how to make JDialog with checkboxes

Question

I am writing a Java program and I ran into a problem. I have an ArrayList<JCheckBox> and I want to show some dialog window with these checkboxes, so I can choose some of them and I want another ArrayList<> of the selected objects as an outcome after closing that dialog. I think I can get results by adding ActionListener to those checkboxes, but I don´t know how to pass that ArrayList<JCheckBox> to the dialog window..

So far I tried something like this:

ArrayList<JCheckBox> al = new ArrayList<JCheckBox>();
for (MyClass mc : sr.getFields().values())
{
    JCheckBox box = new JCheckBox(mc.getType());
    al.add(box);
}
JOptionPane.showConfirmDialog(null, al);

If I try to print the text in the checkbox, it is ok, but the dialog shows only a long line of some text that does not make any sense..

So, is there a way how to do that?

Thanks in advance..

Answer 1

The showConfirmDialog method has to interpret the message object in order to render it correctly and it doesn't know how to interpret an ArrayList , you have to add all your elements to an JPanel eg:

JPanel al = new JPanel();
for (MyClass mc : sr.getFields().values()){
    JCheckBox box = new JCheckBox(mc.getType());
    al.add(box);
}
JOptionPane.showConfirmDialog(null, al);

or an Object[] eg:

ArrayList<JCheckBox> al = new ArrayList<JCheckBox>();
for (MyClass mc : sr.getFields().values()){
    JCheckBox box = new JCheckBox(mc.getType());
    al.add(box);
}
Object[] obj = (Object[]) al.toArray(new Object[al.size()]);
JOptionPane.showConfirmDialog(ui, obj);