使用 https://github.com/PhilJay/MPAndroidChart 绘制基金净值变化曲线

0_MPAndroidChart 绘制多组线状图.md

1_SubjectNetWorthChartResp.java

public class SubjectNetWorthChartResp {
    public String label1;
    public String label2;
    public String label3;
    public int xSkipCount;
    public List<String> xSet = new ArrayList<>();
    public List<Float> ySet1 = new ArrayList<>();
    public List<Float> ySet2 = new ArrayList<>();
    public List<Float> ySet3 = new ArrayList<>();
}

2_MockResp.java

public Call<SubjectNetWorthChartResp> getSubjectNetWorthChart(@Path("id") int subjectId) {
  SubjectNetWorthChartResp resp = new SubjectNetWorthChartResp();
  resp.label1 = "南方宝元";
  resp.label2 = "沪深300";
  resp.label3 = "同类平均";
  resp.xSkipCount = 6;
  Calendar rightNow = Calendar.getInstance();
  Calendar startDate = Calendar.getInstance();
  startDate.add(Calendar.MONTH, -1);

  // 返回上月同日至今的图标数据
  float max = 9.0f;
  float min = -3.0f;
  Random random = new Random();
  for (Date date = startDate.getTime(); startDate.before(rightNow); startDate.add(Calendar.DATE, 1)) {
      String strDate = new SimpleDateFormat("MM-dd").format(startDate.getTime());
      resp.xSet.add(strDate);
      // http://stackoverflow.com/questions/6078157/random-nextfloat-is-not-applicable-for-floats
      resp.ySet1.add(random.nextFloat() * (max - min) + min);
      resp.ySet2.add(random.nextFloat() * (max - min) + min);
      resp.ySet3.add(random.nextFloat() * (max - min) + min);
  }

  return resp;
}

3_View.java

protected void getChartDataCallback(SubjectNetWorthChartResp resp) {

  ArrayList<ILineDataSet> lineDateSets = getDataSet(resp);
  LineData lineData = new LineData(resp.xSet, lineDateSets);
  chart.setData(lineData);

  XAxis xAxis = chart.getXAxis();
  xAxis.setPosition(XAxis.XAxisPosition.BOTTOM);
  xAxis.setLabelsToSkip(resp.xSkipCount);
  xAxis.enableGridDashedLine(5f, 5f, 0);

  YAxis axisLeft = chart.getAxisLeft();
  // 处理Y轴坐标文字格式为 0.00%
  axisLeft.setValueFormatter(new MyPercentFormatter());
  axisLeft.setPosition(YAxis.YAxisLabelPosition.INSIDE_CHART);
  axisLeft.enableGridDashedLine(5f, 5f, 0);
  axisLeft.setDrawZeroLine(false);

  YAxis axisRight = chart.getAxisRight();
  axisRight.setDrawLabels(false);
  axisRight.setDrawGridLines(false);
  axisRight.setDrawZeroLine(false);

  // 自定义YAxisRenderer，为了满足正负值坐标文字不同颜色的需求
  MyYAxisRenderer myYAxisRenderer = new MyYAxisRenderer(chart.getViewPortHandler(), axisLeft, chart.getTransformer(YAxis.AxisDependency.LEFT));
  chart.setRendererLeftYAxis(myYAxisRenderer);

  Legend legend = chart.getLegend();
  legend.setPosition(Legend.LegendPosition.BELOW_CHART_RIGHT);


  chart.setDescription("");
  chart.setNoDataText("暂无数据");

  chart.invalidate();
}

private ArrayList<ILineDataSet> getDataSet(SubjectNetWorthChartResp resp) {
  ArrayList<ILineDataSet> dataSets = null;

  ArrayList<Entry> valueSet1 = new ArrayList<>();
  ArrayList<Entry> valueSet2 = new ArrayList<>();
  ArrayList<Entry> valueSet3 = new ArrayList<>();
  Entry entry;

  for (int i = 0; i < resp.ySet1.size(); i++) {
      entry = new Entry(resp.ySet1.get(i), i);
      valueSet1.add(entry);
  }

  for (int i = 0; i < resp.ySet2.size(); i++) {
      entry = new Entry(resp.ySet2.get(i), i);
      valueSet2.add(entry);
  }

  for (int i = 0; i < resp.ySet3.size(); i++) {
      entry = new Entry(resp.ySet3.get(i), i);
      valueSet3.add(entry);
  }

  LineDataSet lineDataSet1 = new LineDataSet(valueSet1, resp.label1);
  lineDataSet1.setColor(Color.parseColor("#FE3651"));
  lineDataSet1.setDrawValues(false);
  lineDataSet1.setDrawCircleHole(false);
  lineDataSet1.setDrawCircles(false);
  lineDataSet1.setHighlightEnabled(false);
  LineDataSet lineDataSet2 = new LineDataSet(valueSet2, resp.label2);
  lineDataSet2.setColor(Color.parseColor("#FBB04E"));
  lineDataSet2.setDrawValues(false);
  lineDataSet2.setDrawCircleHole(false);
  lineDataSet2.setDrawCircles(false);
  lineDataSet2.setHighlightEnabled(false);
  LineDataSet lineDataSet3 = new LineDataSet(valueSet3, resp.label3);
  lineDataSet3.setColor(Color.parseColor("#7FA6DD"));
  lineDataSet3.setDrawValues(false);
  lineDataSet3.setDrawCircleHole(false);
  lineDataSet3.setDrawCircles(false);
  lineDataSet3.setHighlightEnabled(false);

  dataSets = new ArrayList<>();
  dataSets.add(lineDataSet1);
  dataSets.add(lineDataSet2);
  dataSets.add(lineDataSet3);
  return dataSets;
}

class MyPercentFormatter extends PercentFormatter{
  public MyPercentFormatter(){
      mFormat = new DecimalFormat("###,###,##0.00");
  }
}

class MyYAxisRenderer extends YAxisRenderer {

  public MyYAxisRenderer(ViewPortHandler viewPortHandler, YAxis yAxis, Transformer trans) {
      super(viewPortHandler, yAxis, trans);
  }

  @Override
  protected void drawYLabels(Canvas c, float fixedPosition, float[] positions, float offset) {

      mAxisLabelPaint.setColor(resColorNumberGreen);
      for (int i = 0; i < mYAxis.mEntryCount; i++) {
          // 处理Y轴坐标文字的颜色
          float v = mYAxis.mEntries[i];
          if (v > 0) {
              mAxisLabelPaint.setColor(resColorNumberRed);
          } else if (v < 0) {
              mAxisLabelPaint.setColor(resColorNumberGreen);
          } else {
              mAxisLabelPaint.setColor(mYAxis.getTextColor());
          }

          String text = mYAxis.getFormattedLabel(i);

          if (!mYAxis.isDrawTopYLabelEntryEnabled() && i >= mYAxis.mEntryCount - 1)
              return;

          c.drawText(text, fixedPosition, positions[i * 2 + 1] + offset, mAxisLabelPaint);
      }
  }
}