Java Swing: Get text value from JOptionPane

Question

I'd like to create a new window which is used in POS system. The user input is for an amount of money the customer has and the window has to display the exchange amount. I'm new with JOptionPane feature (I have been using JAVAFX and it's different).

This is my code:

public static void main(String[] argv) throws Exception {
    String newline = System.getProperty("line.separator");
    int cost = 100;
    int amount = Integer.parseInt(JOptionPane.getText()) // this is wrong! This needs to come     from user input box in the same window.
    JFrame frame = new JFrame();
    String message = "Enter the amount of money"+newline+"The exchange money is: "+amount-cost;
    String text = JOptionPane.showInputDialog(frame, message);
    if (text == null) {
      // User clicked cancel
}

Is there any suggestion?

Answer 1

use InputDialog for get userinput

public static void main(String[] argv) throws Exception {
      //JFrame frame = new JFrame();
      //frame.setVisible(true);
      int cost = 100;
      JLabel l=new JLabel("The exchange money is");

      JPanel p=new JPanel(new GridLayout(1, 2, 10, 10));
      p.setPreferredSize(new Dimension(400, 50));
      JTextField t=new JTextField("Enter the amount of money");
      t.addKeyListener(new java.awt.event.KeyAdapter() {
        public void keyReleased(java.awt.event.KeyEvent evt) {
            try{
            int amount=Integer.parseInt(t.getText());
            l.setText("The exchange money is: \n" + (amount - cost));
            }catch(Exception ex){
               // ex.printStackTrace();
            }
        }
      });
      p.add(t);
      p.add(l);

    int option = JOptionPane.showConfirmDialog(null,p,"JOptionPane Example : ",JOptionPane.OK_CANCEL_OPTION,JOptionPane.PLAIN_MESSAGE);
    if(option==0){
        System.out.println("ok clicked");
    }else{
        System.out.println("cancel clicked");
    }
}