HELP! Problem with Listener

[Pat Watson]

Hello Guys,
I am having a problem with my button. When I select one of the radio buttons and then click the button nothing happens so it must be something with my listener.

Moreover, if I want to use this same file but use paint and repaint to draw a rectangle (I know how to use paint() but I constantly get confused as to what goes where) what would I do?
Can I do

	if(circle.isSelected())
				repaint();   
			if(rectangle.isSelected())
				repaint(); 
public void paint(Graphics g){
g.drawRect();
}

Here are my codes

package Project2;

import java.awt.*;

import javax.swing.JFrame;

public class mainFrame extends JFrame{

	private int frameWidth;
	private int frameHeight;
	
	
	// constructor------------------------------------------------------------
	public mainFrame(String title, int w, int h) {
		createMyFrame(title,w,h);
		
	}// end constructor-------------------------------------------------------
	
	/************************************************************************/
	// method to create a myFrame object
	private void createMyFrame(String t, int w, int h) {
		frameWidth = w * 96;
		frameHeight = w * 96;
		// Title
		setTitle(t);
		// Size
		setSize(new Dimension(frameWidth, frameHeight));
		
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		// Center my frame on my screen
		setLocationRelativeTo(null);
		// make the frame visible
		//pack();
		setVisible(true);
	}// end createMyFrame() method
	
} // end myFrame class

next code

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.TitledBorder;



@SuppressWarnings("serial")
public class ShapeFrameGUI extends mainFrame{
	
	// Initialize Component Controls
	Label lblSide1, lblSide2, lblSide3,instr;
	TextField txtSide1, txtSide2, txtSide3;
	JRadioButton circle,square,triangle,rectangle,sphere,cube,cone,cylinder,torus;
	ButtonGroup cbg;
	Button bttnPaintShape;
	JPanel panelNorth = new JPanel();
	JPanel panelSouth = new JPanel();
	ButtonModel bm;
	
	String msg = "";
	String str = "";
	
	buttonHandler bh;
	
	// Constructor************************************************************
	public ShapeFrameGUI(String title, int w, int h) {
		super(title, w, h);
		customizeFrame();
		setRBComponents();
		setSouthPanel();
		// Add item listeners
		bttnPaintShape.addActionListener(bh);

	} // End Constructor*******************************************************
	
	private void customizeFrame() {
		// Set up margins all around
		getRootPane().setBorder(BorderFactory.createMatteBorder(
				15, 15, 15, 15, getBackground()));
		// Create main Container to hold all of my panels
		this.setLayout(new BorderLayout(10, 8));
		
	}// end customizeFrame() method
	
	// Method to set my radio button and add them to the panel
	private void setRBComponents() {
		panelNorth.setLayout(new GridLayout(2, 5, 5, 5));
		panelNorth.setBorder(BorderFactory.createTitledBorder(
				BorderFactory.createMatteBorder(1,1,1,1,Color.BLACK),
				"Select a shape from the list", TitledBorder.LEFT, TitledBorder.TOP));
		// Create a check box group
		cbg = new ButtonGroup();

		// Create Controls
		circle = new JRadioButton("Circle",true);
		square = new JRadioButton("Square",false);
		triangle = new JRadioButton("Triangle",false);
		rectangle = new JRadioButton("Rectangle",false);
		sphere = new JRadioButton("Sphere",false);
		cube = new JRadioButton("Cube",false);
		cone = new JRadioButton("Cone",false);
		cylinder = new JRadioButton("Cylinder",false);
		torus = new JRadioButton("Torus", false);
		
		cbg.add(circle); cbg.add(square);
		cbg.add(triangle); cbg.add(rectangle);
		cbg.add(sphere); cbg.add(cube);
		cbg.add(cone); cbg.add(cylinder);
		cbg.add(torus);
		
		// add check boxes to the north panel
		panelNorth.add(circle); panelNorth.add(square);
		panelNorth.add(triangle); panelNorth.add(rectangle);
		panelNorth.add(sphere); panelNorth.add(cube);
		panelNorth.add(cone); panelNorth.add(cylinder);
		panelNorth.add(torus);
		
		add(panelNorth,BorderLayout.NORTH);
	}// end setRBComponents() method
	
	private void setSouthPanel() {
		panelSouth.setLayout(new FlowLayout());
		bttnPaintShape = new Button("Paint Shape");
		panelSouth.add(bttnPaintShape);
		add(panelSouth,BorderLayout.SOUTH);
	}
	
