How can I switch between jpanels?

Question

I\'m still very new to java programming, so please help me to correct any mistakes I might have overlooked or give tips on how to improve this program.

Okay, so a lo

Answer 1

The best way to approach this is using a CardLayout.

Notes

• A button with an ActionListener is far better than a MouseListener over a rectangle.
  • The button will show focus when the mouse is pointed at it, or the component is tabbed to via the keyboard.
  • The button is keyboard accessible.
  • The button has facility to support multiple icons built in (e.g. for 'initial look', focused, pressed etc.)
• White space in the GUI is provided around the menu panel and game by adding an EmptyBorder
• The button is made larger by setting a margin.
• Adjust margins, borders and preferred size according to need. These sizes were set by me so as not to make the screenshots too large.
• See more tips in the code comments.

Code

Here is the MCTaRE (Minimal Complete Tested and Readable Example) that produced the above screenshots.

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
import javax.swing.border.EmptyBorder;

public class PipesGame {

    public static void main(String[] args) {
        Runnable r = new Runnable() {
            @Override
            public void run() {
                // the GUI as seen by the user (without frame)
                final CardLayout cl = new CardLayout();
                final JPanel gui = new JPanel(cl);
                // remove if no border is needed
                gui.setBorder(new EmptyBorder(10,10,10,10));

                JPanel menu = new JPanel(new GridBagLayout());
                JButton playGame = new JButton("Play!");
                ActionListener playGameListener = new ActionListener() {

                    @Override
                    public void actionPerformed(ActionEvent e) {
                        cl.show(gui, "game");
                    }
                };
                playGame.addActionListener(playGameListener);
                Insets margin = new Insets(20, 50, 20, 50);
                playGame.setMargin(margin);
                menu.add(playGame);
                gui.add(menu);
                cl.addLayoutComponent(menu, "menu");

                JPanel pipes = new Pipes();
                gui.add(pipes);
                cl.addLayoutComponent(pipes, "game");

                JFrame f = new JFrame("Pipes Game");
                f.add(gui);
                // Ensures JVM closes after frame(s) closed and
                // all non-daemon threads are finished
                f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
                // See https://stackoverflow.com/a/7143398/418556 for demo.
                f.setLocationByPlatform(true);

                // ensures the frame is the minimum size it needs to be
                // in order display the components within it
                f.pack();
                // should be done last, to avoid flickering, moving,
                // resizing artifacts.
                f.setVisible(true);
            }
        };
        // Swing GUIs should be created and updated on the EDT
        // http://docs.oracle.com/javase/tutorial/uiswing/concurrency
        SwingUtilities.invokeLater(r);
    }
}

class Pipes extends JPanel {

    Pipes() {
        setBackground(Color.BLACK);
        setForeground(Color.WHITE);
    }

    @Override
    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        g.drawString("Pipes game appears here..", 170, 80);
    }

    @Override 
    public Dimension getPreferredSize() {
        // adjust to need
        return new Dimension(500,150);
    }
}

Answer 2

This works with a mouse click on the menu. You can change it later, to a click on some button or whatever you want.

I added a MouseListener to the Game class. When the user presses the mouse on the menu JPanel, it adds the Pipes JPanel to JFrame and calls the pack method.

Game.java:

import java.awt.Point;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.geom.Rectangle2D;

import javax.swing.JFrame;
import javax.swing.SwingUtilities;
import javax.swing.Timer;

public class Game {

    GameMenu menu = new GameMenu();
    Pipes game;
    boolean start = false;
    JFrame f;
    Rectangle2D menuRect = new Rectangle2D.Double(20, 20, 60, 40);

    public Game() {
        f = new JFrame();

        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.add(menu);
        f.setTitle("Pipe Game");
        f.setResizable(false);
        f.pack();
        f.setLocationRelativeTo(null);
        f.setVisible(true);



        menu.addMouseListener(new MouseAdapter() {

            @Override
            public void mousePressed(MouseEvent e) {

                Point click = new Point(e.getX(), e.getY());
                System.out.println("Clicked on the Panel");

                if(menuRect.contains(click))
                {
                    System.out.println("Clicked inside the Rectangle.");

                    start = true; 
                    menu.setVisible(false);
                    game = new Pipes();
                    f.add(game);
                    f.pack();

                    Timer timer = new Timer(10, new ActionListener() {  //pipe speed
                        @Override
                        public void actionPerformed(ActionEvent e) {
                            game.move();
                        }
                    });
                    timer.start();

                    Timer refresh = new Timer(30, new ActionListener() {    //refresh rate
                        @Override
                        public void actionPerformed(ActionEvent e) {
                            game.repaint();
                        }
                    });
                    refresh.start();   
                }
            }

            @Override
            public void mouseReleased(MouseEvent e) {
            }
        });

    }

    public static void main(String args[]) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                new Game();
            }
        });
    }
}

Answer 3

"Is there a way for me to add my GameMenu jpanel to my jframe, and then replace it with the Pipes jpanel?"

As other have suggested, for this you want a CardLayout. It is very simple to you. Personally, I always wrap my CardLayout in a JPanel rather than the JFrame, just force of habit.

What you want to do is have a mainPanel that will have the CardLayout

CardLayout card = new CardLayout();
JPanel mainPanel = new JPanel();

Then you want to add your panels to the mainPanel. What the CardLyaout does is layer the panels, making just one visible at a time. The first one you add, will the in the foreground. Also when you add the panel, you'll also want to issue it a key it can be called from. The key, can be any String you like.

mainPanel.add(gameMenu, "menu");
mainPnael.add(pipes, "pipe");

Now gameMenu is the only panel shown. To show pipes, all you do is use this method

• public void show(Container parent, String name) - Flips to the parent that was added to this layout with the specified name, using addLayoutComponent. If no such component exists, then nothing happens.

So you'd use, card.show(mainPanel, "pipes");

Whatever even you want to trigger the showing of pipes, just add that line in that event handler. You could add a button or something to the GameMenu that will allow movement to the Pipes panel.