Java Erro com ArrayList em Java

[vitao1020]

Estou pegando uma matéria de programação na faculdade que é em java, programação orientada a objetos, tenho que fazer uma agenda de contatos com algumas funções como cadastrar, deletar, alterar, fechar e listar. Consegui fazer o resto das funções exceto a função de listar na qual não estou obtendo exito, no programa em que fiz logo quando crio o contato ele já vai para a lista automaticamente fazendo com que o botão de listar fique inutilizável, assim a lista de contatos fica aparecendo na tela mas queria que a lista aparecesse apenas quando eu apertasse o botão de listar, gostaria de saber se alguém poderia me ajudar com esse problema, segue a parte do código em que tá o arraylist

package Agenda;
import banco.Contato; 

import java.util.ArrayList;
import java.util.List;


public class Agenda_Contato {
    
    private static List<Contato> contatos = new ArrayList<Contato>();

    public static List<Contato> getContatos() {
        return contatos;
    }

    public static void adicionarContato(Contato contato){
        contatos.add(contato);
    }
    
    public static void alterarContato(int linha, Contato contato){
        contatos.set(linha, contato);
    }
    
    public static void deletarContato(Contato contato){
        contatos.remove(contato);
    }
    
    
    
}

 

[iHollyZinhO]

Não sei se entendi direito seu problema, mas deu a entender que está usando interface. Tem como postar o código da interface? Essa parte de mostrar a listagem apenas quando apertar no botão é praticamente dependente do código de criação da interface.

[vitao1020]

@iHollyZinhO essa parte é onde tem a função de listar 

package Agenda.contato;

import banco.Contato;
import java.util.List;
import javax.swing.table.DefaultTableModel;
import Agenda.Agenda_Contato;
import javax.swing.JFrame;
import javax.swing.JOptionPane;

/**
 *
 * @author Lenovo
 */


public class Contatos extends javax.swing.JFrame {
        
    /**
     * Creates new form Contatos
     */
    public static void atualizarTabela(){
        
        
        DefaultTableModel tTabela = (DefaultTableModel) jTable1.getModel();
        tTabela.setNumRows(0);
        
        List<Contato> contatos = Agenda_Contato.getContatos();
        
        for (int linha = 0; linha < contatos.size(); linha++){
            Contato contato = contatos.get(linha);
            tTabela.addRow(new Object[]{1});
            
            jTable1.setValueAt(contato.getCod(), linha, 0);
            jTable1.setValueAt(contato.getNome(), linha, 1);
            jTable1.setValueAt(contato.getTelefone(), linha, 2);
            jTable1.setValueAt(contato.getCelular(), linha, 3);
            jTable1.setValueAt(contato.getEmail(), linha, 4);
        }
    }
    
    public Contatos() {
        initComponents();
        atualizarTabela();
        
    }
    
    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        btnCadastrar = new javax.swing.JButton();
        btnAlterar = new javax.swing.JButton();
        btnDeletar = new javax.swing.JButton();
        jButton1 = new javax.swing.JButton();
        jLabel1 = new javax.swing.JLabel();
        jButton2 = new javax.swing.JButton();
        jToolBar1 = new javax.swing.JToolBar();
        jScrollPane1 = new javax.swing.JScrollPane();
        jTable1 = new javax.swing.JTable();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        btnCadastrar.setText("Cadastrar");
        btnCadastrar.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                btnCadastrarActionPerformed(evt);
            }
        });

        btnAlterar.setText("Alterar");
        btnAlterar.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                btnAlterarActionPerformed(evt);
            }
        });

        btnDeletar.setText("Deletar");
        btnDeletar.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                btnDeletarActionPerformed(evt);
            }
        });

        jButton1.setText("Fechar");
        jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton1ActionPerformed(evt);
            }
        });

        jLabel1.setFont(new java.awt.Font("Tahoma", 0, 14)); // NOI18N
        jLabel1.setForeground(new java.awt.Color(204, 0, 0));
        jLabel1.setText("Listas De Contatos");

        jButton2.setText("Listar");
        jButton2.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton2ActionPerformed(evt);
            }
        });

        jToolBar1.setRollover(true);

        jTable1.setBorder(new javax.swing.border.SoftBevelBorder(javax.swing.border.BevelBorder.RAISED));
        jTable1.setFont(new java.awt.Font("Arial", 0, 12)); // NOI18N
        jTable1.setModel(new javax.swing.table.DefaultTableModel(
            new Object [][] {
                {null, null, null, null, null},
                {null, null, null, null, null},
                {null, null, null, null, null},
                {null, null, null, null, null}
            },
            new String [] {
                "Codigo", "Nome", "Telefone", "Celular", "Email"
            }
        ) {
            Class[] types = new Class [] {
                java.lang.Integer.class, java.lang.String.class, java.lang.Integer.class, java.lang.Integer.class, java.lang.String.class
            };
            boolean[] canEdit = new boolean [] {
                false, false, false, false, false
            };

            public Class getColumnClass(int columnIndex) {
                return types [columnIndex];
            }

            public boolean isCellEditable(int rowIndex, int columnIndex) {
                return canEdit [columnIndex];
            }
        });
        jScrollPane1.setViewportView(jTable1);

