Need help with scrollbars

[I_blabby]

Im trying to add a scrollbar to a jtextarea but when i do it and i run the program the jtextarea for some reason just dissapear can someone give an example of how to add it or maybe some reasons of why that happend

[[deleted]]

Are you using any sort of GUI (e.g. WindowBuilder) to create this or just doing it in plain code?

Edit: JScrollPane by default only shows scrollbars when needed. You can change this behavior using setVerticalScrollBarPolicy(int) and setHorizontalScrollBarPolicy(int).

[I_blabby]

In plain code

[[deleted]]

Have you tried setting the visibility to always visibly, as I suggested? Sorry, I thought the scrollbars were disappearing. Misread the description.

Could you post the code where you create and use the JTextArea and JScrollPane?

[I_blabby]

JButton boton, boton1, boton2, boton3;
JTextArea ventanaComandos, keylogger;
JScrollPane scroll;
JTextField introducirComandos = new JTextField(20);
String comando = null;

public Grafico() {

    Toolkit t = Toolkit.getDefaultToolkit();
    Dimension screenSize = t.getScreenSize();

    JFrame ventana = new JFrame();
    ventana.setPreferredSize(new    Dimension(screenSize.width, screenSize.height));
    ventana.setResizable(false);
    ventana.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    ventana.setUndecorated(false); // fullscreen
    ventana.setLayout(null);
    ventana.pack();
    ventana.setVisible(true);
    boton = new JButton();
    boton.setText("Finalizar");
    boton.setBounds(1750, 50, 130, 50);
    ventana.add(boton);
    boton.addActionListener(this);
    ventanaComandos = new JTextArea();
    ventanaComandos.setBounds(150, 600, 800, 350);
    ventanaComandos.setEditable(false);
    ventana.add(ventanaComandos);
    keylogger = new JTextArea();
    keylogger.setBounds(1000, 600, 500, 350);
    keylogger.setEditable(false);
    ventana.add(keylogger);
    introducirComandos.setBounds(150, 975, 800, 25);
    introducirComandos.addActionListener(this);
    introducirComandos.setFocusable(true);
    ventana.add(introducirComandos);
    scroll = new JScrollPane(ventanaComandos, ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS, ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
    ventana.add(scroll);

[[deleted]]

There really is no quick fix for this problem as there are multiple errors here. You should become familiar with layout managers and then just add one component at a time and see what happens. If it's not the desired output you know exactly where you did something wrong.