How to add x axis as datetime label in MPAndroidChart?

问题

I implemented line chart (MPAndroidChart library) for temperature report in my project.In X axis datetime should be plotted and Y axis temperature should be plotted.

I just added datetime as string in X axis label but it's collapsed. So please anyone guide me.

回答1:

Try the following.

To set the X Axis

 XAxis xAxis = mChart.getXAxis();
        xAxis.setPosition(XAxis.XAxisPosition.BOTTOM);
        xAxis.setValueFormatter(new MyXAxisValueFormatter());
        xAxis.setLabelsToSkip(0);

Create a new class MyXAxisValueFormatter implement XAxisValueFormatter

public class MyXAxisValueFormatter implements XAxisValueFormatter {

@Override
public String getXValue(String dateInMillisecons, int index, ViewPortHandler viewPortHandler) {
    try {

        SimpleDateFormat sdf = new SimpleDateFormat("dd MMM");
        return sdf.format(new Date(Long.parseLong(dateInMillisecons)));

    } catch (Exception e) {

        return  dateInMillisecons;
    }
}

Hope this helps

回答2:

Using version 3.0+ of the MPAndroidChart:

Set formatter to the x axis (created below):

// Formatter to adjust epoch time to readable date
lineChart.xAxis.setValueFormatter(new LineChartXAxisValueFormatter());

Create a new class LineChartXAxisValueFormatter:

public class LineChartXAxisValueFormatter extends IndexAxisValueFormatter {

    @Override
    public String getFormattedValue(float value) {

        // Convert float value to date string
        // Convert from seconds back to milliseconds to format time  to show to the user
        long emissionsMilliSince1970Time = ((long) value) * 1000;

        // Show time in local version
        Date timeMilliseconds = new Date(emissionsMilliSince1970Time);
        DateFormat dateTimeFormat = DateFormat.getDateInstance(DateFormat.MEDIUM, Locale.getDefault());

        return dateTimeFormat.format(timeMilliseconds);
    }
}

When the entries are added to the chartDataArray they are added in seconds, not milliseconds, to avoid potential precision issues with inputting as a float (i.e. milliseconds divided by 1000).

chartDataArray.add(new Entry(secondsSince1970Float, yValueFloat));

Happy coding!

回答3:

If it still actually...

class DateAxisValueFormatter implements IAxisValueFormatter {
  private String[] mValues;

  SimpleDateFormat sdf = new SimpleDateFormat("yyyy.MM.dd.hh");

  public DateAxisValueFormatter(String[] values) {
      this.mValues = values; }


   @Override
   public String getFormattedValue(float value, AxisBase axis) {
        // "value" represents the position of the label on the axis (x or y)
        return mValues[(int) value];
      }
    }

And your must on Create put String[] values (public DateAxisValueFormatter(String[] values) ) where each value is a DateString. Data series Entries for X (new Entry(forX,forY)) must be a flat array = 0,1,2,3,4
Sorry, my poor English, I am from Russia. From 1988 main chief of RealTime Control System Developer Company for Hydro Power Plants (www.asu-epro.ru). Borodatov Michael miclosoft@mail.ru

来源：https://stackoverflow.com/questions/41426021/how-to-add-x-axis-as-datetime-label-in-mpandroidchart

标签

android

mpandroidchart