	// Listener handler
	class buttonHandler implements ActionListener{
		public void actionPerformed(ActionEvent ae) {
			if(circle.isSelected())
				JOptionPane.showMessageDialog(null, "This is a circle");   
			if(rectangle.isSelected())
				JOptionPane.showMessageDialog(null, "This is a rectangle"); 
			if(square.isSelected())
				JOptionPane.showMessageDialog(null, "This is a square"); 
			if(triangle.isSelected())
				JOptionPane.showMessageDialog(null, "This is a triangle"); 
			if(sphere.isSelected())
				JOptionPane.showMessageDialog(null, "This is a sphere"); 
			if(cube.isSelected())
				JOptionPane.showMessageDialog(null, "This is a cube");
			if(cone.isSelected())
				JOptionPane.showMessageDialog(null, "This is a cone"); 
			if(cylinder.isSelected())
				JOptionPane.showMessageDialog(null, "This is a cylinder"); 
			if(torus.isSelected())
				JOptionPane.showMessageDialog(null, "This is a torus"); 
		}
	}


	
	/************************************************************************/
	// main() method
	public static void main(String[] args) {
		String title = "Project 2 - Shape GUI";
		int w = 7;
		int h = 5;
		new ShapeFrameGUI(title,w,h);

	}

[Pat Watson]

It works now. I was able to fix it BUT now I am having a problem with the paint() and repaint()
If I want the image to be painted based on first the selection and second clicking the button, How do I go about it?

[Matthew Bendford]

couple of advises:
don't extend from JFrame unless you alter its base behaviour - your code isn't a JFrame, it uses one
when dealing with swing make sure to override paintComponent() instead of paint()
I didn't look at your listeners, but be aware of how to deal with swings thrwading policy

[Pat Watson]

Matthew Bendford wrote:couple of advises:
don't extend from JFrame unless you alter its base behaviour - your code isn't a JFrame, it uses one
when dealing with swing make sure to override paintComponent() instead of paint()
I didn't look at your listeners, but be aware of how to deal with swings thrwading policy

Thank you for the response. I am overriding the paintComponent() but it is not working. Here is what I have so far:

	// Listener handler
	class buttonHandler implements ActionListener{
		public void actionPerformed(ActionEvent ae) {
			repaint();
			
		}
	}
	
	protected void paintComponent(Graphics g) {
		Graphics2D g2 = (Graphics2D) g.create();
		
		if(circle.isSelected()) {
			g2.fillRect(192, 240, 2, 1);
		}else if(square.isSelected()) {
			g2.fillOval(192, 240, 1, 1);
		}
	}

[Campbell Ritchie]

Matthew Bendford wrote:. . . override paintComponent() instead of paint() . . .

And give it protected access, not public. There is a format for the first line of that method which you should use so as to get the display blanked before you draw anything.@Override protected void paintComponet(Graphics g) {   super.paintComponent(g); }Go through the Java™ Tutorials (I think the 2nd and 3rd sections there sill will be the most useful) and find out what sort of Listener you want. Something like a change listener maybe, but I am not sure.
I don't like lots of ifs. I am afraid it doesn't look object‑oriented. You can probably write

myButtonGroup.addChangeListener(evt ->
      {
         JRadioButton activeButton = myButtonGroup.getActivated();
         String shapeName = activeButton.getText();
         // ...
      });

I have probably got all the method names wrong, so you will have to check carefully. I presume you are aware of the XXXAdapter classes in the java.awt.event package? I don't think they are applicable to change listeners, because that is a Functional Interface even without showing that annotation.

You can probably remove most of those comments because they don't tell you anything that isn't obvious from looking at the code.
[edit]Correct some spelling errors

[Pat Watson]

Campbell Ritchie wrote:Moving to our GUIs forum

I am almost there but now the drawing is showing under my north nested panel. when I am drawing the rectangle I specify the X and Y but it is not taking. I tried to add a center nested panel but now it is painting under it. Here is my code so far

/*
 * File: ShapesPanel.java
 * Author: Arlette Watson
 * Date: February 9, 2021
 * Description: This class will create the Shapes Panel class
 * subclass to the mainPanel class, and will define all Panels
 */
package Project2;


import javax.swing.*;
import javax.swing.border.TitledBorder;

import Project1.Circle;

import java.awt.*;
import java.awt.event.*;

public class ShapesPanels extends JPanel{
	
	JRadioButton circle,square,triangle,rectangle,sphere,cube,cone,cylinder,torus;
	ButtonGroup cbg;
	Button bttnPaintShape;
	JPanel panelNorth = new JPanel();
	JPanel panelSouth = new JPanel();
	JPanel centerDrawPanel = new JPanel();
	

	buttonHandler bh = new buttonHandler();
	
	// Constructor************************************************************
	public ShapesPanels() {
		super();
		setLayout(new BorderLayout(10, 8));
		add(getPanelNorth(),BorderLayout.NORTH);
		add(getPanelSouth(),BorderLayout.SOUTH);
		bttnPaintShape.addActionListener(bh);
		add(getCenterDrawPanel(),BorderLayout.CENTER);

