Issue with adding a JPanel onto another JPanel

Question

I am making a game and I have it so when I press a button on a menu I made, it loads the game. Both the game and the menu are JPanels. The problem is when I click the button it loads the JPanel but the keyboard input doesn't work. Why might this be happening? Here is the my code:

public class Menu extends JPanel  {
    static boolean load = false;
    JButton play = new JButton("play");
    GamePanel panel = new GamePanel();

    public Menu(){
        setLayout(new FlowLayout());
        add(play);


        setVisible(true);  
        play.addActionListener(new ActionListener() {

            public void actionPerformed(ActionEvent e) {
                    Runner.panel.setPreferredSize(new Dimension(570,700));
                    add(Runner.panel,0,0);
                    //repaint();
                    validate();
            }
       });
   }

   public void paint(Graphics g){
       super.paint(g);
       Graphics2D g2d = (Graphics2D) g;
       draw(g2d);

   }

   public void draw(Graphics2D g2d){

       g2d.drawImage(getBulletImage(),0,0,null);

   }



   // gets the image file for the player class
   public Image getBulletImage(){
       ImageIcon ic = new ImageIcon("Menu.png");
       return ic.getImage();
   }

}

When the button is clicked in, it adds a JPanel on top of the current JPanel.

For better help sooner, post an [MCVE](http://stackoverflow.com/help/mcve) (Minimal Complete and Verifiable Example). — Andrew Thompson, Jun 11 '14 at 01:12

score 1 · Answer 1 · edited May 23 '17 at 12:20

Read this post JPanel not responding to keylistener that is asked in the same context.

Some Points:

Override paintComponent() method of JPanel instead of overriding paint() method.

Sample code:

@Override
public void paintComponent(Graphics g){
    super.paintComponent(g);
    // your custom painting
}

Override getPreferredSize() method instead of setPreferredSize() method. Don't set the size of the component and just hand over it to Layout Manager to set the size and position of the components that why it's made for.

Sample code:
```
@Override
public Dimension getPreferredSize(){
    return new Dimension(100,50);
}
```
Read more Should I avoid the use of set(Preferred|Maximum|Minimum)Size methods in Java Swing?
Use SwingUtilities.invokeLater() to make sure that EDT is initialized properly.

Read more
- Why to use SwingUtilities.invokeLater in main method?
- SwingUtilities.invokeLater

score 0 · Answer 2 · answered Jun 10 '14 at 15:32

0

Try adding play.setFocusable(true); and play.requestFocus(); after you have created the new JPanel. This should put the focus in the new panel and allow keyboard input

answered Jun 10 '14 at 15:32

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2

+1 for making the panel focusable. -1 for suggesting requestFocus(). Don't use requestFocus(). The proper method to use is `requestFocusInWindow()` – camickr Jun 10 '14 at 15:56

Issue with adding a JPanel onto another JPanel

2 Answers2

Some Points: