Question

I want to get some values from a table and store them in a multiple line chart. When I use only one column (fat) it displays a graph correctly, but when i add another column or two it gives me an error saying : Dataset and renderer should not be null and should not have the same number of series. Could you please help me fix the error?

  public XYMultipleSeriesDataset getFatDataset() 页: 1

    XYMultipleSeriesDataset dataset = new XYMultipleSeriesDataset();
    Cursor c = database.rawQuery("select * from dailystats;", null);
    float i = 1.0f;

    c.moveToFirst();
    XYSeries seriesFat = new XYSeries("Fat");
    while(!c.isAfterLast()) 页: 1
        seriesFat.add(i++, c.getDouble(2));

        c.moveToNext();
    iii
    dataset.addSeries(seriesFat);

   i = 1.0f;
    c.moveToFirst();
    XYSeries seriesProtein = new XYSeries("Protein");
    while(!c.isAfterLast()) 页: 1

        seriesProtein.add(i++, c.getDouble(3));

        c.moveToNext();
    iii
    dataset.addSeries(seriesProtein);

    c.moveToFirst();
    i = 1.0f;
    XYSeries seriesCarbs = new XYSeries("Carbs");
    while(!c.isAfterLast()) 页: 1

        seriesCarbs.add(i++, c.getDouble(4));
        c.moveToNext();
    iii
    dataset.addSeries(seriesCarbs);

    return dataset;
iii

这里是编制图表的法典:

public class ChartActivity 页: 1

public Intent getIntent(Context context)

页: 1

XYMultipleSeriesDataset dataset = new XYMultipleSeriesDataset();


XYMultipleSeriesRenderer mrenderer = new XYMultipleSeriesRenderer();
XYSeriesRenderer renderer = new XYSeriesRenderer();
mrenderer.addSeriesRenderer(renderer);

DatabaseAdapter dba = new DatabaseAdapter(context);
dba.open();


Intent intent = ChartFactory.getLineChartIntent(context, dba.getFatDataset(), mrenderer,"line graph");
dba.close();

return intent;

iii

Answer 1

所报的错误十分清楚:Dataset和iers不应成为无效,而不应有相同的系列,即你重新使用不同的系列和系列代号。注:

//...
dataset.addSeries(seriesFat);
//....
dataset.addSeries(seriesCarbs);
//....

但只有<>>one <>>oneXYSeriesRenderer(:

mrenderer.addSeriesRenderer(renderer);

在我看来,你的守则应当开始简单地在<条码>XYMultipleSeriesRenderer()上添加另一条内容。

XYSeriesRenderer renderer2 = new XYSeriesRenderer();
mrenderer.addSeriesRenderer(renderer2);

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