		
	}// end constructor*******************************************************
	
	public JPanel getPanelNorth() {
		panelNorth.setLayout(new GridLayout(2, 5, 5, 5));
		panelNorth.setBorder(BorderFactory.createTitledBorder(
				BorderFactory.createMatteBorder(1,1,1,1,Color.BLACK),
				"Select a shape from the list", TitledBorder.LEFT, TitledBorder.TOP));
		// Create a check box group
		cbg = new ButtonGroup();

		// Create Controls
		circle = new JRadioButton("Circle",true);
		square = new JRadioButton("Square");
		triangle = new JRadioButton("Triangle");
		rectangle = new JRadioButton("Rectangle");
		sphere = new JRadioButton("Sphere");
		cube = new JRadioButton("Cube");
		cone = new JRadioButton("Cone");
		cylinder = new JRadioButton("Cylinder");
		torus = new JRadioButton("Torus");
		
		cbg.add(circle); cbg.add(square);
		cbg.add(triangle); cbg.add(rectangle);
		cbg.add(sphere); cbg.add(cube);
		cbg.add(cone); cbg.add(cylinder);
		cbg.add(torus);
		
		// add check boxes to the north panel
		panelNorth.add(circle); panelNorth.add(square);
		panelNorth.add(triangle); panelNorth.add(rectangle);
		panelNorth.add(sphere); panelNorth.add(cube);
		panelNorth.add(cone); panelNorth.add(cylinder);
		panelNorth.add(torus);
		return panelNorth;
	}// end getPanelNorth()
	
	public JPanel getPanelSouth() {
		panelSouth.setLayout(new FlowLayout());
		bttnPaintShape = new Button("Paint Shape");
		panelSouth.add(bttnPaintShape);
		return panelSouth;
	}// end getPanelSouth()
	
	public JPanel getCenterDrawPanel() {
		//centerDrawPanel.setBackground(Color.BLUE);
		return centerDrawPanel;
	}
	
	int txt1, txt2, txt3;
	// Listener handler
	class buttonHandler implements ActionListener{
		public void actionPerformed(ActionEvent ae) {
			repaint();
			
		}
	}
	
	public void paintComponent(Graphics g) {
		super.paintComponent(g);
		if(rectangle.isSelected()) {
			Rectangle2D r = new Rectangle2D(getDim1(), getDim2());
			g.fillRect(288, 288,r.getW(), r.getL()); 
		}
			 
	}// End paintComponent
	
	protected int getDim1() {
		int dim1 = 0;
		String str1 = JOptionPane.showInputDialog("Please ender dimension 1");
		dim1 = Integer.parseInt(str1);
		return dim1;
	}
	
	protected int getDim2() {
		int dim2 = 0;
		String str1 = JOptionPane.showInputDialog("Please ender dimension 1");
		dim2 = Integer.parseInt(str1);
		return dim2;
	}
	

	

}// End ShapesPanels

and here is an image of the GUI with the image underneath it. I don't know what to do at this point

[Norm Radder]

The code does not compile because of missing Rectangle2D class definition.

How can the code be compiled and executed for testing?

[Pat Watson]

Norm Radder wrote:The code does not compile because of missing Rectangle2D class definition.

How can the code be compiled and executed for testing?

The Rectangle2D is defined and I created an object before using the reference. Is that what you mean?
These are my codes

public class TwoDShapes extends Shapes {
	protected int w, l;
	
	public TwoDShapes(int w, int l) {
		this.w = w;
		this.l = l;
	}
	
	public int getW() {
		return w;
	}
	
	public int getL() {
		return l;
	}
}

public class Rectangle2D extends TwoDShapes{
	
	public Rectangle2D(int w, int l) {
		super(w,l);
	}
	
	public int getW() {
		return w;
	}
	
	public int getL() {
		return l;
	}
	

}

[Pat Watson]

Pat Watson wrote:

Norm Radder wrote:The code does not compile because of missing Rectangle2D class definition.

How can the code be compiled and executed for testing?

The Rectangle2D is defined and I created an object before using the reference. Is that what you mean?
These are my codes

public class TwoDShapes extends Shapes {
	protected int w, l;
	
	public TwoDShapes(int w, int l) {
		this.w = w;
		this.l = l;
	}
	
	public int getW() {
		return w;
	}
	
	public int getL() {
		return l;
	}
}

public class Rectangle2D extends TwoDShapes{
	
	public Rectangle2D(int w, int l) {
		super(w,l);
	}
	
	public int getW() {
		return w;
	}
	
	public int getL() {
		return l;
	}
	

}

By the way, I see the red rectangle but it is hidden under the North panel. I specify X and X where I want it to start but  it is not painting in the middle which is my problem
The GUI is attached

[Norm Radder]

Where is the color set?  I the bottom of a rectangle is displaying as red.
Also what was the value of the rectangle's width and height?

Note: Rectangle2D is the name of a java SE class.  It is better if you do NOT give your classes the same names as java SE classes.
What is the need for the Rectangle2D class in the current program?

