Drawing a line on a canvas?

Here is my code so far:

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;

import javax.swing.*;

public class Paint extends JFrame {
	private static PCanvas canvas = new PCanvas();

	

  public Paint() {

    // Create a panel to group three buttons
    JPanel p1 = new JPanel(new GridLayout (1, 3));
    
    JButton jbtClear = new JButton("Clear");
    JButton jbtFG = new JButton("FG");
    JButton jbtBG = new JButton("BG");

    jbtClear.setToolTipText("Clears Canvas");
    jbtFG.setToolTipText("This changes Foreground Color");
    jbtBG.setToolTipText("This changes Background Color");
    
    p1.add(jbtClear);
    p1.add(jbtFG);
    p1.add(jbtBG);
    
    // Create a panel to group two labels
    JPanel p2 = new JPanel(new GridLayout (1, 4));

    JButton jbtLine = new JButton("Line");
    JButton jbtPolyLine = new JButton("PolyLine");   
    JButton jbtOval = new JButton("Oval");   
    JButton jbtFilledOval = new JButton("FilledOval");
    
    jbtLine.setToolTipText("Creates a line");
    jbtPolyLine.setToolTipText("Creates a Poly Line");
    jbtOval.setToolTipText("Creates an oval");
    jbtFilledOval.setToolTipText("Creates a filled oval");


    p2.add(jbtLine);
    
    	jbtLine.addActionListener(new ActionListener(){
    		public void actionPerformed(ActionEvent e){
    			canvas.line();
    		}
    		});
    	
    
    p2.add(jbtPolyLine);    
    p2.add(jbtOval);    
    p2.add(jbtFilledOval);

    
    // Create a panel to group two labels
    JPanel p3 = new JPanel(new GridLayout (1, 4));
    
    JButton jbtRectangle = new JButton("Rectangle");
    JButton jbtFilledRectangle = new JButton("FilledRectangle");    
    JButton jbtRoundRectangle = new JButton("RoundRectangle");   
    JButton jbtFilledRoundRectangle = new JButton("FilledRoundRectangle");
    
    jbtRectangle.setToolTipText("Creates a Rectangle");
    jbtFilledRectangle.setToolTipText("Creates a Filled Rectangle");
    jbtRoundRectangle.setToolTipText("Creates a round rectangle");
    jbtFilledRoundRectangle.setToolTipText("Creates a filled round rectangle");

    p3.add(jbtRectangle);
    p3.add(jbtFilledRectangle);    
    p3.add(jbtRoundRectangle);   
    p3.add(jbtFilledRoundRectangle);

    // Add two panels to the frame
 
    setLayout(new GridLayout(4, 1, 1, 1));
    add(canvas, BorderLayout.NORTH);
    add(p1);
    add(p2);
    add(p3);
    
    
  }



  public static void main(String[] args) {

    // Create a frame and set its properties
    JFrame frame = new Paint();

    frame.setTitle("TestSwingCommonFeatures");

    frame.setSize(700, 700);

    frame.setLocationRelativeTo(null); // Center the frame
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    frame.setVisible(true);
  }
  
  public static class PCanvas extends JPanel {
	  
	  private int x = 0;
	  private int y = 0;
	    public void line(){
	    	addMouseMotionListener(new MouseMotionAdapter(){
	    		public void mouseDragged(MouseEvent e){
	    		
	    			x = e.getX();
	    			y = e.getY();
	    			System.out.println(x + y);
	    			repaint();
	    		}
	    	});
	    	
	    }

		/** Repaint the line */
	    protected void paintComponent(Graphics g) {
	      super.paintComponent(g);
	      
	    }
	  }

}

For now, I just want to foucs on drawing a line by clicking on the line button and dragging the mouse to draw the line on the canvas. I'm a beginner at this, can someone help me. I believe what do I do so when I click on the canvas and drag the mouse, a line comes out and stays on it? Thanks in advance!