Question

I have a problem.
I have an element that would JPanel.
In this JPanel would be four JButtons and image.
This image is ‘green LED lights’ that would change depending on which JButton would be pressed.
It works very well.
But also I want the JComboBox to change this paramter.

And here’s the problem.
Although the parameter (from 1 to 4) is changing,(this shows JLabel near LEDs),
but the picture (LED lights) do not want to change it to the right one.

screenshot

The program is divided into 3 classes.

MyFrame.class This main class.

public class MyFrame extends JFrame {

int ctrlTriggers = 1;
private JLabel label = new JLabel();
private Triggers triggers;
private String[] typeTrig = {"1", "2", "3", "4"};

public MyFrame() {
  JFrame frame = new JFrame("JComboBox Problem");
  frame.setBounds(50, 0, 800, 240);
  frame.setLayout(new BorderLayout());


  int tvalue = 1;
  String tstr = Integer.toString(tvalue);
  JPanel panelTrig = new JPanel(new BorderLayout());
  label = new JLabel(tstr, 4);
  panelTrig.add(label);
  final JLabel et = label;

  triggers = new Triggers(typeTrig, "trigger " + Integer.toString(1));

  triggers.addChangeListener(new ChangeListener() {
     public void stateChanged(ChangeEvent e) {
        Triggers tr = (Triggers) e.getSource();
        int vol;

        vol = (int) tr.getValue();
        et.setText(Integer.toString(vol));

     }
  });

  panelTrig.add(triggers, BorderLayout.LINE_START);



  // JCOMBOBOX
  JPanel pCombo = new JPanel();
  pCombo.setLayout(new FlowLayout());
  Presets combo = new Presets();
  combo.addChangeListener(new ChangeListener() {
     public void stateChanged(ChangeEvent e) {
        Presets presetcombo = (Presets) e.getSource();
        int tval;
        tval = (int) presetcombo.getValue(ctrlTriggers);
        label.setText(Integer.toString(tval));
        triggers.setValue(tval);
     }
  });

  pCombo.add(combo, BorderLayout.CENTER);
  frame.add(pCombo, BorderLayout.CENTER);
  frame.add(panelTrig, BorderLayout.LINE_START);


  frame.addWindowListener(new WindowAdapter() {
     public void windowClosing(WindowEvent e) {
        System.exit(0);
     }
  });

  setDefaultCloseOperation(DISPOSE_ON_CLOSE);
  frame.show();
}

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

Triggers.class This class is JPanel where is 4 JButton and ‘LED like image’

public class Triggers extends JPanel
    implements ActionListener, ItemListener {

public Triggers(String s[], String name) {

  JPanel panel = new JPanel(new BorderLayout());
  this.value = Integer.parseInt(s[selected]);

  for (int i = 0; i < s.length; i++) {


     ImageIcon cup = new ImageIcon();
     button[i] = new JButton(z[i], cup);
     button[i].setPreferredSize(new Dimension(70, 25));

     Font font = button[i].getFont();
     button[i].setFont(new Font(font.getFontName(), font.getStyle(), 10));
     button[i].setActionCommand(s[i]);

     if (i == selected) {
        button[i].setSelected(true);
     } else {
        button[i].setSelected(false);
     }
  }



  ButtonGroup group = new ButtonGroup();

  for (int i = 0; i < s.length; i++) {
     group.add(button[i]);
     button[i].addActionListener(this);
     button[i].addItemListener(this);

  }



  diody = new JLabel(createImageIcon("/resources/diody/"
          + this.value
          + ".png"));


  diody.setPreferredSize(new Dimension(20, 100));

  JPanel triggs = new JPanel(new FlowLayout());
 triggs.setPreferredSize(new Dimension(80, 120));

  for (int i = 0; i < s.length; i++) {
     triggs.add(button[i]);
  }

  panel.add(triggs, BorderLayout.LINE_START);
  panel.add(diody, BorderLayout.LINE_END);
  add(panel);


}

public void actionPerformed(ActionEvent e) {

  cmd = e.getActionCommand();
  diody.setIcon(createImageIcon("/resources/diody/"
          + cmd
          + ".png"));



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

     setValue(1);

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

     setValue(2);

  } else if (cmd.equals("3")) {

     setValue(3);

  } else if (cmd.equals("4")) {

     setValue(4);
  }
}

public static ImageIcon createImageIcon(String path) {
  java.net.URL imgURL = Triggers.class.getResource(path);
  if (imgURL != null) {
     return new ImageIcon(imgURL);
  } else {
     System.err.println("Couldn't find file: " + path);
     return null;
  }
}

public int setController() {
  return value;
}

public void setValue(int k) {

  this.value = k;
  cmd = Integer.toString(this.value);
  repaint();
  fireChangeEvent();
}

public int getValue() {
  return this.value;
}

public void setSel(int k) {
  selected = k;
  repaint();
  fireChangeEvent();
}

public void itemStateChanged(ItemEvent ie) {
  String s = (String) ie.getItem();
}

public void addChangeListener(ChangeListener cl) {
  listenerList.add(ChangeListener.class, cl);

