CODEWITHSUNDEEP
javaswingjtextareaswingworker
Attilio
Attilio

Reputation: 65

Add a scrollbar to JFrame

I'm having some problem finding a way to add a scrollbar in a JFrame. I found a method to redirect System.{in,out,err} to a JTextArea but I was not successful in adding a scrollbar. I hope this question is not redundant.

public class console extends JTextArea {    

 public static JTextArea console(final InputStream out, final PrintWriter in) {
    final JTextArea area = new JTextArea();
        new SwingWorker<Void, String>() {
        @Override protected Void doInBackground() throws Exception {
            Scanner s = new Scanner(out);
            while (s.hasNextLine()) publish(s.nextLine() + "\n");
            return null;
        }
        @Override protected void process(List<String> chunks) {
            for (String line : chunks) area.append(line);
        }
    }.execute();
    area.addKeyListener(new KeyAdapter() {
        private StringBuffer line = new StringBuffer();
        public void keyTyped(KeyEvent e) {
            char c = e.getKeyChar();
            if (c == KeyEvent.VK_ENTER) {
                in.println(line);
                line.setLength(0); 
            } else if (c == KeyEvent.VK_BACK_SPACE) { 
                line.setLength(line.length() - 1); 
            } else if (!Character.isISOControl(c)) {
                line.append(e.getKeyChar());
            }
        }
    });

    return area;
}
public static void main(String[] args) throws IOException {
    PipedInputStream inPipe = new PipedInputStream();
    PipedInputStream outPipe = new PipedInputStream();
    System.setIn(inPipe);
    System.setOut(new PrintStream(new PipedOutputStream(outPipe), true));

    PrintWriter inWriter = new PrintWriter(new PipedOutputStream(inPipe), true);

    JFrame frame = new JFrame("\"Console\"");

    frame.getContentPane().add(console(outPipe, inWriter));
    frame.setSize(500, 500);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);

   // my code
  }

Upvotes: 4

Views: 2758

Answers (2)

Yassin Hajaj
Yassin Hajaj

Reputation: 21975

Create a new JScrollPane object and set the ScrollBarPolicies.

If you do not want to the scollbars to appear always, just delete the policies.

EDIT

Also, don't use KeyListener on text components, use a combination of DocumentListener and key bindings instead. (Thanks to @MadProgrammer)

Solution

JScrollPane jsp = new JScrollPane(console(outPipe, inWriter));
jsp.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
jsp.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
frame.getContentPane().add(jsp);

Output

enter image description here

Upvotes: 5

Rakesh KR
Rakesh KR

Reputation: 6527

You can try with,

public class Test {

    public static void main(String [] a) {

        final JFrame frame = new JFrame();
        frame.setSize(500, 500);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        JScrollPane pane = new JScrollPane(
                           JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
                           JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);

        frame.setContentPane(pane);

        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                frame.setVisible(true);
            }
        });
   }

}

Upvotes: 1

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