使用内部框架时，主面板的重新粉刷无法正常工作

Question

I'm having the following bug/problem and I havent been able to found solution yet on web or example of someone with similar issue.Basicaly I have a main frame that contains a panel of the same size(acting as the main panel) and When you press "Enter" an internal frame pop up(on top of where the playersprite is) acting as the inventory and then the control is passed to it and if you press "Enter" again the inventory is destroyed and control is passed back to the main panel.

the repaint function is called and the character and the map is then redrawn and this work about 90% of the time.The other 10% or less of time whenever the inventory is destroyed it seems the repaint is called(and work) except nothing is drawn its as if it draw on the destroyed panel because if I add a debug keypress that call repaint on the mainpanel(thescreen) everything is back to normal.

of course I could just repaint the character every loop in the run() method but thats terrible since I will only repaint if something changed(ie I moved)

I removed all the move and other code since they arent useful and still get the problem with the below code.You can think of the Character class as a plain drawn square.Anyone as any insight on why this is happening?

public class main extends JFrame implements Runnable{
    private boolean gameRunning=true;
    private Character Link;
    private MainScreen theScreen;
    public final int ScreenHeight=500;
    public final int ScreenWidth=500;
    public boolean inMenu=false;
    Block ablock=new Block(200,200);
    public class Inventory extends JInternalFrame{
        public Inventory(){
            setBounds(25,25,300,300);
            setDefaultCloseOperation(HIDE_ON_CLOSE);
            setVisible(true);
            addKeyListener(new KeyAdapter() {
                public void keyPressed(KeyEvent e){
                    int key=e.getKeyCode();
                    if(key==KeyEvent.VK_ENTER){
                    try{                                    
                        setClosed(true);
                        theScreen.requestFocusInWindow();
                        theScreen.repaint();
                        inMenu=false;
                    }                               
                    catch(Exception ex){}
                    }
            }});
        }
    }
    class MainScreen extends JPanel{
        MainScreen(){
            super();
            setIgnoreRepaint(true);
            setFocusable(true);
            setBounds(0,0,ScreenWidth,ScreenHeight);
            setVisible(true);
            setBackground(Color.white);
        }
        public void paintComponent(Graphics g){
            super.paintComponent(g);
            Link.draw(g);
            g.drawImage(ablock.getImg(),ablock.getX(), ablock.getY(),null);
        }
    }
    main(){
        super();
        final JDesktopPane desk = new JDesktopPane();
        theScreen=new MainScreen();
        add(theScreen);
        theScreen.addKeyListener(new KeyAdapter() {
            public  void keyPressed(KeyEvent e){
                int key=e.getKeyCode();
                if(key==KeyEvent.VK_ENTER){
                    inMenu=true;
                    Inventory myInventory=new Inventory();
                    desk.add(myInventory);
                    myInventory.requestFocusInWindow();
                }
            }   
    });
        add(desk);
        try {
            UIManager.setLookAndFeel(
                    UIManager.getSystemLookAndFeelClassName());

            }
        catch (Exception e) {}
        setTitle("Project X");
        setResizable(false);
        Link=new Character();
        setSize(500,500);
        setVisible(true);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
    }
    public static void main(String[] args) {
        main Game=new main();
        new Thread(Game).start();
    }
    public void run(){
            //omitted/irrelevant only contains  a FPS count
          }
    }

}

Answer 1

Don't use KeyListeners. Use Key Bindings .

Don't use a Thread. Use a Swing Timer for animation so updates will be done on the EDT.

Don't use an Internal Frame for a popup window. Use a JDialog.

Do custom painting on a JPanel, not a JDesktopPane.

Don't use setIgnoreRepaints(). That is used for active rendering.

Don't use empty catch clauses.

Use standard Java naming conventions. Classes start with upper cases characters, variable names do not.

Don't use setBounds(). Use a Layout Manager.