           // Why this?
           Rectangle2D r = new Rectangle2D(getDim1(), getDim2());
            g.fillRect(288, 288,r.getW(), r.getL()); 

            // Why not this?
            g.fillRect(288, 288, getDim1(), getDim2()); 

I added this to ShapesPanels for testing:

    
    /************************************************************************/
    // main() method
    public static void main(String[] args) {
        String title = "Project 2 - Shape GUI";
        int w = 7;
        int h = 5;
        new ShapesPanels().createMyFrame(title,w,h);      //<<<<<<<
 
    }

    private int frameWidth;
    private int frameHeight;
     
     
     
    /************************************************************************/
    // method to create a myFrame object
    private void createMyFrame(String t, int w, int h) {
        JFrame f = new JFrame();
        frameWidth = w * 96;
        frameHeight = w * 96;
        // Title
        f.setTitle(t);
        // Size
        f.setSize(new Dimension(frameWidth, frameHeight));
         
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        // Center my frame on my screen
        f.setLocationRelativeTo(null);
        // make the frame visible
        //pack();
        f.add(this, BorderLayout.CENTER);                     //<<<<<<<<
        f.setVisible(true);
    }// end createMyFrame() method

[Pat Watson]

Norm Radder wrote:Where is the color set?  I the bottom of a rectangle is displaying as red.
Also what was the value of the rectangle's width and height?

Note: Rectangle2D is the name of a java SE class.  It is better if you do NOT give your classes the same names as java SE classes.
What is the need for the Rectangle2D class in the current program?

           // Why this?
           Rectangle2D r = new Rectangle2D(getDim1(), getDim2());
            g.fillRect(288, 288,r.getW(), r.getL()); 

            // Why not this?
            g.fillRect(288, 288, getDim1(), getDim2()); 

I added this to ShapesPanels for testing:

    
    /************************************************************************/
    // main() method
    public static void main(String[] args) {
        String title = "Project 2 - Shape GUI";
        int w = 7;
        int h = 5;
        new ShapesPanels().createMyFrame(title,w,h);      //<<<<<<<
 
    }

    private int frameWidth;
    private int frameHeight;
     
     
     
    /************************************************************************/
    // method to create a myFrame object
    private void createMyFrame(String t, int w, int h) {
        JFrame f = new JFrame();
        frameWidth = w * 96;
        frameHeight = w * 96;
        // Title
        f.setTitle(t);
        // Size
        f.setSize(new Dimension(frameWidth, frameHeight));
         
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        // Center my frame on my screen
        f.setLocationRelativeTo(null);
        // make the frame visible
        //pack();
        f.add(this, BorderLayout.CENTER);                     //<<<<<<<<
        f.setVisible(true);
    }// end createMyFrame() method

Thank you for the response. We have to create shapes objects within the paintComponent. Expanding from a previous project where we create different Shapes classes
I just realized that the issue is with my main Panel Layout. I have it as a BorderLayout so that I can position one nested panel in the North and the other in the South with the middle used to paint but this is not what is happening here.
I changed the main panel size in between each nested panel to this

setLayout(new BorderLayout(300,600));

and now when I make circle 400, 400 I get the attached. So

g.fillOval(20, 50,400, 400);

. Why is it coming from behind my north panel and is there a way to attach it to a nested center panel?

[Norm Radder]

Please post your current code  that can be compiled and executed for testing.

[Pat Watson]

Norm Radder wrote:Please post your current code  that can be compiled and executed for testing.

I am attaching the files

/*
 * File: ShapesPanel.java
 * Author: Arlette Watson
 * Date: February 9, 2021
 * Description: This class will create the Shapes Panel class
 * subclass to the mainPanel class, and will define all Panels
 */
package Project2;


import javax.swing.*;
import javax.swing.border.TitledBorder;




import java.awt.*;
import java.awt.event.*;

public class ShapesPanels extends JPanel{
	
	JRadioButton circle,square,triangle,rectangle,sphere,cube,cone,cylinder,torus;
	ButtonGroup cbg;
	Button bttnPaintShape;
	JPanel panelNorth = new JPanel();
	JPanel panelSouth = new JPanel();
	JPanel centerDrawPanel = new JPanel();

	buttonHandler bh = new buttonHandler();
	
	// Constructor************************************************************
	public ShapesPanels() {
		super();
		setLayout(new BorderLayout(300,500));
		setPreferredSize(new Dimension(400, 384));
		getPanelNorth();
		getPanelSouth();
		add(panelNorth,BorderLayout.NORTH);
		add(panelSouth,BorderLayout.SOUTH);
		bttnPaintShape.addActionListener(bh);
		add(getCenterDrawPanel(),BorderLayout.CENTER);
		
	}// end constructor*******************************************************
	
		// Create Panel North
	public void getPanelNorth() {
		panelNorth.setLayout(new GridLayout(2, 5, 5, 5));
		panelNorth.setBorder(BorderFactory.createTitledBorder(
				BorderFactory.createMatteBorder(1,1,1,1,Color.BLACK),
				"Select a shape from the list", TitledBorder.LEFT, TitledBorder.TOP));
		// Create a check box group
		cbg = new ButtonGroup();

		// Create Controls
		circle = new JRadioButton("Circle",false);
		square = new JRadioButton("Square");
		triangle = new JRadioButton("Triangle");
		rectangle = new JRadioButton("Rectangle");
		sphere = new JRadioButton("Sphere");
		cube = new JRadioButton("Cube");
		cone = new JRadioButton("Cone");
		cylinder = new JRadioButton("Cylinder");
		torus = new JRadioButton("Torus");
		
		cbg.add(circle); cbg.add(square);
		cbg.add(triangle); cbg.add(rectangle);
		cbg.add(sphere); cbg.add(cube);
		cbg.add(cone); cbg.add(cylinder);
		cbg.add(torus);
		
		// add check boxes to the north panel
		panelNorth.add(circle); panelNorth.add(square);
		panelNorth.add(triangle); panelNorth.add(rectangle);
		panelNorth.add(sphere); panelNorth.add(cube);
		panelNorth.add(cone); panelNorth.add(cylinder);
		panelNorth.add(torus);
		
	}// end getPanelNorth()
	
	public void getPanelSouth() {
		panelSouth.setLayout(new FlowLayout());
		bttnPaintShape = new Button("Paint Shape");
		panelSouth.add(bttnPaintShape);
		
	}// end getPanelSouth()
	
	public JPanel getCenterDrawPanel() {
		//centerDrawPanel.setBackground(Color.BLUE);
		centerDrawPanel.setPreferredSize(new Dimension(384, 384));
		repaint();
		return centerDrawPanel;
	}// end getCenterDrawPanel()
	
	// Listener handler
	class buttonHandler implements ActionListener{
		public void actionPerformed(ActionEvent ae) {
			repaint();
		}
	}
	TwoDShapes r,c,s;
	
	public void paintComponent(Graphics g) {
		super.paintComponent(g);
		setPreferredSize(new Dimension(600, 600));
		if(rectangle.isSelected()) {
			r = new ShapeRectangle(getDim1(), getDim2());
			g.setColor(Color.RED);
			g.fillRect(20, 50,r.getW(), r.getL()); 
		}else if (circle.isSelected()) {
			c = new ShapeCircle(getDim1(), getDim2());
			g.setColor(Color.RED);
			g.fillOval(20, 50,c.getW(), c.getL());
		}else if(square.isSelected()) {
			s = new ShapeSquare(getDim1());
			g.setColor(Color.BLUE);
			g.fillRect(20, 50, s.getW(), s.getW());
		}
			 
	}// End paintComponent
	
	protected int getDim1() {
		int dim1 = 0;
		String str1 = JOptionPane.showInputDialog("Please ender dimension 1");
		dim1 = Integer.parseInt(str1);
		return dim1;
	}
	
	protected int getDim2() {
		int dim2 = 0;
		String str1 = JOptionPane.showInputDialog("Please ender dimension 1");
		dim2 = Integer.parseInt(str1);
		return dim2;
	}
	

	

}// End ShapesPanels

package Project2;

import java.awt.*;
import javax.swing.*;


@SuppressWarnings("serial")
public class ShapeFrameGUI {
	private int frameWidth;
	private int frameHeight;
	
	JFrame f = new JFrame();
	ShapesPanels sp = new ShapesPanels();

	
	// Constructor************************************************************
	public ShapeFrameGUI(String title, int w, int h) {
		createMyFrame(title,w,h);
		customizeFrame();

	} // End Constructor*******************************************************
	
	// method to create a myFrame object
	private void createMyFrame(String t, int w, int h) {
		frameWidth = w * 96;
		frameHeight = w * 96;
		// Title
		f.setTitle(t);
		// Size
		f.setSize(new Dimension(frameWidth, frameHeight));
		
		f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		// Center my frame on my screen
		f.setLocationRelativeTo(null);
		// make the frame visible
		f.setVisible(true);
	}// end createMyFrame() method
	
	/************************************************************************/
	private void customizeFrame() {
		// Set up margins all around
		f.getRootPane().setBorder(BorderFactory.createMatteBorder(
				15, 15, 15, 15, f.getBackground()));
		Container mainContainer = f.getContentPane();
		mainContainer.add(sp);
		// Create main Container to hold all of my panels
		//this.setLayout(new BorderLayout(10, 8));
	}// end customizeFrame() method

	
	/************************************************************************/
	// main() method
	public static void main(String[] args) {
		String title = "Project 2 - Shape GUI - Arlette Watson";
		int w = 7;
		int h = 6;
		new ShapeFrameGUI(title,w,h);