}

public void removeChangeListener(ChangeListener cl) {
  listenerList.remove(ChangeListener.class, cl);
}

protected void fireChangeEvent() {
  Object[] listeners = listenerList.getListenerList();
  for (int i = listeners.length - 2; i >= 0; i -= 2) {
     if (listeners[i] == ChangeListener.class) {
        if (changeEvent == null) {
           changeEvent = new ChangeEvent(this);
        }
        ((ChangeListener) listeners[i + 1]).stateChanged(changeEvent);
     }
  }
}
private ChangeEvent changeEvent = null;
private EventListenerList listenerList = new EventListenerList();
private JLabel diody;
private int x = 1;
private int y = 4;
private JButton button[] = new JButton[y];
double border = 4;
double vborder = 1;
int controller[] = new int[4];
String z[] = {"1", "2", "3", "4"};
private int selected;
private int value;
private String cmd;
}

class Presets Here is JCombobox.

public class Presets extends JPanel
       implements ActionListener {
  private int value;
  private int[] ctrlIdx = new int[27];
  private int controller;
  private ChangeEvent changeEvent = null;
  private EventListenerList listenerList = new EventListenerList();
  private JLabel label;
  private String[][] presets = {
     {"0", "3"},
     {"1", "2"},
     {"2", "3"},
     {"3", "1"},
     {"4", "4"},
     {"5", "2"},};
  String[] ctrlName = {"preset 1 (value 3)", "preset 2 (value 2)", "preset 3 (value 3)", "preset 4 (value 1)", "preset 5 (value 4)", "preset 5 (value 2)"};

  public Presets() {


     JPanel panel = new JPanel();
     panel.setLayout(new BorderLayout());
     panel.setPreferredSize(new Dimension(600, 30));

     JComboBox combolist = new JComboBox(ctrlName);
     combolist.setSelectedIndex(2);
     combolist.addActionListener(this);

     combolist.setPreferredSize(new Dimension(300, 30));
     label = new JLabel();
     label.setFont(label.getFont().deriveFont(Font.ITALIC));
     label.setHorizontalAlignment(JLabel.CENTER);
     int indeks = combolist.getSelectedIndex();
     updateLabel(ctrlName[combolist.getSelectedIndex()], indeks);

     label.setBorder(BorderFactory.createEmptyBorder(10, 0, 0, 0));
     label.setPreferredSize(new Dimension(300, 30));


     panel.add(combolist, "East");
     add(panel);
     setPreferredSize(new Dimension(600, 40));

  }

  public void setSelectedItem(int a) {
  }

  public void setValue(int c, int v) {

     controller = c;
     value = v;
     ctrlIdx[controller] = value;

     repaint();
     fireChangeEvent();

  }

  public int getController() {
     return controller;
  }

  public int getValue(int c) {
     int w = (int) ctrlIdx[c];
     return (int) w;
  }

  public void actionPerformed(ActionEvent e) {
     JComboBox cb = (JComboBox) e.getSource();
     String pres = (String) cb.getSelectedItem();
     int indeks = cb.getSelectedIndex();
     updateLabel(pres, indeks);



     for (int i = 0; i < ctrlName.length; i++) {
        for (int j = 0; j < 2; j++) {

           setValue(j, Integer.parseInt(presets[indeks][j]));
        }
     }


  }

  protected void updateLabel(String name, int ii) {

     label.setToolTipText("A drawing of a " + name.toLowerCase());

  }

  protected static ImageIcon createImageIcon(String path) {
     java.net.URL imgURL = Presets.class.getResource(path);
     if (imgURL != null) {
        return new ImageIcon(imgURL);
     } else {
        System.err.println("Couldn't find file: " + path);
        return null;
     }
  }

  public void addChangeListener(ChangeListener cl) {
     listenerList.add(ChangeListener.class, cl);
  }

  public void removeChangeListener(ChangeListener cl) {
     listenerList.remove(ChangeListener.class, cl);
  }

  protected void fireChangeEvent() {

     Object[] listeners = listenerList.getListenerList();

     for (int i = listeners.length - 2; i >= 0; i -= 2) {
        if (listeners[i] == ChangeListener.class) {

           if (changeEvent == null) {
              changeEvent = new ChangeEvent(this);
           }
           ((ChangeListener) listeners[i + 1]).stateChanged(changeEvent);
        }
     }
  }

}

Could someone help me, what am I doing wrong?

Answer 1

Your image is only begin loaded in the actionPerformed method of your Triggers class, which means when you call setValue in response to the stateChanged event thrown by the Presets class, no new image is begin loaded.

Move your image loading logic so it is either in the setValue method or triggered by the setValue method