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javaswinglayout-managerboxlayout

BoxLayout Displaying Incorrectly

I'm trying to create a pretty simple application that has a JSplitPane (which is divided into a JTabbedPane and a JPanel) above a status bar panel. I want to use a simple layout (i.e. BoxLayout, FlowLayout, or BorderLayout), but I've tried and they all give me the same error. I've simplified the code as much as possible to show the error.

The error is that there should only be 2 regions in the main box layout (the frame): a top (with the JSplitPane, which has the black border) and a bottom (with the JPanel status bar). However, when I add the status bar, a third region is created in the upper left that contains nothing. Any ideas on how to get rid of it?

public static void main(String[] args) {
    JFrame frame = new JFrame("Application");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.getContentPane().setLayout(new BoxLayout(frame.getContentPane(), BoxLayout.Y_AXIS));

    // Create left side of the application
    JTabbedPane tabby = new JTabbedPane(JTabbedPane.LEFT);

    // Create right side of the application
    JPanel rightPanel = new JPanel(new BorderLayout());

    // Create the status bar at the bottom
    JPanel statusBar = new JPanel(new BorderLayout());
    JPanel statusBarPanel = new JPanel();
    statusBarLabel = new JLabel("Status Bar");
    statusBarPanel.add(statusBarLabel);
    parent.add(statusBarPanel);

    JSplitPane mainPain = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, tabby, rightPanel);
    frame.add(mainPain);
    frame.add(statusBar);
    frame.pack();
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);

Application with 3 segments.

Solution

  • I'm trying to create a pretty simple application that has a JSplitPane (which is divided into a JTabbedPane and a JPanel) above a status bar panel.

    Normally you would just use the default BorderLayout of the frame and then do:

    frame.add(splitPane, BorderLayout.CENTER);
frame.add(statusBar, BorderLayout.PAGE_END);

    A status bar is typically one or more labels that display information so they are display in a fixed size at the bottom.

    The other panel will then contain the main components of the application. These components will then get any extra space available to the frame as it is resized.

    but I've tried and they all give me the same error

    parent.add(statusBarPanel);

    The variable "parent" doesn't exist. Get rid of it. Add the status bar to the frame as shown above.