Text Area com Scroll (chat)

Programação Java
#1

Estou com o seguinte problema… quero fazer uma tela de chat que va baixando conforme as mensagens vao chegando. Porém o scroll vertical nao aparece… segue o trecho de codigo

private JTextArea getJTextAreaChat() {
		
		chat = new JPanel();  
        scrollPane = new JScrollPane(jTextAreaChat);  
        chat.add(scrollPane);  
        scrollPane.setBounds(19, 38, 391, 470);  
        
        
		if (jTextAreaChat == null) {
			jTextAreaChat = new JTextArea();
			jTextAreaChat.setLineWrap(true);
			scrollPane.setViewportView(jTextAreaChat); 
		    jTextAreaChat.setBounds(new Rectangle(19, 38, 391, 470));
			jTextAreaChat.setEditable(false);
			jTextAreaChat.setBackground(this.white);
		}
		return jTextAreaChat;
	}
#2

Que estranho. Dá uma olhadinha nesse exemplo que montei e vê se ajuda:

[code]import javax.swing.;
import java.awt.;
import java.awt.event.*;

public class Scroll extends JFrame {

JScrollPane scroll;
JTextArea area;
JTextField field;
JButton btn;

public Scroll() {
    area = new JTextArea(10, 15);
    scroll = new JScrollPane(area);

    add(scroll, BorderLayout.CENTER);

    field = new JTextField(20);
    btn = new JButton("Add"); 
    
    JPanel pnl = new JPanel();

    pnl.add(field);
    pnl.add(btn);

    add(pnl, BorderLayout.SOUTH);      

    btn.addActionListener(new ActionListener() {

        public void actionPerformed(ActionEvent e) {
            area.setText(area.getText() + field.getText() + "\n");
        }
    });
    
    pack();
    setLocationRelativeTo(null);
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    setVisible(true);
}

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

}[/code]

T+

#3

Nao consigo fazer o scroll funcionar! Alguma dica?

[code]package gui;

import javax.swing.;
import javax.swing.border.EtchedBorder;
import java.awt.;
import java.awt.event.KeyEvent;

public class principalFrame extends JFrame {

private JMenuBar BarraMenu = null;  
private JMenu mnuArquivo = null;  
private JMenuItem mnuSair = null;

// private JTextField tf_usuario = null;

private static final long serialVersionUID = 1L;
private JPanel jContentPane = null;
private JTextField jTextFieldChat = null;
private JButton jButtonChat = null;

// private JPanel chat;

private FreeHand jPanelFree = new FreeHand();  //  @jve:decl-index=0:visual-constraint="119,620"

private static principalFrame executa;
private JButton jButtonEnviarDraw = null;

// private JLabel jLabel = null;
private JTextArea areaChat = null;
private Color white = new Color(255,255,255); // @jve:decl-index=0:
private JComboBox jComboBoxUsuarios = null;

/*private ArrayList messages = new ArrayList();*/  //  @jve:decl-index=0:

//garante apenas uma unica instancia na memoria
static{
	executa = new principalFrame();
}


/** Construtor Default **/
public principalFrame() {
	super();
	setVisible(false);
}


	private void initialize() {
	
	//finaliza a janela de login
	loginFrame.getInstance().finish();
	
	jPanelFree.setSize(new Dimension(367, 498));
	jPanelFree.setBorder(BorderFactory.createEtchedBorder(EtchedBorder.RAISED));
	jPanelFree.setLocation(new Point(418, 10));
	this.setSize(800, 600);
	this.setContentPane(getJContentPane());
	this.setJMenuBar(getBarraMenu());  
	this.setTitle("DrawChat - Ferramenta de Ensino a Distancia");
	executa.setVisible(true);
	executa.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
	executa.setLocation(100,100);
	add(scroll, BorderLayout.CENTER);
	
	
}

	private JMenuBar getBarraMenu() {  
		         if (BarraMenu == null){  
		             BarraMenu = new JMenuBar();  
		             BarraMenu.add(getMnuArquivo());  
		         }  
		         return BarraMenu;  
	}  
	private JMenu getMnuArquivo() {  
		         if (mnuArquivo == null){  
		             mnuArquivo = new JMenu();  
		             mnuArquivo.setText("Arquivo");  
		             mnuArquivo.add(getMnuSair());  
		         }  
		         return mnuArquivo;  
		     }  
	

	private JMenuItem getMnuSair() {  
		         if (mnuSair == null){  
		             mnuSair = new JMenuItem();  
		             mnuSair.setText("Sair");  
		             mnuSair.setMnemonic(KeyEvent.VK_S);
		 			 mnuSair.addActionListener(new java.awt.event.ActionListener() {
						public void actionPerformed(java.awt.event.ActionEvent e) {
							System.exit(0);
						}
					});
		         }  
		         return mnuSair;  
		     }  
	
	public static principalFrame getInstance()
	{
		return executa;
	}
	
	public void openPrincipal()
	{
		initialize();
	}

		
private JPanel getJContentPane() {
	
	if (jContentPane == null) {
		
		//jLabel = new JLabel();
		//jLabel.setBounds(new java.awt.Rectangle(0,-2,792,542));
		//jLabel.setFont(new Font("Dialog", Font.BOLD, 36));
		//jLabel.setIcon(new ImageIcon(getClass().getResource("/gui/background.jpg")));
		//jLabel.setText("Background");
		jContentPane = new JPanel();
		jContentPane.setLayout(null);
		jContentPane.add(getJTextFieldChat(), null);
		jContentPane.add(getJButtonChat(), null);
		jContentPane.add(getJPanel_Free(), null);
		jContentPane.add(getJButtonEnviarDraw(), null);
		jContentPane.add(getJTextAreaChat(), null);
		//jContentPane.add(jLabel, null);
		jContentPane.add(getJComboBoxUsuarios(), null);
		jContentPane.add(scroll, BorderLayout.CENTER);
		
