时间序列数据不被跨$ P $正确PTED [英] Time series data not being interpreted properly

问题描述

我试图创建一个使用时间序列的简单折线图。问题是，androidplot未正确从阵列显示时间值，即该日期是关闭。日期应该是：

I'm trying to create a simple line chart using a time series. The problem is that androidplot is not properly displaying the time values from the array, i.e. the dates are off. The dates should be:

2001年1月1日，2001年2月1日，2001年3月1日，2001年4月1日，2001年5月1

Jan 1 2001, Feb 1 2001, Mar 1 2001, Apr 1 2001, May 1 2001

但我正在逐渐：

2001年1月1日，二零零一年一月三十零日，2001年3月1日，2001年3月31日，2001年5月1日

Jan 1 2001, Jan 30 2001, Mar 1 2001, Mar 31 2001, May 1 2001

您可以从格式化的哪些数据androidplot的调试信息已经跨preTED看到的。我使用JodaTime时间。 code是在这里：

You can see from the the debug info in the formatted what data androidplot has interpreted. I am using JodaTime for time. Code is here:

公共类VisualizeFragment扩展片段{

public class VisualizeFragment extends Fragment {

public static final String TAG = Config.PRE + VisualizeFragment.class.getSimpleName();

private XYPlot plot;

public VisualizeFragment() {
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

    View v = inflater.inflate(R.layout.simple_xy_plot_example, container, false);

    // initialize our XYPlot reference:
    plot = (XYPlot) v.findViewById(R.id.mySimpleXYPlot);

    // Create a couple arrays of y-values to plot:
    Number[] weights = {150, 180, 179, 170, 175};
    Number[] xyears = {
            978307200,  // 2001
            1009843200, // 2002
            1041379200, // 2003
            1072915200, // 2004
            1104537600  // 2005
    };
    Number[] years = {
            new DateTime(2001, 1, 1, 0, 0).getMillis() / 1000,
            new DateTime(2001, 2, 1, 0, 0).getMillis() / 1000,
            new DateTime(2001, 3, 1, 0, 0).getMillis() / 1000,
            new DateTime(2001, 4, 1, 0, 0).getMillis() / 1000,
            new DateTime(2001, 5, 1, 0, 0).getMillis() / 1000,
    };

    XYSeries series1 = new SimpleXYSeries(
            Arrays.asList(years),
            Arrays.asList(weights),
            "Weight");

    // Create a formatter to use for drawing a series using LineAndPointRenderer
    // and configure it from xml:
    LineAndPointFormatter series1Format = new LineAndPointFormatter();
    series1Format.setPointLabelFormatter(new PointLabelFormatter());
    series1Format.configure(getActivity().getApplicationContext(), R.xml.line_point_formatter_with_plf1);

    // add a new series' to the xyplot:
    plot.addSeries(series1, series1Format);

    // reduce the number of range labels
    //plot.setTicksPerRangeLabel(3);
    plot.getGraphWidget().setDomainLabelOrientation(-45);

    // draw a domain tick for each year:
    plot.setDomainStep(XYStepMode.SUBDIVIDE, years.length);


    plot.setDomainValueFormat(new Format() {

        // create a simple date format that draws on the year portion of our timestamp.
        // see http://download.oracle.com/javase/1.4.2/docs/api/java/text/SimpleDateFormat.html
        // for a full description of SimpleDateFormat.
        private SimpleDateFormat dateFormat = new SimpleDateFormat("MMM dd");

        @Override
        public StringBuffer format(Object obj, StringBuffer toAppendTo, FieldPosition pos) {

            // because our timestamps are in seconds and SimpleDateFormat expects milliseconds
            // we multiply our timestamp by 1000:
            long timestamp = ((Number) obj).longValue() * 1000;
            Date date = new Date(timestamp);

            Log.d(TAG, "formatting date=" + new SimpleDateFormat("MMMM dd, yyyy").format(date));

            return dateFormat.format(date, toAppendTo, pos);
        }

        @Override
        public Object parseObject(String source, ParsePosition pos) {
            return null;

        }
    });


    return v;

}

}

推荐答案

我相信问题是，你是均匀细分您的域名（XYStepMode.SUBDIVIDE），而是因为你的xVals是划时代值它们不是均匀分布; 2001年1月1日和2001年2月1日之间的毫秒是不一样的2001年2月1日和2001年3月1日，等之间的毫秒导致的差异。

I believe the problem is that you are uniformly subdividing your domain (XYStepMode.SUBDIVIDE) but because your xVals are epoch values they are not uniformly distributed; the milliseconds between Jan 1, 2001 and Feb 1, 2001 is not the same as the milliseconds between Feb 1, 2001 and Mar 1, 2001, etc. which causes the discrepancy.

我的建议是用我作为你的域值，而不是具有划时代值，然后用我来查找你的域值格式code正确的时代价值。这将涉及使2的变化。首先，利用我作为你的函数f（x）

What I would suggest is to use i as your domain values instead of epoch values and then use i to lookup the correct epoch value in your domain value format code. This would involve making 2 changes. First, to use i as your f(x):

// I've just removed the 'years' param here, which tells SimpleXYSeries
// to use an implicit value of 'i' for getY(i).
XYSeries series1 = new SimpleXYSeries(Arrays.asList(weights),"Weight");

，然后更改您的格式方法如下：

And then change your format method to this:

@Override
public StringBuffer format(Object obj, StringBuffer toAppendTo, FieldPosition pos) {
    int i = ((Number) obj).intValue();
    Date date = years[i];
    Log.d(TAG, "formatting date=" + new SimpleDateFormat("MMMM dd, yyyy").format(date));
    return dateFormat.format(date, toAppendTo, pos);
}

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