JPanel not displaying components

Question

i am working on a simple html renderer- at the moment all i am trying to do is to add JTextPane components to two different JPanels (search and content). I can add the text panes to the search bar, however none of the components are displayed in the content panel. I get no compile time errors, im really at a loss as to what the problem could be.
this is the code im using-
public class Demo extends JFrame
    private JPanel search, content;
    private JSplitPane splitPane;
    //private ArrayList<JTextPane> textCollection;
    //private ArrayList<JTextPane> preCollection;
    //specifies the universal font size the content JPanel
    private final int fontSize = 18;
    //specifies the universal font size for the search JPanel
    private final int searchFontSize = 9;
    /** Creates a new instance of Main */
    public Demo()
      this.setTitle("DEMO!");
      this.setDefaultCloseOperation(EXIT_ON_CLOSE);
      //sets default size
      this.setSize(500, 500);
      //init panel controls- these will hold all rendered controls
      search = new JPanel();
      //use BoxLayout to ensure controls are positioned correctly
      search.setLayout(new BoxLayout(search, BoxLayout.Y_AXIS));
      search.setBackground(Color.white);
      content = new JPanel();
      content.setLayout(new BoxLayout(content, BoxLayout.Y_AXIS));
      content.setBackground(Color.white);
      //init JScrollPanes for both containers- allows for scrolling content of unlimited width/length
      JScrollPane contentScroller = new JScrollPane(content);
      JScrollPane searchScroller = new JScrollPane(search);
      //create a split pane container to contain both scroll panes
      splitPane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, searchScroller, contentScroller);
      //search bar recieves 25% of screen size
      splitPane.setDividerLocation(this.getWidth() / 4);
      this.getContentPane().add(splitPane);
      //show controls
      this.setVisible(true);
    * Creates a new text component- text contained will be line wrapped as the user resizes the JFrame
    public void newText(String text)
      //init properites of new JTextPane
      JTextPane tp = newTextPane(text);
      tp.setBackground(Color.blue);
      //line wrap add to content panel
      tp.setFont(new Font("Times New Roman", Font.PLAIN, fontSize));
      tp = getLines(tp, this.getWidth() - splitPane.getDividerLocation());
      content.add(tp);
      //resize text for search panel, line wrap and add to search panel
      tp.setFont(new Font("Times New Roman", Font.PLAIN, searchFontSize));
      tp = getLines(tp, splitPane.getDividerLocation());
      search.add(tp);
    * Creates a new preformated text component- this will not be line wrapped
    public void newPre(String preformattedContent)
        JTextPane tp = newTextPane(preformattedContent);
        tp.setBackground(Color.red);
        //add to content panel
        tp.setFont(new Font("Courier New", Font.PLAIN, fontSize));
        content.add(tp);
        //resize text for search panel and add to search panel
        tp.setFont(new Font("Courier New", Font.PLAIN, searchFontSize));
        search.add(tp);
    * Small method that init's a JTextPane component with common properites used by the newText/Pre methods
    private JTextPane newTextPane(String s)
      JTextPane tp = new JTextPane();
      //set text
      tp.setText(s);
      //may not be editied
      tp.setEditable(false);
      //align correctly
      tp.setAlignmentY(Component.TOP_ALIGNMENT);
      tp.setAlignmentX(Component.LEFT_ALIGNMENT);
      //set maximum size to preferred size, this makes sure the JTextComponent will not "stretch" when the JFrame is resized drastically
      tp.setMaximumSize(tp.getPreferredSize());
      return tp;
    * Sets the appropriate preferred height & width of a given JTextPanel, essentially word wrapping any text contained within
    private JTextPane getLines(JTextPane tp, int paneSize)
      //get preferred size of the text panel - this is the smallest size the text panel may be and still visibly display its text content
      Dimension d = tp.getPreferredSize();
      double prefWidth = d.getWidth();
      double prefHeight = d.getHeight();
      //factor will determine if line wrapping is required
      double factor = prefWidth / (double) paneSize;
      //if factor is greater than 1, the preferred width is greater than the size available in the pane
      if (factor >= 1){
        //set width so that it matches the size available on the screen
        d.setSize((double) this.getWidth() - paneSize, factor * prefHeight);
        tp.setMaximumSize(d);
        tp.setPreferredSize(d);
      //else- do nothing! resizing is not required
      return tp;
     * @param args the command line arguments
    public static void main(String[] args)
      Demo d = new Demo();
      d.newText("this is some content ooh look content i hope this is long enough to test the wrapp esfsdfsdf sdf sdfsdfsd fsdf sdfsdfsdfd sfsdf sdfsdxf sdf sdf sdfsd fsd fsdf ing");
      d.newPre("a     pre          formatted           lump of    =  text! !  !");
    public void paint(Graphics g)
        super.paint(g);
        System.out.println("update called");
        //preferred.setSize(this.getWidth() - (this.getWidth() / 4), this.getHeight());
        //max.setSize(this.getWidth(), this.getHeight());
}

