Fix JComboBox width
I have a JComboBox with some options. When I make a selection at another component, I'm changing JComboBox contents. First I call the removeAllItems() method, and then I add one by one the Strings I need now.
The problem is, by default I had some options, and one of them was the larger text, so JComboBox got the width it needed to show that option correctly. When I change the JComboBox contents, that text option is gone, and now a smaller text is giving the width to the JComboBox, so when I change contents it gets smaller.
My first approach was calling myComboBox.setPreferredSize(myComboBox.getSize()) and then its dimensions are fixed, but not correctly: it gets a bit smaller in height and width. I think it is because I'm using Nimbus Look&Feel, and the dimensions I'm getting from the getSize() method are the ones given by the Java default Look%Feel.
I also tried myCombo.setPreferredSize(new Dimension(myCombo.getHeight(), myCombo.getWidth())) with same results.
How can I approach this problem?
I add a code example of how I'm using the Layout:
private String[] comboEventDOutputStrings = { "Run", "Stop", "Pause", "Conditioning time", "Deposition time", "Equilibration time", "Measurement time"};
private String[] comboEventDInputStrings = { "Run", "Stop", "Pause"};
// The first String array is the default set of values. It's obvious that the JComboBox will get smaller
// when I change to the second array of contents
//...
JPanel pane = new JPanel(new GridBagLayout());
JPanel jPanelExterno = new JPanel(new GridBagLayout());
GridBagConstraints cExterna = new GridBagConstraints();
GridBagConstraints c = new GridBagConstraints();
Border loweredetched = BorderFactory.createEtchedBorder(EtchedBorder.LOWERED);
jPanelExterno.setBorder(loweredetched);
jPanelExterno.setName("");
cExterna.fill = GridBagConstraints.BOTH;
cExterna.anchor = GridBagConstraints.NORTH;
cExterna.gridx = 0;
cExterna.gridy = 0;
cExterna.insets = new Insets(10,10,5,5);
JPanel jPanel1 = new JPanel(new GridBagLayout());
jPanel1.setBorder(loweredetched);
jPanel1.setName("PIO 1");
jCheckBox1 = new JCheckBox("Enable");
jCheckBox1.setSelected(false);
jCheckBox1.setName("1");
jCheckBox1.addActionListener(new PIOCheckListener());
c.fill = GridBagConstraints.BOTH;
c.anchor = GridBagConstraints.NORTH;
c.gridx = 0;
c.gridy = 0;
c.insets = new Insets(10,5,10,10);
jPanel1.add(jCheckBox1, c);
c.gridy++;
c.insets = new Insets(5,10,5,5);
JLabel label1 = new JLabel("IO Type");
jPanel1.add(label1, c);
c.gridx++;
c.insets = new Insets(5,5,5,10);
combo1 = new JComboBox(comboIOTypeStrings);
combo1.setEnabled(false);
combo1.setSelectedIndex(0);
combo1.setName("1");
combo1.addActionListener (new PIOComboListener());
jPanel1.add(combo1, c);
c.gridy++;
c.insets = new Insets(5,10,5,5);
c.gridx=0;
JLabel label2 = new JLabel("Active level");
jPanel1.add(label2, c);
c.gridx++;
c.insets = new Insets(5,5,5,10);
combo2 = new JComboBox(comboActiveLevelStrings);
combo2.setEnabled(false);
combo2.setSelectedIndex(0);
jPanel1.add(combo2, c);
c.gridy++;
c.insets = new Insets(5,10,5,5);
c.gridx=0;
JLabel label3 = new JLabel("Event");
jPanel1.add(label3, c);
c.gridx++;
c.insets = new Insets(5,5,10,10);
combo3 = new JComboBox(comboEventDOutputStrings);
combo3.setEnabled(false);
combo3.setSelectedIndex(0);
jPanel1.add(combo3, c);
c.gridy++;
c.insets = new Insets(5,10,5,5);
c.gridx=0;
JLabel label4 = new JLabel("Node");
jPanel1.add(label4, c);
c.gridx++;
c.insets = new Insets(5,5,10,10);
combo4 = new JComboBox(comboNodeStrings);
combo4.setEnabled(false);
combo4.setSelectedIndex(0);
jPanel1.add(combo4, c);
jPanelExterno.add(jPanel1, cExterna);
pioDialog.add(pane);
pioDialog.pack();
pioDialog.setLocationRelativeTo(null);
pioDialog.setVisible(true);
//...
}
class PIOComboListener implements ActionListener{
@Override
public void actionPerformed(ActionEvent a) {
JComboBox cb = (JComboBox)a.getSource();
JComboBox target1 = null;
JComboBox target2 = null;
JComboBox target3 = null;
switch(Integer.parseInt(cb.getName())){
case 1:
target1 = combo2;
target2 = combo3;
target3 = combo4;
break;
default:
Register.debug("PIODialog error: No target for comboBoxes");
break;
}
if(cb.getSelectedIndex()==2){ //Analog input
target1.setEnabled(false);
target2.setEnabled(false);
target3.setEnabled(false);
}
else{
target1.setEnabled(true);
target2.setEnabled(true);
target3.setEnabled(true);
target2.removeAllItems();
if(cb.getSelectedIndex()==0){
for(int i=0; i<comboEventDOutputStrings.length; i++)
target2.addItem(comboEventDOutputStrings[i]);
} else {
for(int i=0; i<comboEventDInputStrings.length; i++)
target2.addItem(comboEventDInputStrings[i]);
}
}
}
}
It's basically a GridBagLayout with 6 JPanel with a new GridBagLayout for each one of them. I just wrote jPanel1 here to simplify things. I hope it is not very messy.
Answer
Finally I found an easy solution:
jComboBox1.setPrototypeDisplayValue("XXXXXXXXXXXXXXXXXX");
And works perfect for what I wanted