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[英]MPAndroidChart:- How to reduce the distance between the x axis points in a line chart?
[英]MPAndroidChart - How to display a date only once on x axis with data points in milliseconds?
我的应用程序中有一个 LineChart。 我使用的数据点的 x 值是我使用 ValueFormatter 显示为日期的毫秒数。 这工作正常,除了我只想显示一次日期。 我尝试了以下代码,它几乎可以工作,但是它仅适用于显示的第一个日期。 任何帮助表示赞赏!
这是我的问题的一个例子:
这是我最成功的代码,我使用 kotlin:
val xAxis = chart.xAxis
xAxis.position = XAxis.XAxisPosition.BOTTOM
val dateFormatter = SimpleDateFormat("dd/MM")
var lastDate = ""
val formatter = object : ValueFormatter() {
override fun getFormattedValue(value: Float): String {
val date = dateFormatter.format(Date(value.toLong()))
if (date==lastDate){
return ""
}
lastDate = date
return date
}
}
xAxis.valueFormatter = formatter
以下是整个函数,json 是临时的,仅用于测试目的,应用程序将收到类似的 json。
private fun chart(){
val json = JSONObject("""{"payload":{"serie":{"data":
[[1564129484189,3287],[1564129933626,3287],[1564130385185,3287],[1564130834622,3280],[1564131284854,3280],[1564131736401,3280],
[1564132184652,3280],[1564132634092,3280],[1564133083925,3280],[1564133534963,3287],[1564133984117,3287],[1564134434677,3287],
[1564134883854,3280],[1564135333830,3280],[1564135785080,3280],[1564136234991,3280],[1564136685793,3280],[1564137134667,3280],
[1564137584570,3280],[1564138034367,3280],[1564138484236,3280],[1564138934104,3273],[1564139384690,3273],[1564139834549,3273],
[1564140284417,3280],[1564140734298,3280],[1564141183544,3280],[1564141634006,3273],[1564142083871,3273],[1564142533644,3273],
[1564142984818,3273],[1564143433797,3273],[1564143883681,3273],[1564144334485,3273],[1564144785207,3273],[1564145234378,3273],
[1564145685180,3280],[1564146134070,3280],[1564146584966,3280],[1564147034886,3280],[1564147484703,3280],[1564147934612,3280],
[1564148384456,3280],[1564148834343,3280],[1564149283943,3280],[1564149734825,3280],[1564150184715,3280],[1564150634494,3280],
[1564151084377,3287],[1564151534299,3287],[1564151984188,3287],[1564215691264,3287],[1564216142234,3287],[1564216591762,3287],
[1564217041687,3287],[1564217491103,3287],[1564217941061,3287],[1564218391529,3287],[1564218841469,3287],[1564219291586,3287],
[1564219741426,3287],[1564220192557,3287],[1564220641356,3287],[1564221091465,3280],[1564221541440,3280],[1564221991829,3280],
[1564222441313,3287],[1564222893010,3287],[1564223344202,3287],[1564223792494,3280],[1564224696695,3280],[1564225144701,3280],
[1564225591575,3280],[1564226047071,3280],[1564226492027,3280],[1564226951626,3280],[1564227392573,3280],[1564227841277,3280],
[1564228292385,3287],[1564228741844,3287],[1564229192885,3287],[1564229642831,3287],[1564230092311,3287],[1564230550690,3287],
[1564230993205,3287],[1564231443101,3287],[1564231892541,3287],[1564232344078,3280],[1564232793143,3280],[1564233255081,3280]]}}}""")
val payload = json.get("payload") as JSONObject
val serie = payload.get("serie") as JSONObject
val dataPoints = serie.get("data") as JSONArray
val values = arrayListOf<Entry>()
for (i in 0 until dataPoints.length()) {
val innerData = dataPoints[i] as JSONArray
values.add (Entry(
innerData[0].toString().toFloat() ,
innerData[1].toString().toFloat()
))
}
val chart = findViewById<LineChart>(R.id.graph2)
chart.setTouchEnabled(true)
chart.setPinchZoom(true)
chart.isScaleYEnabled = false
val dataSet = LineDataSet(values, "Service")
dataSet.color = ContextCompat.getColor(this, R.color.colorAccent)
dataSet.setCircleColor(ContextCompat.getColor(this, R.color.colorPrimaryDark))
dataSet.setDrawValues(false)
dataSet.lineWidth = 2f
val xAxis = chart.xAxis
xAxis.position = XAxis.XAxisPosition.BOTTOM
val dateFormatter = SimpleDateFormat("dd/MM")
var lastDate = ""
val formatter = object : ValueFormatter() {
override fun getFormattedValue(value: Float): String {
val date = dateFormatter.format(Date(value.toLong()))
if (date==lastDate){
return ""
}
lastDate = date
return date
}
}
xAxis.valueFormatter = formatter
val yAxisRight = chart.axisRight
yAxisRight.isEnabled = false
val yAxisLeft = chart.axisLeft
yAxisLeft.granularity = 1f
val desc = Description()
desc.text = "custom description"
chart.description = desc
val data = LineData(dataSet)
chart.data = data
chart.animateX(1000)
chart.invalidate()
}
我不知道在 kotlin 中,但在 java 中或对于某些想法,您可以在给定的链接中参考我的答案- MPAndroidChart 中的 DateTime 轴
我附上了使用IndexAxisValueFormatter
的代码。 还要在您的课程中声明 dev String 数组final String dev[] = new String[100];
并在下面的代码中使用它。
for (int i = 0; i < jsonArray1.length(); i++) {
JSONObject object1 = jsonArray1.getJSONObject(i);
dev[i] = object1.getString("block_time"); //for xaxis needed
XAxis bottomAxis = lineChart.getXAxis();
bottomAxis.setValueFormatter(new IndexAxisValueFormatter(dev));/*for x axis values*/
bottomAxis.setLabelCount(lineEntries.size());
bottomAxis.setPosition(XAxis.XAxisPosition.BOTTOM);
bottomAxis.setDrawLabels(true); //to hide all xaxis values
bottomAxis.setDrawGridLines(false);
bottomAxis.setDrawAxisLine(true);}
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