Answer 1

Do you need to keep adding JTextPane's to the content and search panes or do you just need to append text to the existing panes?
If the later, you may want to create the JTextPanes in the constructor and use a set method to append/edit/remove text. As follows:
import javax.swing.*;
import java.awt.*;
public class Demo extends JFrame
    private JPanel search, content;
    private JSplitPane splitPane;
    private JTextPane contentTextPane;
    private  JTextPane searchTextPane;
    //private ArrayList<JTextPane> textCollection;
    //private ArrayList<JTextPane> preCollection;
    //specifies the universal font size the content JPanel
    private final int fontSize = 18;
    //specifies the universal font size for the search JPanel
    private final int searchFontSize = 9;
    /** Creates a new instance of Main */
    public Demo()
      this.setTitle("DEMO!");
      this.setDefaultCloseOperation(EXIT_ON_CLOSE);
      //sets default size
      this.setSize(500, 500);
      //init panel controls- these will hold all rendered controls
      search = new JPanel();
      //use BoxLayout to ensure controls are positioned correctly
      search.setLayout(new BoxLayout(search, BoxLayout.Y_AXIS));
      search.setBackground(Color.white);
      content = new JPanel();
      content.setLayout(new BoxLayout(content, BoxLayout.Y_AXIS));
      content.setBackground(Color.white);
      //init JScrollPanes for both containers- allows for scrolling content of unlimited width/length
      JScrollPane contentScroller = new JScrollPane(content);
      JScrollPane searchScroller = new JScrollPane(search);
      //create a split pane container to contain both scroll panes
      splitPane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, searchScroller, contentScroller);
      //search bar recieves 25% of screen size
      splitPane.setDividerLocation(this.getWidth() / 4);
      /*add the textpanes to the JPanels*/
      contentTextPane = new JTextPane();
      content.add(contentTextPane);
      searchTextPane = new JTextPane();
      search.add(searchTextPane);
      this.getContentPane().add(splitPane);
      //show controls
      this.setVisible(true);
    * Creates a new text component- text contained will be line wrapped as the user resizes the JFrame
    public void newText(String text)
      //init properites of new JTextPane
      JTextPane tp = newTextPane(text);
      tp.setBackground(Color.blue);
      //line wrap add to content panel
      tp.setFont(new Font("Times New Roman", Font.PLAIN, fontSize));
      tp = getLines(tp, this.getWidth() - splitPane.getDividerLocation());
      content.add(tp);
      //resize text for search panel, line wrap and add to search panel
      tp.setFont(new Font("Times New Roman", Font.PLAIN, searchFontSize));
      tp = getLines(tp, splitPane.getDividerLocation());
      search.add(tp);
    public void addToContent(String text){
         contentTextPane.setText(text);
    * Creates a new preformated text component- this will not be line wrapped
    public void newPre(String preformattedContent)
        JTextPane tp = newTextPane(preformattedContent);
        tp.setBackground(Color.red);
        //add to content panel
        tp.setFont(new Font("Courier New", Font.PLAIN, fontSize));
        content.add(tp);
        //resize text for search panel and add to search panel
        tp.setFont(new Font("Courier New", Font.PLAIN, searchFontSize));
        search.add(tp);
    * Small method that init's a JTextPane component with common properites used by the newText/Pre methods
    private JTextPane newTextPane(String s)
      JTextPane tp = new JTextPane();
      //set text
      tp.setText(s);
      //may not be editied
      tp.setEditable(false);
      //align correctly
      tp.setAlignmentY(Component.TOP_ALIGNMENT);
      tp.setAlignmentX(Component.LEFT_ALIGNMENT);
      //set maximum size to preferred size, this makes sure the JTextComponent will not "stretch" when the JFrame is resized drastically
      tp.setMaximumSize(tp.getPreferredSize());
      return tp;
    * Sets the appropriate preferred height & width of a given JTextPanel, essentially word wrapping any text contained within
    private JTextPane getLines(JTextPane tp, int paneSize)
      //get preferred size of the text panel - this is the smallest size the text panel may be and still visibly display its text content
      Dimension d = tp.getPreferredSize();
      double prefWidth = d.getWidth();
      double prefHeight = d.getHeight();
      //factor will determine if line wrapping is required
      double factor = prefWidth / (double) paneSize;
      //if factor is greater than 1, the preferred width is greater than the size available in the pane
      if (factor >= 1){
        //set width so that it matches the size available on the screen
        d.setSize((double) this.getWidth() - paneSize, factor * prefHeight);
        tp.setMaximumSize(d);
        tp.setPreferredSize(d);
      //else- do nothing! resizing is not required
      return tp;
     * @param args the command line arguments
    public static void main(String[] args)
      Demo d = new Demo();
      d.newText("this is some content ooh look content i hope this is long enough to test the wrapp esfsdfsdf sdf sdfsdfsd fsdf sdfsdfsdfd sfsdf sdfsdxf sdf sdf sdfsd fsd fsdf ing");
      d.newPre("a     pre          formatted           lump of    =  text! !  !");
      d.addToContent("testing the content panel");
    public void paint(Graphics g)
        super.paint(g);
        System.out.println("update called");
        //preferred.setSize(this.getWidth() - (this.getWidth() / 4), this.getHeight());
        //max.setSize(this.getWidth(), this.getHeight());
}If this is not the case let me know and Ill take another look. ;-)