Change contentpane of Frame after button clicked

Question

I want to be able to set a JFrame's contentpane after a button inside one of that frame's JPanels has been clicked.

My architecture consists of a controller which creates the JFrame and the first JPanel inside of it. From within the first JPanel I'm calling a method: setcontentpane(JPanel jpanel) on the controller. However, instead of loading the passed JPanel it does nothing but removing all Panels (see code below)

ActionListener inside of the first JPanel:

public void actionPerformed(ActionEvent arg0) {
            controller.setpanel(new CustomPanel(string1, string2));
        }

Controller:

JFrame frame;

public void setpanel(JPanel panel)
{
    frame.getContentPane().removeAll();
    frame.getContentPane().add(panel);
    frame.repaint();
}

public Controller(JFrame frame)
{
    this.frame=frame;
}

Can anyone tell me what I'm doing wrong? Thanks :)

Answer 1

Call revalidate, then repaint. This tells the layout managers to do their layouts of their components:

JPanel contentPane = (JPanel) frame.getContentPane();

contentPane.removeAll();
contentPane.add(panel);
contentPane.revalidate(); 
contentPane.repaint();

Better though if you just want to swap JPanels is to use a CardLayout and have it do the dirty work.

Answer 2

I found a way to do what I outlined above.

Implementing the setpanel method like this:

public void setpanel(JPanel panel)
{
    frame.setContentPane(panel);
    frame.validate();
}

did the trick in my case.

I'm sure that I still need to fix something within my code, since pack() still shrinks the window, but at least the method posted above works.

Answer 3

Whenever you change a frame's containment hierarchy, you have to call pack().

From the docs:

Causes this Window to be sized to fit the preferred size and layouts of its subcomponents. [...] The Window will be validated after the preferredSize is calculated.