🚀 go-pugleaf

John McGrath  [TeamB] <ng-b@JPMcGrath.net> wrote:
>I presume that you see the dialog twice 
You are correct that the focusLost was called twice; however, I don't know why it was called twice because most java code were generated. I would like to learn the correct way to do this. I use the design tab to create my screen two TextFields and one TextArea, then add the focusLost event for the two TextFields. The focusLost function has a very simple test:
void jTF_src_focusLost(FocusEvent e) {
    JTextField src = (JTextField) e.getSource();
    if (src.getText().length () == 0) {
// I cannot put the showMessageDialog here, because it will
// pop up forever.
      setFocus(src);
      return;
    }
    File f = new File(src.getText());
    if (f.canRead()) {
      return;
    } else {
      JOptionPane.showMessageDialog(ArchUIFrame.this, "Source file [" + src.getText() + "] is not readable or does not exist.",
"Error", JOptionPane.ERROR_MESSAGE);
// if I removed the src.setText(""), then the dialog box pops 
// forever.
      src.setText("");
// if I only have the src.requestFocus(), then the cursor will
// not stay in this field.
      Runnable r = new Runnable() {
          public void run() { jTF_src.requestFocus(); }
      };
      SwingUtilities.invokeLater(r);
      return;
    }
}

I steped through the code, and it showed me the following code sequences: TextField1.focusLost -> processWindowEvent -> TextField1.focusLost.