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(303, 303, 303)
                .addComponent(jLabel1)
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
            .addGroup(layout.createSequentialGroup()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(layout.createSequentialGroup()
                        .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                            .addComponent(jButton2, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                            .addComponent(btnCadastrar, javax.swing.GroupLayout.DEFAULT_SIZE, 98, Short.MAX_VALUE))
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                        .addComponent(btnAlterar, javax.swing.GroupLayout.PREFERRED_SIZE, 130, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                        .addComponent(btnDeletar, javax.swing.GroupLayout.PREFERRED_SIZE, 130, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                        .addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 130, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(0, 0, Short.MAX_VALUE))
                    .addGroup(layout.createSequentialGroup()
                        .addGap(33, 33, 33)
                        .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 696, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                        .addComponent(jToolBar1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)))
                .addContainerGap())
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(btnCadastrar)
                    .addComponent(btnAlterar)
                    .addComponent(btnDeletar)
                    .addComponent(jButton1))
                .addGap(18, 18, 18)
                .addComponent(jButton2)
                .addGap(13, 13, 13)
                .addComponent(jLabel1)
                .addGap(11, 11, 11)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jToolBar1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 237, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addContainerGap(89, Short.MAX_VALUE))
        );

        pack();
    }// </editor-fold>                        

    private void btnCadastrarActionPerformed(java.awt.event.ActionEvent evt) {                                             
        // TODO add your handling code here:
        JFrame frame = new CadastrarContato();
        frame.setVisible(true);
    }                                            

    private void btnAlterarActionPerformed(java.awt.event.ActionEvent evt) {                                           
        // TODO add your handling code here:
        int linhaSelecionada = jTable1.getSelectedRow();
        
        if(linhaSelecionada >=0){
            JFrame janelaAlterar = new AlterarContato(linhaSelecionada);
            janelaAlterar.setVisible(true);
        }else{
            JOptionPane.showMessageDialog(this, "Selecione um Contato", "Contato",JOptionPane.INFORMATION_MESSAGE );
        }
    }                                          

    private void btnDeletarActionPerformed(java.awt.event.ActionEvent evt) {                                           
        // TODO add your handling code here:
        int linhaSelecionada = jTable1.getSelectedRow();
        
        if(linhaSelecionada >=0){
            int resposta = JOptionPane.showConfirmDialog(this, "Deseja deletar o Contato?");
            if(resposta == JOptionPane.YES_NO_OPTION){
                Contato contato = Agenda_Contato.getContatos().get(linhaSelecionada);
                Agenda_Contato.deletarContato(contato);
                
                atualizarTabela();
            }
        }else{
            JOptionPane.showMessageDialog(this, "Selecione um Contato","Contato",JOptionPane.INFORMATION_MESSAGE);
        }
        
    }                                          

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        // TODO add your handling code here:
        this.dispose();
    }                                        

    private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        // TODO add your handling code here:
        jTable1.setVisible(true);
    }                                        

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /* Set the Nimbus look and feel */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
         * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(Contatos.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(Contatos.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(Contatos.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(Contatos.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>

        /* Create and display the form */
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new Contatos().setVisible(true);
            }
        });
        
    }

    // Variables declaration - do not modify                     
    private javax.swing.JButton btnAlterar;
    private javax.swing.JButton btnCadastrar;
    private javax.swing.JButton btnDeletar;
    private javax.swing.JButton jButton1;
    private javax.swing.JButton jButton2;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JScrollPane jScrollPane1;
    private static javax.swing.JTable jTable1;
    private javax.swing.JToolBar jToolBar1;
    // End of variables declaration                   
}

 

adicionado 0 minutos depois

@iHollyZinhO e essa parte é onde eu cadastro o contato 

package Agenda.contato;

import Agenda.Agenda_Contato;
import banco.Contato;



/**
 *
 * @author Lenovo
 */
public class AlterarContato extends javax.swing.JFrame {

