JSpinners as JTable cells - a solution

From:
"Rexx Magnus" <trashcan@uk2.net>
Newsgroups:
comp.lang.java.programmer
Date:
Mon, 29 Sep 2008 12:49:26 +0100
Message-ID:
<op.uh8q4od5p9vcmo@macmini.local>
I've been writing an application for the past several weeks that has a =

JTable that uses JSpinners in one column.
I discovered that I was having problems with the TableModel not updating=
  =

whenever a spinner was edited using only the buttons.
Editing with the text field was not a problem - but if you changed a val=
ue =

using the buttons, you had to click in a different cell of the table =

before the model would update.
Evidently, this was a focus problem. JSpinner buttons do not ordinarily =
 =

seem to get focus within a table - the text part can, but the buttons =

don't.

After following numerous posts on forums etc. I stumbled across one =

suggestion to use a custom UI for the spinner - however, this relied on =
 =

the plaf.basic look and feel, which means that if you change the UI in =

order to add focuslisteners as you build it, the buttons may become a =

different look and feel whilst you edit the values.
This wasn't very nice on the Mac, I can tell you!

I didn't really have much of a clue as to what I was doing - but I =

definately didn't want to rebuild the UI from scratch, so I dug down int=
o =

the JSpinner's component list and applied focuslisteners to each. This =

appears to fix the problem completely - something which no other solutio=
n =

on the net had seemed to do without requiring a total program rewrite.

  public class SpinnerEditor extends AbstractCellEditor
             implements TableCellEditor {

         final JSpinner spinner;
         private JTable currentTable;
         private int selectedRow;
         private int selectedColumn;
         // Initializes the spinner.
         public SpinnerEditor(int min, int max) {
             spinner = new JSpinner(new SpinnerNumberModel(min, min, m=
ax, =

1));
             spinner.setFocusable(true);//This alone does not fix the is=
sue

             //List all of the components and make them focusable
             //then add an empty focuslistener to each
             for(Component tmpComponent:spinner.getComponents()){
                 tmpComponent.setFocusable(true);
                 tmpComponent.addFocusListener(new FocusAdapter(){
                 @Override
                 public void focusLost(FocusEvent fe){
                 }});
             }
         }

         public Component getTableCellEditorComponent(JTable table, Obje=
ct =

value,
                 boolean isSelected, int row, int column) {
             spinner.setValue(value);
             currentTable = table;
             selectedRow = row;
             selectedColumn = column;
             return spinner;
         }

         public Object getCellEditorValue() {
             return spinner.getValue();
         }
     }

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