels(false)
    xAx.position = XAxis.XAxisPosition.BOTTOM
    xAx.setDrawGridLines(false)
    xAx.setDrawAxisLine(false)
    xAx.axisMinimum = xmin
    xAx.axisMaximum = xmax+0.01f

    chart.data = LineData(lines.toList())
    chart.description.isEnabled = false
    chart.legend.isEnabled = false
}

private fun yGridLines(lines: MutableList<LineDataSet>, spacing: Float, ymin: Float, ymax: Float, xmin: Float, xmax: Float, major: Boolean) {
    val nY = ((ymax-ymin)/spacing).roundToInt()
    for(i in 0..nY) {
        val yl = ymin + i*spacing
        val ep = listOf(Entry(xmin,yl), Entry(xmax,yl))
        lines.add(makeGridLineDataSet(ep, major))
    }
}

private fun xGridLines(lines: MutableList<LineDataSet>, spacing: Float, ymin: Float, ymax: Float, xmin: Float, xmax: Float, major: Boolean) {
    val nX = ((xmax-xmin)/spacing).roundToInt()
    for(i in 0..nX) {
        val xl = xmin + i*spacing
        val ep = listOf(Entry(xl, ymin), Entry(xl,ymax))
        lines.add(makeGridLineDataSet(ep, major))
    }
}

private fun makeGridLineDataSet(e: List<Entry>, major: Boolean): LineDataSet {
    val ds = LineDataSet(e,"")
    ds.setDrawCircles(false)
    if( major ) {
        ds.color = Color.BLACK
        ds.lineWidth = 1f
    }
    else {
        ds.color = Color.BLACK
        ds.lineWidth = 0.5f
        ds.enableDashedLine(10f,10f,0f)
    }
    ds.setDrawValues(false)
    ds.isHighlightEnabled = false
    return ds
}