How to add multiple JComponents to a JPanel?

Question

I'm trying to add multiple components to a JPanel, but only the most recently added component is displaying.

It seems like the problem is that the layout can only handle 1 component at a time, but I'm at a loss as to how to actually fix it. I've tried adding the components to a separate panel and then adding that to the main panel, and I've tried a few different layouts to no avail.

Here's the relevant code, I'm currently trying just to get two TextRects, which extends JComponent, on the panel:

public class ProjectView extends JFrame implements IProjectView, Observer {

private IProjectModel model;
private ProjectController controller;
private JPanel panel;

public ProjectView(IProjectModel model){
    this.model = model;
    ((Observable) this.model).addObserver(this);

    controller = new ProjectController(this.model, this);

    addWindowListener(controller);
    getContentPane().setLayout(new BorderLayout());

    populateMenuBar();

    panel = new JPanel(new BorderLayout());

    getContentPane().add(panel);
    pack();
    setMinimumSize(getSize());

    setExtendedState(JFrame.MAXIMIZED_BOTH);
}

public void generateUML(ArrayList<ArrayList<String>> content){
    panel.add(new TextRect(content.get(0), 10, 10));
    panel.add(new TextRect(content.get(0), 100, 100));

    panel.revalidate();
}

Any help would be appreciated.

Edit:

generateUML is called from an ActionListener in the controller when the user presses a "Generate UML" button:

 private void generateUML(){
    ArrayList<IClassModel> classes = new ArrayList<IClassModel>();
    classes = model.getClasses();
    ArrayList<ArrayList<String>> allClasses = new ArrayList<ArrayList<String>>         ();
    for(int i = 0 ; i < classes.size() ; i++){
        classContent = new ArrayList<String>();
        classContent.add(classes.get(i).getClassName());
        classContent.addAll(classes.get(i).getMethodNames());
        classContent.addAll(classes.get(i).getObjectClasses());
        allClasses.add(classContent);
    }

    System.out.println("1: " + allClasses.get(0));
    System.out.println("2: " + allClasses.get(1));
    view.generateUML(allClasses);
}

Answer 1

Try this

panel.add(new TextRect(content.get(0), 10, 10), BorderLayout.SOUTH);
panel.add(new TextRect(content.get(0), 100, 100), BorderLayout.CENTER);

panel.revalidate();
panel.repaint()

If you set the BorderLayout, you should use its properties. Also, after calling revalidate(), you should call repaint();

Another option is a GridLayout

panel = new JPanel(new GridLayout(1, 2)); // or 2, 1 depending if you want them 
                                          // laid out vertically or horizontally

panel.add(new TextRect(content.get(0), 10, 10));
panel.add(new TextRect(content.get(0), 100, 100));

Answer 2

You are using BorderLayout for you panel. The add method will add to the the center of the panel, and will expand tofthe size that is not being used up by north, south, east, and west. Perhaps you are looking for FlowLayout that just places the components next to each other. Only one component can appear in the any of the parts of a BorderLayout. So if you add two components to the center only the last will be visible.