How to add the Jpanel to the Frame created

Question

I have created a class named Frame which simply creates a frame:

package panels;

public class Frame extends prog 
{

    public Frame() {


        JFrame myFrame = new JFrame();  

        myFrame.setLayout( new FlowLayout() );

        myFrame.setTitle("GUI Demo - ISTE-121");
        myFrame.pack();
        myFrame.setLocation(600,300);
        myFrame.setSize(400,200);
        myFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        myFrame.setVisible(true);



    }

}

Then, I have added that frame to the main():

package panels;

public class prog {

    public static void main(String args[]) {
        Frame first = new Frame();
    }
}

I have created a class named panels and want to add this to class Frame. How should I do that?

The subclass is as follows:

public class panels extends Frame {

       final JTextField items;
       final JTextField number;
       final JTextField cost;
       final JTextField amount;


    public panels()
    {


        JPanel order = new JPanel();
          order.setLayout(new GridLayout(5,5,2,2));


          order.add(new JLabel("Item no:", SwingConstants.RIGHT));
          order.add(items = new JTextField(3));

          order.add(new JLabel("Number of:", SwingConstants.RIGHT));
          order.add(number = new JTextField(3));

          order.add(new JLabel("Cost", SwingConstants.RIGHT));
          order.add(cost = new JTextField(3));

          order.add(new JLabel("Amount owed:", SwingConstants.RIGHT));
          order.add(amount = new JTextField(10));
          amount.setEditable(false);

    }
}

Answer 1

Change name of your first class. This class must extend a JFrame, panels class should extend JPanel. You should learn about layout managers, adding panel to container. It's basics of Swing. It's improved code of your program:

class MyFrame extends JFrame {
    public MyFrame() {

        JFrame myFrame = new JFrame();  

        myFrame.setLayout( new FlowLayout() );

        myFrame.add(new panels());
        myFrame.setTitle("GUI Demo - ISTE-121");
        myFrame.pack();
        myFrame.setLocation(600,300);
        myFrame.setSize(400,200);
        myFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        myFrame.setVisible(true);

    }
}

class panels extends JPanel {

   final JTextField items;
   final JTextField number;
   final JTextField cost;
   final JTextField amount;


   public panels() {
      setLayout(new GridLayout(5,5,2,2));

      add(new JLabel("Item no:", SwingConstants.RIGHT));
      add(items = new JTextField(3));

      add(new JLabel("Number of:", SwingConstants.RIGHT));
      add(number = new JTextField(3));

      add(new JLabel("Cost", SwingConstants.RIGHT));
      add(cost = new JTextField(3));

      add(new JLabel("Amount owed:", SwingConstants.RIGHT));
      add(amount = new JTextField(10));
      amount.setEditable(false);

    }
}

public class FrameTest {

    public static void main(String args[]) {
        MyFrame first = new MyFrame();
    }
}