Develop Reference

Implementing custom barchart in android

I'm trying to implement a custom barchart
which should look exactly like this. I tried mpChart but could only get this far
barDataSet = new BarDataSet(barEntries, "");
barData = new BarData(barDataSet);
barData.setBarWidth(.5f);
barChart.setData(barData);
barDataSet.setColors(getResources().getColor(R.color.colorPrimary));
barDataSet.setValueTextColor(Color.BLACK);
barDataSet.setDrawValues(false);
barChart.getXAxis().setDrawAxisLine(false);
barChart.setDrawGridBackground(false);
barChart.getXAxis().setDrawGridLines(false);
barChart.getAxisLeft().setDrawGridLines(false);
barChart.getAxisRight().setDrawGridLines(false);
barChart.getAxisLeft().setEnabled(false);
barChart.getAxisRight().setEnabled(false);
barChart.getLegend().setEnabled(false);
barChart.setPinchZoom(false);
barChart.setDescription(null);
barChart.setTouchEnabled(false);
barChart.setDoubleTapToZoomEnabled(false);
barChart.setExtraOffsets(20, 0, 0, 30);
XAxis xAxis = barChart.getXAxis();
xAxis.setPosition(XAxis.XAxisPosition.BOTTOM);
xAxis.setTextSize(14f);
xAxis.setTextColor(Color.BLACK);
xAxis.setYOffset(5);
xAxis.setDrawLabels(true);
xAxis.setGranularityEnabled(true);
xAxis.setGranularity(1f);
xAxis.setXOffset(30);
xAxis.setValueFormatter(new IndexAxisValueFormatter(xAxisLabel));
xAxis.setCenterAxisLabels(true);
barChart.invalidate();
I tried almost all possible examples and questions here, couldn't get the label to centre of the bars. Is it possible to put the labels exactly below the bars in non grouped bars? all the solutions I saw is only for grouped bars or combined charts.

I was plotting the x axis values from 1. when changed it to 0 and removed
xAxis.setCenterAxisLabels(true);
and i was able to centre the axis labels

You need to create a custom renderer for it.
Subclass BarChartRenderer and then call:
barChart.setRenderer(new MyBarChartRenderer(barChart, barChart.getAnimator(), barChart.getViewPortHandler()))
It will even allow you to alter the shape of it as described here.
But I think what you're looking for comes really close to this.

Download the MPAndroidChart Source from here. Then, you can customize the code according to your need and add it your project by
Clicking on File>New>Import Module.

OSMdroid - Replace empty grid background when no tile available (offline)

I'm using OSMdroid library in my project to display map tiles (it's a shape with lines and blank background) from my company local sever in my app. The thing is when I use the app in offline mode and I browse the map shows an empty grey grid background for the tiles that aren't in the cache, and I want to change that empty grey grid for an blank background image/tile.
The only workaround that I've found to achieve this is the following:
Add a tile overlay and set setLoadingBackgroundColor and setLoadingLineColor to Color.WHITE, and then set the TileSource from the local server from OnlineTileSourceBase. I know this is not quite performant, so is there a better way to do this? Thanks in advance!
final ITileSource tileSource = new OnlineTileSourceBase(...)
{
#Override
public String getTileURLString(MapTile aTile) {
return getBaseUrl() + aTile.getX() + "+" + aTile.getY() + "+" + aTile.getZoomLevel();
}
};
tileProvider = new MapTileProviderBasic(context, tileSource);
tilesOverlay = new TilesOverlay(tileProvider , context);
tilesOverlay.setLoadingBackgroundColor(Color.WHITE);
tilesOverlay.setLoadingLineColor(Color.WHITE);
this.map.getOverlays().add(tilesOverlay);
this.map.setTileSource(tileProvider.getTileSource());
map.invalidate();

Your code is an example on adding a secondary tile overlay. That's useful for when you need another raster graphics overlay on top of the map imagery.
You can also change the loading lines and background for the existing and default tiles overlay. This should get you going
mMapView.getOverlayManager().getTilesOverlay().setLoadingBackgroundColor(Color.TRANSPARENT);
mMapView.getOverlayManager().getTilesOverlay().setLoadingLineColor(Color.TRANSPARENT);

Vaadin Charts: Pie chart won't update dynamically

I created a Vaadin pie chart with following code.
Chart chart = new Chart(ChartType.PIE);
DataSeries dataSeries = new DataSeries("Logins");
chart.getConfiguration().setSeries(dataSeries);
I need to update my chart dynamically. I tried following (this code gets executed whenever new data is available).
adding new item:
dataSeries.add(new DataSeriesItem("New item", value), true, false);
updating existing item:
DataSeriesItem dataSeriesItem = dataSeries.get(0);
dataSeriesItem.setY(newValue);
dataSeries.update(dataSeriesItem);
But none of the above worked.
The only solution I could find is clearing the chart (chart.clear()), re, populating the data series and re drawing the chart (chart.drawChart()).
This method is not optimal since it re-draws the chart, and also the selection in the chart gets lost.
Does pie chart support dynamic updating? Can anyone suggest a way to fix this?

Try to call chart.getConfiguration().addSeries(dataSeries) before updating items. If that doesn't work, I think you should re-draw your chart.

I had the same problem and fixed it with chart.drawChart() after updating the data series in configurations (chart.getConfiguration.setSeries(newSeries)).
In my case (vaadin version 7.6.3), chart.clear() was not required.
There are other more complicated ways like vaadin-push plugin as well which I didn't find necessary for my case.

