Using Step Charts


Using Step Charts

[doc_header] [last_updated_for version=0.3d]

Overview

This tutorial demonstrates how to create a basic StepChart.

layout/main.xml




    

MyActivity.java

import android.app.Activity;
import android.graphics.*;
import android.os.Bundle;
import com.androidplot.Plot;
import com.androidplot.xy.SimpleXYSeries;
import com.androidplot.series.XYSeries;
import com.androidplot.xy.*;

import java.text.DecimalFormat;
import java.text.FieldPosition;
import java.text.Format;
import java.text.ParsePosition;
import java.util.Arrays;

public class MyActivity extends Activity
{

    private XYPlot mySimpleXYPlot;

    @Override
    public void onCreate(Bundle savedInstanceState)
    {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

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

        // y-vals to plot:
        Number[] series1Numbers = {1, 2, 3, 4, 2, 3, 4, 2, 2, 2, 3, 4, 2, 3, 2, 2};

        // create our series from our array of nums:
        XYSeries series2 = new SimpleXYSeries(
                Arrays.asList(series1Numbers),
                SimpleXYSeries.ArrayFormat.Y_VALS_ONLY,
                "Thread #1");

        mySimpleXYPlot.getGraphWidget().getGridBackgroundPaint().setColor(Color.WHITE);
        mySimpleXYPlot.getGraphWidget().getGridLinePaint().setColor(Color.BLACK);
        mySimpleXYPlot.getGraphWidget().getGridLinePaint().setPathEffect(new DashPathEffect(new float[]{1,1}, 1));
        mySimpleXYPlot.getGraphWidget().getDomainOriginLinePaint().setColor(Color.BLACK);
        mySimpleXYPlot.getGraphWidget().getRangeOriginLinePaint().setColor(Color.BLACK);
        mySimpleXYPlot.getGraphWidget().setMarginRight(5);

        mySimpleXYPlot.setBorderStyle(Plot.BorderStyle.SQUARE, null, null);
        mySimpleXYPlot.getBorderPaint().setStrokeWidth(1);
        mySimpleXYPlot.getBorderPaint().setAntiAlias(false);
        mySimpleXYPlot.getBorderPaint().setColor(Color.WHITE);

        // Create a formatter to use for drawing a series using LineAndPointRenderer:
        LineAndPointFormatter series1Format = new LineAndPointFormatter(
                Color.rgb(0, 100, 0),                   // line color
                Color.rgb(0, 100, 0),                   // point color
                Color.rgb(100, 200, 0));                // fill color

        // setup our line fill paint to be a slightly transparent gradient:
        Paint lineFill = new Paint();
        lineFill.setAlpha(200);
        lineFill.setShader(new LinearGradient(0, 0, 0, 250, Color.WHITE, Color.BLUE, Shader.TileMode.MIRROR));

        StepFormatter stepFormatter  = new StepFormatter(Color.rgb(0, 0,0), Color.BLUE);
        stepFormatter.getLinePaint().setStrokeWidth(1);

        stepFormatter.getLinePaint().setAntiAlias(false);
        stepFormatter.setFillPaint(lineFill);
        mySimpleXYPlot.addSeries(series2, stepFormatter);

        // adjust the domain/range ticks to make more sense; label per tick for range and label per 5 ticks domain:
        mySimpleXYPlot.setRangeStep(XYStepMode.INCREMENT_BY_VAL, 1);
        mySimpleXYPlot.setDomainStep(XYStepMode.INCREMENT_BY_VAL, 1);
        mySimpleXYPlot.setTicksPerRangeLabel(1);
        mySimpleXYPlot.setTicksPerDomainLabel(5);

        // customize our domain/range labels
        mySimpleXYPlot.setDomainLabel("Time (Secs)");
        mySimpleXYPlot.setRangeLabel("Server State");

        // get rid of decimal points in our domain labels:
        mySimpleXYPlot.setDomainValueFormat(new DecimalFormat("0"));

        // create a custom formatter to draw our state names as range tick labels:
        mySimpleXYPlot.setRangeValueFormat(new Format() {
            @Override
            public StringBuffer format(Object obj, StringBuffer toAppendTo, FieldPosition pos) {
                Number num = (Number) obj;
                switch(num.intValue()) {
                    case 1:
                        toAppendTo.append("Init");
                        break;
                    case 2:
                        toAppendTo.append("Idle");
                        break;
                    case 3:
                        toAppendTo.append("Recv");
                        break;
                    case 4:
                        toAppendTo.append("Send");
                        break;
                    default:
                        toAppendTo.append("Unknown");
                        break;
                }
                return toAppendTo;
            }

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

        // by default, AndroidPlot displays developer guides to aid in laying out your plot.
        // To get rid of them call disableAllMarkup():
        mySimpleXYPlot.disableAllMarkup();

    }
}