	}

}

package Project2;

import java.awt.*;
import javax.swing.*;
public class Shapes extends JPanel{
	// All shapes must start at point(2,2.5)
	public static final Point p = new Point(96,192);
	
	public int x() {
		return Shapes.p.x;
	}

	public int y() {
		return Shapes.p.y;
	}
	

}

package Project2;

public class TwoDShapes extends Shapes {
	protected int w, l;
	
	public TwoDShapes(int w, int l) {
		this.w = w;
		this.l = l;
	}
	
	public TwoDShapes(int w) {
		this.w = w;
	}
	
	public int getW() {
		return w;
	}
	
	public int getL() {
		return l;
	}
}

package Project2;

public class ShapeRectangle extends TwoDShapes{
	
	public ShapeRectangle(int w, int l) {
		super(w,l);
	}
	
	public int getW() {
		return w;
	}
	
	public int getL() {
		return l;
	}
	

}

[Norm Radder]

The  paintComponent method is in the ShapesPanels class so the drawing coordinates are for that panel.  If you want the drawing to be defined by the coordinates for the centerDrawPanel object, then the code needs to override the paintComponent method for that instance of JPanel.

[salvin francis]

paintComponent which is called during every layout calls getDim1/getDim2 which calls a JOptionPane.showInputDialog !!!
This means that the user is prompted with a dialog every time the screen is repainted or layout is done. That's quite bad.

[Pat Watson]

Norm Radder wrote:The  paintComponent method is in the ShapesPanels class so the drawing coordinates are for that panel.  If you want the drawing to be defined by the coordinates for the centerDrawPanel object, then the code needs to override the paintComponent method for that instance of JPanel.

Yes I previously tried an inner class but nothing was happening with ActionListener on the button
Here is what I had

/************************************************************************/
	@SuppressWarnings("serial")
	public class DrawingPanel extends JPanel{
		
		// paintComponent
		@Override
		public void paintComponent(Graphics g) {
			super.paintComponent(g);

			setPreferredSize(new Dimension(600, 600));
			if(rectangle.isSelected()) {
				r = new ShapeRectangle(getDim1(), getDim2());
				g.setColor(Color.RED);
				g.fillRect(50, 50,r.getW(), r.getL()); 
			}else if (circle.isSelected()) {
				c = new ShapeCircle(getDim1(), getDim2());
				g.setColor(Color.RED);
				g.fillOval(100,100,c.getW(), c.getL());
			}else if(square.isSelected()) {
				s = new ShapeSquare(getDim1());
				g.setColor(Color.BLUE);
				g.fillRect(50, 50, s.getW(), s.getW());
			}
			
				 
		}// End paintComponent

	}// end DrawingPanel
	
	JPanel p1 = new DrawingPanel();
	
	
	/************************************************************************/

	// Listener handler
	protected class buttonHandler implements ActionListener{
		public void actionPerformed(ActionEvent ae) {
			p1.repaint();
		}
	}// end buttonHandler Class

[Norm Radder]

nothing was happening with ActionListener

Please explain what that means.  What actions did you take, what did the program do.
Add some print statements to show what methods are being executed. Print a unique message in all the relevant methods so the execution trail is shown,
Also print out the bounds for all the GUI class instances involved.

[Paul Clapham]

I think your problem is that you're creating a class which implements ActionListener, when all you need is an ActionListener. That's just extra stuff to distract and confuse. Just create (and use) an ActionListener:

ActionListener repainter = new ActionListener() {
        public void actionPerformed(ActionEvent ae) {
            p1.repaint();
        }
}

Or better still, a newer and less verbose way:

ActionListener repainter = ae -> p1.repaint();

[Paul Clapham]

And also... mixing AWT and Swing components can introduce unhelpful problems. Stick with Swing components: JLabel, JButton, JTextField, and any others that I missed in your earlier posts.

[salvin francis]

Although we have a rule against doing this (https://coderanch.com/wiki/659991/Code-Mill), I am making an exception here since you have shared your complete code. I have modified your program and removed all the unnecessary code:

import static java.util.stream.Collectors.toList;
//-- All imports here...

class ShapeDrawingApp {
	public static void main(String... salvin) {
		SwingUtilities.invokeLater(() -> new ShapeDrawingApp().initUI());
	}

	private JFrame frame;
	private ButtonGroup shapeSelectionGroup;
	private ShapeDrawingPanel drawShapePanel;

	public ShapeDrawingApp() {
		shapeSelectionGroup = new ButtonGroup();
		drawShapePanel = new ShapeDrawingPanel();
	}

	protected void initUI() {
		frame = new JFrame("My Drawing App");
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

		drawShapePanel.setPreferredSize(new Dimension(400, 400));
		drawShapePanel.setBorder(new EtchedBorder(EtchedBorder.LOWERED));

		frame.add(createChooseShapePanel(), BorderLayout.NORTH);
		frame.add(drawShapePanel, BorderLayout.CENTER);
		frame.add(createButtonsPanel(), BorderLayout.SOUTH);