I know this question is old, but I will share how I solved this problem to Chart Pie in DChart 1.7.0.
DataSeries dataSeries = new DataSeries();
dataSeries.newSeries();
dataSeries.add( "Food", 500);
dataSeries.add( "Clothes", 1000);
chart.setDataSeries(dataSeries);
chart.show(); //this will update the chart in the browser;

Late to the question, but I encountered similar problem in 2020, I solved it using below code:
dataSeries.clear();
dataSeries.add(new DataSeriesItem("Expense", 120));
dataSeries.add(new DataSeriesItem("Saving", 20));
dataSeries.add(new DataSeriesItem("Balance", 100));
chart.getConfiguration().setSeries(dataSeries);
chart.drawChart();

JfreeChart background image not showing up

I'm creating a chart in a servlet, and it works great.
chart = ChartFactory.createPieChart("Smart Chart", ds, true, true,
true);
PiePlot plot = (PiePlot) chart.getPlot();
ImageIcon icon = new ImageIcon(bgImageStr);
plot.setBackgroundPaint(Color.CYAN);
plot.setBackgroundAlpha(0.15f);
chart.setBackgroundPaint(Color.WHITE);
chart.getTitle().setBackgroundPaint(Color.PINK);
chart.setBackgroundImage(icon.getImage());
Problem is, the background image is not showing up. I've tried the plot and chart bg, and all kinds of other stuff. It must be simple, anyone see what is wrong? I'm just using the write to PNG to dump it to the browser. It shows up fine, with all the color changes, just no image.

OK, OP here, I fixed it.
I was calling the servlet from itself, and it did not like that. I used a resource (as suggested) and it worked fine without the infinite recursion (imagine that).

apply
try{
Thread.sleep(100);
}
catch(InterruptedException IntExp)
{
//your implementation
}
before chart.setBackgroundImage(icon.getImage());

How to disable scaling in JFreeChart?

We're using JFreeChart to build an engine to display graphs. This is a web service that runs on Tomcat + Java 1.5.0, and renders charts to PNGs and JPEGs (using ChartUtilities.writeChartAs{PNG,JPEG}() ).
We've run into a problem where JFreeChart seems to scale everything inside the Plot area, but only by a few pixels. The result is that the graph looks inconsistent, e.g.:
Minor ticks are sometimes stretched horizontally, so that they seem to be two pixels wide instead of one.
We use a small image in the top-right of the plot area as a watermark. This is stretched by one pixel horizontally and vertically somewhere near (but not exactly) its middle.
Background grid lines seem to appear on sub-pixel boundaries. I have not found a way to create an accurately dotted grid line.
We have tried both 1.0.9 and 1.0.13, with exactly the same results (except for the minor ticks, which were not available in the older version). Also, rendering the image to a Frame instead of JPEG/PNG produced an identical result.
Help is greatly appreciated, in advance :)
EDIT: An SSCCE:
#Test
public void testScaling1() throws InterruptedException {
// Load Image:
Component dummy = new Component() {};
MediaTracker tracker = new MediaTracker(dummy);
Image img = Toolkit.getDefaultToolkit().getImage("C:\\My\Image.gif");
tracker.addImage(img, 0);
tracker.waitForAll();
// Build Data set and base chart.
TimeSeriesCollection dataset = new TimeSeriesCollection();
TimeSeries ts = new TimeSeries("Sample");
ts.add(new Second(0, 0, 0, 1, 1, 1900), 1.0);
ts.add(new Second(1, 0, 0, 1, 1, 1900), 3.0);
ts.add(new Second(2, 0, 0, 1, 1, 1900), 4.0);
ts.add(new Second(3, 0, 0, 1, 1, 1900), 2.0);
dataset.addSeries(ts);
JFreeChart chart = ChartFactory.createTimeSeriesChart(
"blabla",
null,
null,
dataset,
true,
true,
false
);
// Add BG image in top-right corner.
XYPlot xy = chart.getXYPlot();
xy.setBackgroundAlpha(0.0F);
xy.setBackgroundImage(img);
xy.setBackgroundImageAlignment(Align.NORTH_WEST);
xy.setBackgroundImageAlpha(1.0F);
paintChart(chart);
}
Use an image with small-font text, or a grid. This will show the scaling effect on the background image.
Edit 2:
We've resorted to subclassing or proxying Renderers and drawing the label in text in their drawItem() (or similar) methods. This works well.
However, minor ticks are now a problem - they also seem to be getting scaled. E.g.: See the 9th and 15th ticks.
look at the bottom http://img14.imageshack.us/img14/3625/76676732.jpg

I am unable to reproduce the effect you describe using either saveChartAsJPEG() or writeChartAsPNG() with version 1.0.13, Java 1.5, Mac OS X, in code like this:
try {
ChartUtilities.writeChartAsPNG(new FileOutputStream(
new File("test.png")), chart, 600, 400);
} catch (IOException ex) {
ex.printStackTrace();
}
Does the screen exhibit the same artifacts? What happens when you change the WIDTH and HEIGHT parameters or omit the watermark? Are you using special fonts with unusual metrics? Have you tried a different platform?
You can run TimeSeriesChartDemo1 as follows:
java -cp jfreechart-1.0.13.jar:jcommon-1.0.16.jar org.jfree.chart.demo.TimeSeriesChartDemo1
Mac OS 10.5.8, Java 1.5.0_24, JFreeChart 1.0.13, TimeSeriesDemo1, using saveChartAsPNG(), ImageIO.read() and setBackgroundImage(). setBackgroundImageAlignment(Align.NORTH_WEST) is a little funky, though.