🚀 go-pugleaf

"Ant�nio Ferreira" <antonio.ferreira@artesis.co.pt> wrote:

>      public void focusLost(FocusEvent e) {
>        int k;
>
>          try {
>            k = Integer.parseInt(jTextField1.getText());
>            if (k < 1) {
>              JOptionPane.showMessageDialog(null,
>              "You must enter a value greater than zero",
>              "Atention",
>              JOptionPane.WARNING_MESSAGE);
>              jTextField1.requestFocus();
>            }
>          }catch (NumberFormatException excp) {
>            System.out.println(excp.getMessage());
>            JOptionPane.showMessageDialog(null,
>            "You must enter a numeric value.",
>            "Atention",
>            JOptionPane.WARNING_MESSAGE);
>            jTextField1.requestFocus();
>          }
>      }
>    });
>
>  It always executes twice the appropiate showMessageDialog.
>  Can anyone explain this strange behavior.

upon leaving your text field you get a FOCUS_LOST event. 
In case your validation fails you pop up a modal dialog and 
reset the focus - that triggers a FOCUS_GAINED with the same 
validation ...

you might want to look into javax.swing.InputVerifier and 
JComponent.setInputVerifier instead.

Torsten