Using an if statement to test if JTextField is an integer

Question

I want my program to be able to tell if what is inside my two JTextFields is an integer or a String.

CODE

          public void actionP         


        

Answer 1

You can process the key event in the action method also. Try this

First make a JTextField

JTextField j=new JTextField();

Then add KeyListner to this JTextField as

    j.addKeyListener(new KeyListener() {

        @Override
        public void keyTyped(KeyEvent arg0) {
            // TODO Auto-generated method stub

        }

        @Override
        public void keyReleased(KeyEvent arg0) {
            // TODO Auto-generated method stub
            if(arg0.getKeyCode()>57 || arg0.getKeyCode()<48) {
                    //your error message and other handling code here
                JOptionPane.showMessageDialog(PatentFrame, "Only integer allowed", "Message title",JOptionPane.ERROR_MESSAGE);
            }

        }

        @Override
        public void keyPressed(KeyEvent arg0) {
            // TODO Auto-generated method stub

        }
    });

48 is ASCII code for 0 and 57 is ASCII code for 9. You can also ignore virtual keys like shift. See ASCII chart