		
	}
	return jContentPane;
}

/**
 * This method initializes jTextFieldChat	
 * 	
 * @return javax.swing.JTextField	
 */
private JTextField getJTextFieldChat() {
	if (jTextFieldChat == null) {
		jTextFieldChat = new JTextField();
		jTextFieldChat.setBounds(new Rectangle(17, 510, 340, 23));
	}
	return jTextFieldChat;
}


private JButton getJButtonChat() {
	if (jButtonChat == null) {
		jButtonChat = new JButton();
		jButtonChat.setBounds(new Rectangle(358, 510, 52, 23));
		jButtonChat.setText("Ok");
		jButtonChat.addActionListener(new java.awt.event.ActionListener() {
			public void actionPerformed(java.awt.event.ActionEvent e) {
				enviaMensagem();
				
			}
		});
	}
	return jButtonChat;
}


private void enviaMensagem(){
	String mensagem = this.jTextFieldChat.getText();
	if(mensagem.equals("")){}
	else{
		//addMessage(mensagem);
		String nick = loginFrame.user.getNick();
		String texto = nick+": "+mensagem;
		

		
		if(areaChat.getText().equals("")){
			areaChat.setText(texto);
			jTextFieldChat.setText("");
		
		}else{
		
			areaChat.setText(areaChat.getText()+"\n"+texto);
		jTextFieldChat.setText("");
		
		}
	}
}

private FreeHand getJPanel_Free(){
	if(jPanelFree == null){
		jPanelFree.setBounds(new Rectangle(0,0,100,100));
	}
	
	return jPanelFree;
}


/**
 * This method initializes jButtonEnviarDraw	
 * 	
 * @return javax.swing.JButton	
 */
private JButton getJButtonEnviarDraw() {
	if (jButtonEnviarDraw == null) {
		jButtonEnviarDraw = new JButton();
		jButtonEnviarDraw.setBounds(new Rectangle(715, 510, 70, 23));
		jButtonEnviarDraw.setText("Enviar");
	}
	return jButtonEnviarDraw;
}

JScrollPane scroll = new JScrollPane(areaChat);


private JTextArea getJTextAreaChat() {

    
	if (areaChat == null) {
		add(scroll, BorderLayout.CENTER);
		areaChat = new JTextArea();
		areaChat.setLineWrap(true);
		areaChat.setAutoscrolls(true);
		areaChat.setLayout(null); 
		areaChat.setEditable(false);
		areaChat.setBounds(new Rectangle(19, 38, 391, 470));
		areaChat.setBackground(this.white);
		setLocationRelativeTo(null);  
		setVisible(true);
	
	}
	return areaChat;
}



/**
 * This method initializes jComboBoxUsuarios	
 * 	
 * @return javax.swing.JComboBox	
 */
private JComboBox getJComboBoxUsuarios() {
	if (jComboBoxUsuarios == null) {
		jComboBoxUsuarios = new JComboBox();
		jComboBoxUsuarios.setBounds(new Rectangle(18, 10, 393, 25));
		jComboBoxUsuarios.setMaximumRowCount(10);
		jComboBoxUsuarios.addItem("");
		listaUsuarios();
		jComboBoxUsuarios.addActionListener(new java.awt.event.ActionListener() {
			public void actionPerformed(java.awt.event.ActionEvent e) {
				selecionaUsuarios();
			}
		});
	}
	return jComboBoxUsuarios;
}

private void selecionaUsuarios()
{
	if(this.jComboBoxUsuarios.getSelectedItem().equals(loginFrame.user.getNick()))
	{
		String usuario = loginFrame.user.getNick();
		JOptionPane.showMessageDialog(this,"Usuário selecionado: "+usuario, "",JOptionPane.INFORMATION_MESSAGE);
		/*Usuario usuarios = (Usuario)this.jComboBoxUsuarios.getSelectedItem();
		tf_usuario.setText(usuarios.getNick());
		jComboBoxUsuarios.setSelectedItem(String.valueOf(usuarios.getNick()));
		tf_usuario.setEnabled(false);*/
					
				}
}
	
private void listaUsuarios(){
	String user = loginFrame.user.getNick();
	this.jComboBoxUsuarios.addItem(user);
	
}
	

/*public void addMessage(String msg) {
messages.add(msg);
synchronized (messages) {
    // sinaliza para quem está esperando
    messages.notifyAll();

}
}*/

}[/code]

#4