jcombobox

How to make one item in a combobox unselectable because I need to separate items in a combobox with a sub-topic . And is it possible to modify the font of that particular item individually? jComboBox_btech_course.setFont(new java.awt.Font("Tahoma", 0, 14)); jComboBox_btech_course.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "Select Course" })); jComboBox_btech_course.setName(""); private class theHandler implements ActionListener { public void actionPerformed(ActionEvent evt) { //BTech courses if(jComboBox_mtech_dept.getSelectedItem().equals("Civil Engineering")) { jComboBox

Is there an easy way to check if an item already exists in a JComboBox besides iterating through the latter? Here's what I want to do: Item item = ...; boolean exists = false; for (int index = 0; index < myComboBox.getItemCount() && !exists; index++) { if (item.equals(myComboBox.getItemAt(index)) { exists = true; } } if (!exists) { myComboBox.addItem(item); } Thanks! Use a DefaultComboBoxModel and call getIndexOf(item) to check if an item already exists. This method will return -1 if the item does not exist. Here is some sample code: DefaultComboBoxModel model = new DefaultComboBoxModel(new

I want to have a JCombobox in my Swing application, which shows the title when nothing is selected. Something like this: COUNTRY ▼ Spain Germany Ireland I want "COUNTRY" to show when the selected index is -1 and thus, the user wouldn't be able to select it. I tried to put it on the first slot and then overriding the ListCellRenderer so the first element appears greyed out, and handling the events so when trying to select the "title", it selects the first actual element, but I think this is a dirty approach. Could you lend me a hand? Overriding the ListCellRenderer is a good approach, but you

I need to remove all items from the combo box int itemCount = combo.getItemCount(); for(int i=0;i<itemCount;i++){ combo.removeItemAt(0); } This code will remove all items except the last one. It gives a NullPointerException. How to fix that? The code in the question would normally work. However, it looks like a threading issue. Another thread may be messing with the items. However, I sugeest you should better use the removeAllItems(); method: combo.removeAllItems(); How about JComboBox.removeAllItems() ? Asad In second line: combo.removeItemAt(0) ; I think instead of 0 it should be i . do it