		frame.pack();
		frame.setLocationRelativeTo(null);
		frame.setVisible(true);
	}

	protected JPanel createButtonsPanel() {
		JPanel buttons = new JPanel();
		JButton drawButton = new JButton("Draw Selected");
		JButton eraseButton = new JButton("Erase");

		buttons.add(drawButton);
		buttons.add(eraseButton);

		drawButton.addActionListener(e -> drawSelectedItem());
		eraseButton.addActionListener(e -> doErase());
		return buttons;
	}

	protected JPanel createChooseShapePanel() {
		JPanel chooseShape = new JPanel();
		chooseShape.setPreferredSize(new Dimension(400, 50));
		List<JRadioButton> shapeChoices = Arrays.asList("Circle", "Square", "Rectangle")
												.stream()
												.map(text -> {
													JRadioButton radio = new JRadioButton(text);
													radio.setActionCommand(text);
													return radio;
												})
												.collect(toList());
		for (JRadioButton item : shapeChoices) {
			shapeSelectionGroup.add(item);
			chooseShape.add(item);
		}
		shapeChoices.stream()
					.findFirst()
					.ifPresent(i -> i.setSelected(true));
		return chooseShape;
	}

	private void doErase() {
		drawShapePanel.clear();
	}

	private void drawSelectedItem() {
		drawShapePanel.setShape(shapeSelectionGroup	.getSelection()
													.getActionCommand());
	}
}

class ShapeDrawingPanel extends JPanel {
	private String shapeText;

	@Override
	protected void paintComponent(Graphics g) {
		super.paintComponent(g);
		Rectangle bounds = g.getClipBounds();
		//-- TODO: use strategy pattern
		if ("circle".equalsIgnoreCase(shapeText)) {
			g.setColor(Color.GREEN);
			g.fillArc(bounds.width / 3, bounds.height / 3, bounds.width / 5, bounds.width / 5, 0, 360);
		} else if ("rectangle".equalsIgnoreCase(shapeText)) {
			g.setColor(Color.BLUE);
			g.fillRect(bounds.width / 3, bounds.height / 3, bounds.width / 5, bounds.height / 4);
		} else if ("square".equalsIgnoreCase(shapeText)) {
			g.setColor(Color.RED);
			g.fillRect(bounds.width / 3, bounds.height / 3, bounds.width / 5, bounds.width / 5);
		} else {
			g.setColor(UIManager.getColor("Panel.background"));
			g.fillRect(bounds.x, bounds.y, bounds.width, bounds.height);
		}
	}

	public void clear() {
		setShape(null); //-- TODO: use null object instead
	}

	public void setShape(String shapeText) {
		this.shapeText = shapeText;
		repaint();
	}
}

Since your initial problem is based on listeners, notice how I have used actionCommand in the code above. You can also note that the total number of field variables are bare minimum. The shapes in my program are also responsive to resizing the frame. The code is a bit long since it's swing UI code. There are some TODOs in the code above that I suggest you can research on.
Hope this helps.

[Campbell Ritchie]

Norm Radder wrote:. . . missing Rectangle2D class definition. . . .

I can see another potential problem: there already is a class called Rectangle2D. If you use that awt.geom class, you can have all sorts of confusion.

. . These are my codes . . .

Sorry. Not pleased with that inheritance. I don't know about the Shape class, but let's forget that and create a Shape2D class without specifying a supertype, so its direct supertype is now Object. Let's start with the class looking the same as what you showed.

1: Don't give subtypes direct access to the fields: as usual all fields other than global constants should be private, and in this case probably final, too. Any subtype access would be via the getXXX() methods.

2: Don't override the getXXX() methods. In fact I would make the getXXX() methods final, too.

3: I don't think you need a direct instance of Shape2D: make that class abstract.

4: Minor point: I would call the fields and constructor parameters length and width. It isn't difficult to guess what l and w mean, but length and width are much easier to read.

5: At this point you will have nothing in the subtypes but a constructor. In my opinion, that is what inheritance should look like.

You may consider adding getArea() or getPerimeter() methods; if you do, make them abstract methods in Shape2D.
Consider whether your classes need toString(), hashCode(), and equals() methods.
Advanced suggestion: Find Effective Java by Joshua Bloch, page 5 in the 2nd and 3rd editions. Can you restrict the access of the constructors and use factory methods such that Rectangle2D.getInstance(5, 5) returns a Square instance?

