CODEWITHSUNDEEP
javaswingjfreechart
sebaoka
sebaoka

Reputation: 119

How to update dataset in JFreeChart Bar Chart

I have got a JFrame, within this frame there is a JPanel, in a JPanel there is a JFreeChart (chart takes dataset from a method) and this chart is added to ChartPanel created in JPanel, then ChartPanel is added to JPanel. Also I have got JComboBox in JPanel, if I change option in that JComboBox an ActionListener updates value of dataset. Also method which return dataset, takes a string from JComboBox(data of dataset depends on JComboBox output). So if I change option in JComboBox I would want to update JFreeChart with new dataset and display it on screen. I know that I need to add code in that ActionListener but I don't what I should add there, is there any method which updates already created JFreeChart?

private class PanelChart extends JPanel { {
    this.setLayout(new BorderLayout());

    // Create Dataset
    //method GUIImplementation.GetDataForChart takes as an input value of combobox

    CategoryDataset dataset = GUIImplementation.GetDataForChart(comboBoxCrimeTypeChart.getSelectedItem().toString());


    //Create chart
    JFreeChart crimeNumberBarChart = ChartFactory.createBarChart(
        "Number of crimes by type", //Chart Title
        "Fallen within", // Category axis
        "Number of crimes", // Value axis
        dataset,
        PlotOrientation.VERTICAL,
        true,true,false
        );
    ChartPanel panelCrimeNumberBarChart = new ChartPanel(crimeNumberBarChart);
    this.add(panelCrimeNumberBarChart, BorderLayout.CENTER);

    PanelChartSouth panelChartSouth = new PanelChartSouth(); //there is a combobox
    this.add(panelChartSouth, BorderLayout.SOUTH);
}}

private class ChartButtonListener implements ActionListener {
    @Override
    public void actionPerformed(ActionEvent e) {
        if(e.getSource() == backChart) {
            SizeAndTitleSetter(0);
            SwapPanelChart(0);
        } else if(e.getSource() == comboBoxCrimeTypeChart) { //comboBoxCrimeTypeChart is a JComboBox from PanelChartSouth
            String crimeType = comboBoxCrimeTypeChart.getSelectedItem().toString();
            System.out.println(crimeType);
            dataset = GUIImplementation.GetDataForChart(crimeType); // dataset updated
        }
    }
}

So far I only managed to update somehow that chart by removing PanelChart from JFrame then create new PanelChart and add it to JFrame and use repaint and revalidate. It worked if I changed option in JComboBox once, after second change everything started to brake on screen, old chart didn't want to dissapear and new chart was under it and I could see it if I resized screen.

Upvotes: 1

Views: 2187

Answers (2)

trashgod
trashgod

Reputation: 205785

You can update an existing chart's dataset, as shown in these examples; when you update the model (dataset), the listening plot (view) will update itself accordingly; concrete implementations of CategoryDataset typically provide suitable mutators.

DefaultCategoryDataset model = …
…
@Override
public void actionPerformed(ActionEvent e) {
    model.setValue(…);
}

You can replace an existing chart's dataset using the relevant plot's setDataset() method.

CategoryPlot plot = (CategoryPlot) chart.getPlot();
…
@Override
public void actionPerformed(ActionEvent e) {
    plot.setDataset(…);
}

While it's technically possible to replace the enclosing view component, as suggested here, it's generally better to update or replace the model, as suggested here.

Upvotes: 2

sebaoka
sebaoka

Reputation: 119

I found out an answer its working but there is a small problem with it. So my ActionListener looks like that now:

private class ChartButtonListener implements ActionListener {
    @Override
    public void actionPerformed(ActionEvent e) {
        if(e.getSource() == backChart) {
            SizeAndTitleSetter(0);
            SwapPanelChart(0);
        } else if(e.getSource() == comboBoxCrimeTypeChart) {
            SwingUtilities.invokeLater(() -> {
                frame.remove(panelChart);
                panelChart = new PanelChart();
                frame.add(panelChart);
                frame.pack();
                frame.invalidate();
                frame.revalidate();
                frame.repaint();
            });
        }
    }
}

After I have added SwingUtilities.invokeLater it started to work well, but now problem is that program slows down after changing JComboBox option few times. Computer's fans are going crazy, now I don't know if this is a problem with this part of code or I made an error somewhere. When I go back to main menu of my program and use other components its work same as before.

I found out why it started to be laggy, in a class PanelChartSouth I was adding actionListener to JComboBox, and after every removing and creating new PanelChart next actionListener was added to JComboBox. So prevent it I have put operation of adding action listeners to if statement

      if(ifActionListenerSet == false) {

        ifActionListenerSet = true;
    ChartButtonListener chartButtonListener = new ChartButtonListener();
    backChart.addActionListener(chartButtonListener);
    comboBoxCrimeTypeChart.addActionListener(chartButtonListener);
    }

Now everything is fine.

Upvotes: 1

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