My code is not working. How should I add a JScrollPane on a JTextArea that is in a JTabbedPane?-CodePudding

this is the code I have so far

public class WindowHelpGui extends JFrame{
    JScrollPane scroll;
    //constructor
    public WindowHelpGui(){
         //add window title
        super("Help");
        //set window layout
        setLayout(null);

        JTabbedPane tabbedPane = new JTabbedPane();
        tabbedPane.setBounds(10, 10, 750, 550);

        JPanel panel1 = new JPanel();
        JPanel panel2 = new JPanel();
        JPanel panel3 = new JPanel();

        panel1.add(new JTextArea("\nDRAFT TEXT 101 
\ncodnvfdinofndovndofinvinfdivnifdnvidfnviofnivnidfnviofdnvindfinv
ivondfviondfiovndfionvifdnvionivfdninfdinfivnidfovniofnviofnvifdnv
fndiovnf\nh\ne\nl\nl\no\n\nf\nr\no\nm\n\nt\nh\ne\n\no\nt\nh" 
       "e\nr\n\ns\ni\nd\ne\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
nHello")); 
       panel2.add(new JTextArea("panel2 working"));
       panel3.add(new JTextArea("panel3 working"));
       JScrollPane scroll = new JScrollPane(panel1, JScrollPane.
HORIZONTAL_SCROLLBAR_NEVER, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDE
       add(scroll, panel1);

       tabbedPane.add("How to play", panel1);
       tabbedPane.add("Seeds", panel2);
       tabbedPane.add("Tools", panel3);
    
       //scroll = new Jscro
       this.add(tabbedPane);

        //set size of window
        setSize(800,600);
        //set visibility
        setVisible(true);
        //set resizable 
        setResizable(false);
        //set default close
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

when I run this I dont see any window popping up. Can someone help me please?

I have tried also tried using add(scroll, tabbedPane) but it just adds a new tab on my window.

CodePudding user response：

Call pack() before making your JFrame visible and use setPreferredSize() of the Jframe instead of setSize().

Add a setMinimumSize() as well to the JFrame.

Also there can only be one root component of a JFrame. Use a JPanel with a layout to add more components.

Don't use a null layout. It will require you to explicitly set position and size of each child component by using setBounds() method of each child.

Example code:

JFrame frame = new JFrame("Simple GUI");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
       
JLabel textLabel = new JLabel("I'm a label in the window",SwingConstants.CENTER);
textLabel.setPreferredSize(new Dimension(300, 100));      
frame.getContentPane().add(textLabel, BorderLayout.CENTER);       
//Display the window.       
frame.setLocationRelativeTo(null);       
frame.pack();       
frame.setVisible(true);

Read more about JFrame and how it works from here.

CodePudding user response：

The JTextArea must be added directly to the JScrollPane and you can add the scrollpane directly to the tabbedPane:

    JTextArea textArea = new JTextArea("\nDRAFT TEXT 101\ncodnvfdinofndovndofinvinfdivnifdnvidfnviofnivnidfnviofdnvindfinvivondfviondfiovndfionvifdnvionivfdninfdinfivnidfovniofnviofnvifdnvfndiovnf\nh\ne\nl\nl\no\n\nf\nr\no\nm\n\nt\nh\ne\n\no\nt\nh"  
            "e\nr\n\ns\ni\nd\ne\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\nn\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\nnHello");
    JScrollPane scrollPane = new JScrollPane(textArea, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);

    tabbedPane.add("How to play", scrollPane);

CodePudding user response：

You set the JTextArea into the ScrollPane constructor. Here is a runnable example (read comments in code):

import java.awt.Dimension;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTabbedPane;
import javax.swing.JTextArea;


public class WindowHelpGui extends JFrame {

    private static final long serialVersionUID = 34534L;
    
    private JTextArea textArea_1;
    private JTextArea textArea_2;
    private JTextArea textArea_3;
    
    private JTabbedPane tabbedPane;
    

    //constructor
    public WindowHelpGui() {
        createForm();
    }

    private void createForm() {
        //set window layout
//        setLayout(null);  // If possible, don't ever use a Null layout.

        //set resizable 
//        setResizable(false);  // It's nice to be able to resize from time to time.

        // add window title
        setTitle("Help");
        
        // set size of window
        setPreferredSize(new Dimension(800, 600));

        //set default close
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        // OPTIONAL - Set form on top of everything.
        setAlwaysOnTop(true);

        tabbedPane = new JTabbedPane();

        JPanel panel1 = new JPanel();
        JPanel panel2 = new JPanel();
        JPanel panel3 = new JPanel();

        textArea_1 = new JTextArea();
        textArea_1.setText("\nDRAFT TEXT 101\ncodnvfdinofndovndofinvinfdivnifdnvidfnviofnivnid"
                  "fnviofdnvindfinvivondfviondfiovndfionvifdnvionivfdninfdinfivnidfovniofnvio"
                  "fnvifdnvfndiovnf\nh\ne\nl\nl\no\n\nf\nr\no\nm\n\nt\nh\ne\n\no\nt\nhe\nr\n\n"
                  "s\ni\nd\ne\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n"
                  "\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\nHello");
        textArea_1.setCaretPosition(0);  // Set the caret to beginning of document.
        
        textArea_2 = new JTextArea();
        textArea_2.setText("Seeds Area Working");
        
        textArea_3 = new JTextArea();
        textArea_3.setText("Tools Area Working");

        JScrollPane scroll_1 = new JScrollPane();
        scroll_1.setViewportView(textArea_1);
        JScrollPane scroll_2 = new JScrollPane();
        scroll_2.setViewportView(textArea_2);
        JScrollPane scroll_3 = new JScrollPane();
        scroll_3.setViewportView(textArea_3);
        
        tabbedPane.add("How to play", scroll_1);
        tabbedPane.add("Seeds", scroll_2);
        tabbedPane.add("Tools", scroll_3);

        add(tabbedPane);
        
        pack(); // Now you can resize or maximize the form and everything will resize with it.
        
        setVisible(true);
        // Set Screen Location (after the pack())
        setLocationRelativeTo(null);
    }

    public static void main(String[] args) {
        new WindowHelpGui();
    }
    
}