[Campbell Ritchie]

Salvin, can we have a bit of explanation about the use of Streams and the factory for panels please? I think that may go over OP's head otherwise. I am still not happy about multiple ifs, which I mentioned in my first post in this thread. Is there some way to map the text on each button to a shape class? Should we use Actions instead of action listeners?
Please explain why you got rid of the variables c, r, and s from an earlier version of the code.
What would happen if you made Shape implement a Paintable interface?

package shapes;

/**
 * Always remember to give interfaces documentation comments
 */
interface Shape
{
   /**
    * Your documentation comments should explain how the interface works,
    * and how it should be implemented, and they usually occupy more space
    * than the methods, at least in a "classical" interface.
    */
   void paintYourself(Graphics g);
}

/* Version 2 */ package shapes; /** * Always remember to give interfaces documentation comments */ interface Shape {   /**    * Your documentation comments should explain how the interface works,    * and how it should be implemented, and they usually occupy more space    * than the methods, at least in a "classical" interface.    */   void paintYourself(Graphics g);   /**    * as above    *@return the area of this shape    */   double getArea();   /**    * No cheating: you must write documentation comments    *@return the perimeter/circumference of this shape    */   double getPerimeter(); }You can now write

@Override
protected void paintComponent(Graphics g)
{
   super.paintComponent(g);
   Graphics2D g2d = (Garphcs2D)g.create();
   shape s = ...
   s.paintYourself(g2d);
}

The create() method takes a copy of the Graphics object in case you do something like affine transforms with it because they can spoil the effect of repeated paint events. Rotate scale and translate aren't too bad, but shear can cause such problems. I shall leave correcting the spellling as “an exercise for the reader”.

[Campbell Ritchie]

Some of us have been writing xyz -> pqr() for so long that we have forgotten it is unfamiliar code to some people. Have a look in the Java™ Tutorials; pay particular attention to the section about lambda expressions.

[salvin francis]

Let me explain a few sections of my code for better understanding. The code starts with a lambda expression:

SwingUtilities.invokeLater(() -> new ShapeDrawingApp().initUI());

This can be written as:

SwingUtilities.invokeLater(new Runnable() {
	@Override
	public void run() {
		ShapeDrawingApp sda = new ShapeDrawingApp();
		sda.initUI();
	}
});

Effectively, the main program only creates an object of ShapeDrawingApp and then calls it's initUI() method. This follows the paradigm that https://coderanch.com/wiki/660020/Main-Pain
Now, you might wonder why dont we directly call the method instead of using invokeLater. The answer is well explained in the java tutorials here: https://docs.oracle.com/javase/tutorial/uiswing/concurrency/initial.html
It simply states:

java tutorial wrote:all code that creates or interacts with Swing components must run on the event dispatch thread

I suggest reading about lambdas a bit if you find that statement confusing: https://docs.oracle.com/javase/tutorial/java/javaOO/lambdaexpressions.html
To put it simply, it's just a compact way of writing anonymous classes with a single method.

Now, let's go to the variables... As you can see, I have only used 3 variables: The JFrame, the ButtonGroup and the ShapeDrawingPanel. This way, we only have field variables that are required to be accessed across methods.
The ButtonGroup has a method called getSelection. This method returns the selected button from the "circle", "square", "rectangle" ones. Hence we don't a reference to each of them (your original circle, square, triangle, rectangle, sphere, cube, cone, cylinder, torus variables). We are only interested in the selected one. Let me know if that makes sense

Moving to the initUI method, I created all panels in methods to keep the code neater and concise.
Looking at the code for JRadioButton, the code you wrote was repeating the same steps for each of them, so this is where a loop comes into picture.

List<JRadioButton> shapeChoices = Arrays.asList("Circle", "Square", "Rectangle")
                                                .stream()
                                                .map(text -> {
                                                    JRadioButton radio = new JRadioButton(text);
                                                    radio.setActionCommand(text);
                                                    return radio;
                                                })
                                                .collect(toList());

The code reads as:
1. Create a list of String having "Circle", "Square" and "Rectangle" in it. 2. Now, loop through this list with loop variable as "text". For every "text": 2.1 Create a radio button with the text 2.2 Set the radio button action command to this same text. This is so that we can use it later to check what shape is needed to be drawn 3. Collect all the radio buttons in a list. Notice that I have added a static import for the toList() method.We can discuss this further if it's a bit confusing. Streams may seem a bit scary at first ;)
Once we have a list of all created JRadio buttons, we simply loop through them and add them to the button group as well as the panel. As you probably discovered already, adding them to the group creates this bond that only allows one of them to be selected. I have also taken the first item from the list using stream's findFirst() method and set it to selected by default. This is in line with your original code.

Now that the GUI is done, we add the listeners to the buttons. Since shapeSelectionGroup is a field variable, we can access it and find out which one is selected every time the user clicks the button. Additionally, since drawShapePanel is a field variable as well, we can ask it to draw our selected shape. As Campbell rightly stated, the if-else condition is still not a good way to draw the shape especially given that we know that they can be different objects with behaviors.

I'll let you work that one out, let us know if you are still unable to get that to work. Hint, Campbell has shared a nice little interface that can draw itself !!

[salvin francis]

Campbell Ritchie wrote:Should we use Actions instead of action listeners?

Yes, that's a good idea. It exactly matches our purpose in this case.

[Frits Walraven]

Congratulations Pat Watson,

Your question has made it to our Journal    

Have a Cow!