CODEWITHSUNDEEP
javaswingjpanel
Billy M.
Billy M.

Reputation: 369

How do I dynamically change the reference to a JPanel inside a JFrame?

Yes, this probably looks like a duplicate question, but bear with me. Take the code below, that is functional:

private void setMainLayout(Container pane) {

    String imagePath = Start.getProperty("IMAGE_DIR");      

    characters.add(char1); // pseudocode
    characters.add(char2);
    characters.add(char3);
    characters.add(char4);

    // "CharacterDisplay.getMainLayout()" returns a Box object:
    for (CharacterDisplay character : characters)
        character.getMainLayout().setBorder(BorderFactory.createMatteBorder(2, 2, 2, 2, Color.WHITE));

    // "mainFrame" is a JFrame:
    mainFrame.setLayout(new GridBagLayout());
    GridBagConstraints gbc = new GridBagConstraints();

    /* do random gridbagconstraints stuff */   

    pane.add(characters.get(0).getMainLayout(), gbc);

    /* do random gridbagconstraints stuff */   

    // "nonCharacterArea" is a JPanel:    
    nonCharacterArea.setOpaque(true);
    nonCharacterArea.setBackground(Color.BLACK);
    nonCharacterArea.setLayout(new GridBagLayout());
    GridBagConstraints constCenter = new GridBagConstraints();

    /* do random gridbagconstraints stuff */  

    nonCharacterArea.add(actionPane, constCenter); // actionPane is a kind of JPanel

    /* do random gridbagconstraints stuff */        

    nonCharacterArea.add(menuPane, constCenter); // menuPane is a kind of JPanel
    pane.add(nonCharacterArea, gbc);

    /* do random gridbagconstraints stuff */      

    pane.add(characters.get(1).getMainLayout(), gbc);

    gbc.gridx = 0;
    gbc.gridy = 2;      

    pane.add(characters.get(2).getMainLayout(), gbc);

    gbc.gridx = 2;
    gbc.gridy = 2;        

    pane.add(characters.get(3).getMainLayout(), gbc);
} // setMainLayout

I want to be able to change the actionPane object dynamically during execution. What is the best way to accomplish this? I wrote this pseudo-code block specifically to show that it's not just as simple as the other examples people have posted in similar questions -- because it is based on a precise placement of the JPanel at a certain spot on the screen, and this setMainLayout() method should not have to be called each time I want to change only the actionPane object.

Sometimes it will be a side-scrolling screen, sometimes it will be a shop interface, it can be many different kinds of things.

Ideas? Thanks.

Upvotes: 0

Views: 134

Answers (2)

user949300
user949300

Reputation: 15729

If the actionPane is taken from a small set of Panels that are pretty much predefined, with relatively minor live updates and changes, a good option is to use a CardLayout, and switch between the predefined actionPanes as needed.

If the actionPane is very dynamic and you really cannot predict ahead of time what it might be, then @Greg Kopff has a reasonable answer.

Upvotes: 4

Greg Kopff
Greg Kopff

Reputation: 16545

Don't add and remove the actionPane - leave that in place, but add/remove a child component to actionPane. This task then becomes relatively trivial because actionPane contains only a single component.

Upvotes: 3

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