Update JLabel text added on another label

Question

I am trying to change Jlabel text which is added to another label if condition is met. But updated text is overlapping on previous text.

public class FGtest extends JFrame {

    public FGtest() {

        JLabel fg_layout = new JLabel();

        ImageIcon fgImageIcon = new ImageIcon(getClass().getResource("images/overall layout.JPG"));
        fg_layout.setIcon(fgImageIcon);

        Gradient gradient_layout = new Gradient();
        gradient_layout.add(fg_layout);

    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new FGtest();
            }
        });
    }


    @SuppressWarnings("serial")
    class Gradient extends JPanel {

        private String wpl_test = "";
        private String wpl1_status = "";
        private String wpl2_status = "";

        private Jedis jedis;

        public Gradient() {
            new Timer(1000, new TimerListener()).start();
        }

        private class TimerListener implements ActionListener {


            @Override
            public void actionPerformed(ActionEvent ae) {


                try {
                    jedis = new Jedis("192.168.0.140");
                    wpl_test = jedis.get("wpl_test");
                    wpl1_status = jedis.get("wpl1_status");
                    wpl2_status = jedis.get("wpl2_status");

                    repaint();


                } catch (Exception e) {

                }
            }
        }
        @Override
        public void paintComponent(Graphics g) {
            super.paintComponent(g);
            Graphics2D g2D = (Graphics2D) g;
            AlphaComposite alphaComposite = AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, 0.7 f);
            g2D.setComposite(alphaComposite);



            //-------wpl test----
            JLabel label11 = new JLabel();
            label11.setFont(new Font("Times New Roman", Font.BOLD, 30));
            label11.setBounds(800, 229, 300, 100);

            label11.setForeground(Color.orange);
            fg_layout.add(label11);



            if (wpl_test.equals("1")) {

                //              label2.setVisible(false);  
                //              fg_layout.remove(label2); 
                //              label2.setBounds(800,229,0,0); 

                //            JLabel label1 = new JLabel();
                //            label1.setFont(new Font("Times New Roman",Font.BOLD,30));
                //            label1.setBounds(800,229,300,100);
                //            label1.setText("wpl 1:1");             
                //            label1.setForeground(Color.orange);
                //            fg_layout.add(label1);

                label11.setText("wpl 1:1");


                if (wpl1_status.equals("pass")) {

                    g2D.setColor(Color.green);
                    int x1[] = {
                        610,
                        1057,
                        1017,
                        520
                    };
                    int y1[] = {
                        120,
                        350,
                        485,
                        220
                    };
                    g2D.fillPolygon(x1, y1, 4);
                } else if (wpl1_status.equals("fail")) {
                    g2D.setColor(Color.red);
                    int x1[] = {
                        610,
                        1057,
                        1017,
                        520
                    };
                    int y1[] = {
                        120,
                        350,
                        485,
                        220
                    };
                    g2D.fillPolygon(x1, y1, 4);
                }

            } else if (wpl_test.equals("2")) {

                //            label1.setVisible(false); 
                //            fg_layout.remove(label11); 
                //            label1.setBounds(800,229,0,0);

                //            JLabel label2 = new JLabel();
                //            label2.setFont(new Font("Times New Roman",Font.BOLD,30));
                //            label2.setBounds(800,229,300,100);
                //            label2.setText("wpl as such"); 
                //            label2.setForeground(Color.orange);
                //            fg_layout.add(label2);

                label11.setText("wpl as such");

                if (wpl2_status.equals("pass")) {

                    g2D.setColor(Color.green);
                    int x1[] = {
                        610,
                        1057,
                        1017,
                        520
                    };
                    int y1[] = {
                        120,
                        350,
                        485,
                        220
                    };
                    g2D.fillPolygon(x1, y1, 4);
                } else if (wpl2_status.equals("fail")) {
                    g2D.setColor(Color.red);
                    int x1[] = {
                        610,
                        1057,
                        1017,
                        520
                    };
                    int y1[] = {
                        120,
                        350,
                        485,
                        220
                    };
                    g2D.fillPolygon(x1, y1, 4);
                }

            }

        }
    }
}

1) For better help sooner, [edit] to add a [MCVE] or [Short, Self Contained, Correct Example](http://www.sscce.org/). 2) One way to get image(s) for an example is to hot link to images seen in [this Q&A](http://stackoverflow.com/q/19209650/418556). E.G. [This answer](https://stackoverflow.com/a/10862262/418556) hot links to an image embedded in [this question](https://stackoverflow.com/q/10861852/418556). — Andrew Thompson, Jan 31 '19 at 10:31
Don't create Swing components in the paintComponent() method. A painting method is for painting only. I don't see any reason for custom painting. If you want to use a JLabel, then just use a JLable and add the label to the panel. The label will automatically repaint itself whenever you change the text using the setText(...) method. And the layout manager will automatically position the label based on the labels preferred size. — camickr, Jan 31 '19 at 15:24

score 0 · Answer 1 · answered Jan 31 '19 at 12:44

A general approach to problems like this is model-view-controller or model-view-presenter paradigm.

What I see in your code is

class Gradient extends JPanel {

    private String wpl_test = "";
    private String wpl1_status = "";
    private String wpl2_status = "";
    ...

i.e. the values are directly in your view.

It is generally better to separate aspects like data (model) and view (JLabel, ...) and logic (controller/presenter).

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeSupport;

public class Model {

    public static final String KEY_WPL_TEST = "wpl_test";
    public static final String KEY_WPL1_STATUS = "wpl1_status";
    public static final String KEY_WPL2_STATUS = "wpl2_status";

    private String wpl_test = "";
    private String wpl1_status = "";
    private String wpl2_status = "";

    private final PropertyChangeSupport pcs = new PropertyChangeSupport(this);

    /**
     * The default constructor. 
     */
    public Model() {
        super();
    }

    public String getWpl_test() {
        return wpl_test;
    }

    public void setWpl_test(String wpl_test) {
        PropertyChangeEvent event = new PropertyChangeEvent(this, KEY_WPL_TEST, this.wpl_test, wpl_test);
        this.wpl_test = wpl_test;
        pcs.firePropertyChange(event);
    }

    public String getWpl1_status() {
        return wpl1_status;
    }

    public void setWpl1_status(String wpl1_status) {
        PropertyChangeEvent event = new PropertyChangeEvent(this, KEY_WPL1_STATUS, this.wpl1_status, wpl1_status);
        this.wpl1_status = wpl1_status;
        pcs.firePropertyChange(event);
    }

    public String getWpl2_status() {
        return wpl2_status;
    }

    public void setWpl2_status(String wpl2_status) {
        PropertyChangeEvent event = new PropertyChangeEvent(this, KEY_WPL2_STATUS, this.wpl2_status, wpl2_status);
        this.wpl2_status = wpl2_status;
        pcs.firePropertyChange(event);
    }

    public void addPropertyChangeListener(PropertyChangeListener listener) {
        pcs.addPropertyChangeListener(listener);
    }

    public void removePropertyChangeListener(PropertyChangeListener listener) {
        pcs.removePropertyChangeListener(listener);
    }

    public void addPropertyChangeListener(String propertyName, PropertyChangeListener listener) {
        pcs.addPropertyChangeListener(propertyName, listener);
    }

    public void removePropertyChangeListener(String propertyName, PropertyChangeListener listener) {
        pcs.removePropertyChangeListener(propertyName, listener);
    }

}

Then, have a View

import java.awt.BorderLayout;

import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JPanel;

public class View extends JPanel {
    private final JLabel jlWpl1_status;
    private final JLabel jlWpl2_status;
    private final JLabel jlWpl_test;
    private final JButton jbUpdate;

    /**
     * The default constructor.
     */
    public View() {
        super();

        jlWpl1_status = new JLabel();
        jlWpl2_status = new JLabel();
        jlWpl_test = new JLabel();
        jbUpdate = new JButton("push me");
        // arrange the view
        this.setLayout(new BorderLayout());
        this.add(jlWpl1_status, BorderLayout.EAST);
        this.add(jlWpl_test, BorderLayout.CENTER);
        this.add(jlWpl2_status, BorderLayout.WEST);
        this.add(jbUpdate, BorderLayout.SOUTH);
    }

    public void display(Model model) {
        jlWpl1_status.setText(model.getWpl1_status());
        jlWpl2_status.setText(model.getWpl2_status());
        jlWpl_test.setText(model.getWpl_test());
    }

    public JButton getJbUpdate() {
        return jbUpdate;
    }
}

And finally controller or presenter, like

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;

public class Controller implements PropertyChangeListener {
    /**
     * The Constant WHAT.
     */
    public static final String WHAT = "$Id$";

    private final Model model;

    private View view;

    /**
     * The default constructor.
     */
    public Controller(Model model, View view) {
        super();
        this.model = model;
        this.model.addPropertyChangeListener(this);
        this.view = view;
        this.view.display(model);
        this.view.getJbUpdate().addActionListener(x -> {
            model.setWpl_test("button pressed");
        });
    }

    @Override
    public void propertyChange(PropertyChangeEvent evt) {
        view.display(model);
    }

}

Now, if there is a main method / Application

import javax.swing.JFrame;
import javax.swing.SwingUtilities;

public class Application {

    /**
     * The default constructor. 
     */
    public Application() {
        super();
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        View view = new View();
        Model model = new Model();
        frame.add(view);
        frame.setSize(200, 200);
        new Controller(model, view);

        new Thread(() -> {
            try {
                Thread.sleep(5000L);

                SwingUtilities.invokeLater(() -> {
                    model.setWpl1_status("somewpl1status");
                    model.setWpl2_status("somewpl2status");
                    model.setWpl_test("sometest");
                });
            } catch (InterruptedException e) {
                throw new RuntimeException(e);
            }
        }).start();

        frame.setVisible(true);
    }
}

the values are automatically updated whenever you call any setter of the model, regardless whether called from a Thread or via button press.

if setOpaque(true) works it is just a workaround. The reason is different — michaeak, Feb 12 '19 at 08:59

Update JLabel text added on another label

1 Answers1