    /**
     * Creates new form CadastrarContato
     */
    
    private Contato contato;
    private int linhaSelecionada;
    
    public AlterarContato() {
        initComponents();
    }
    
    public AlterarContato(int linhaSelecionada){
        initComponents();
        
        this.linhaSelecionada = linhaSelecionada;
        contato = Agenda_Contato.getContatos().get(linhaSelecionada);
        txtCodigo.setText(String.valueOf(contato.getCod()));
        txtNome.setText(String.valueOf(contato.getNome()));
        txtTelefone.setText(String.valueOf(contato.getTelefone()));
        txtCelular.setText(String.valueOf(contato.getCelular()));
        txtEmail.setText(String.valueOf(contato.getEmail()));
    }
    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        jLabel1 = new javax.swing.JLabel();
        jLabel2 = new javax.swing.JLabel();
        jLabel3 = new javax.swing.JLabel();
        jLabel4 = new javax.swing.JLabel();
        jLabel5 = new javax.swing.JLabel();
        txtCodigo = new javax.swing.JTextField();
        txtNome = new javax.swing.JTextField();
        txtTelefone = new javax.swing.JTextField();
        txtCelular = new javax.swing.JTextField();
        txtEmail = new javax.swing.JTextField();
        btnCancelar = new javax.swing.JButton();
        btnConfirmar = new javax.swing.JButton();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jLabel1.setFont(new java.awt.Font("Tahoma", 0, 12)); // NOI18N
        jLabel1.setText("Codigo: ");

        jLabel2.setFont(new java.awt.Font("Tahoma", 0, 12)); // NOI18N
        jLabel2.setText("Nome:");

        jLabel3.setFont(new java.awt.Font("Tahoma", 0, 12)); // NOI18N
        jLabel3.setText("Telefone: ");

        jLabel4.setFont(new java.awt.Font("Tahoma", 0, 12)); // NOI18N
        jLabel4.setText("Celular:");

        jLabel5.setFont(new java.awt.Font("Tahoma", 0, 12)); // NOI18N
        jLabel5.setText("E-mail:");

        btnCancelar.setText("Cancelar");
        btnCancelar.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                btnCancelarActionPerformed(evt);
            }
        });

        btnConfirmar.setText("Confirmar");
        btnConfirmar.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                btnConfirmarActionPerformed(evt);
            }
        });

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap(32, Short.MAX_VALUE)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                    .addComponent(jLabel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                    .addComponent(jLabel2, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                    .addComponent(jLabel3, javax.swing.GroupLayout.DEFAULT_SIZE, 91, Short.MAX_VALUE)
                    .addComponent(jLabel4, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                    .addComponent(jLabel5, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
                .addGap(18, 18, 18)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING, false)
                    .addGroup(layout.createSequentialGroup()
                        .addComponent(btnConfirmar, javax.swing.GroupLayout.PREFERRED_SIZE, 95, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 36, Short.MAX_VALUE)
                        .addComponent(btnCancelar, javax.swing.GroupLayout.PREFERRED_SIZE, 95, javax.swing.GroupLayout.PREFERRED_SIZE))
                    .addComponent(txtCodigo, javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(txtNome, javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(txtTelefone, javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(txtCelular, javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(txtEmail, javax.swing.GroupLayout.Alignment.LEADING, javax.swing.GroupLayout.DEFAULT_SIZE, 226, Short.MAX_VALUE))
                .addContainerGap(33, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(45, 45, 45)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 27, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(txtCodigo, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel2, javax.swing.GroupLayout.PREFERRED_SIZE, 27, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(txtNome, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel3, javax.swing.GroupLayout.PREFERRED_SIZE, 27, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(txtTelefone, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel4, javax.swing.GroupLayout.PREFERRED_SIZE, 27, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(txtCelular, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(13, 13, 13)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel5, javax.swing.GroupLayout.PREFERRED_SIZE, 27, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(txtEmail, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 32, Short.MAX_VALUE)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(btnConfirmar)
                    .addComponent(btnCancelar))
                .addGap(19, 19, 19))
        );

        pack();
    }// </editor-fold>                        

    private void btnConfirmarActionPerformed(java.awt.event.ActionEvent evt) {                                             
        // TODO add your handling code here:
        int iCodigo = Integer.parseInt(txtCodigo.getText());
        String iNome = txtNome.getText();
        long iTelefone = Long.parseLong(txtTelefone.getText());
        long iCelular = Long.parseLong(txtCelular.getText());
        String iemail = txtEmail.getText();
        
        Contato contato = new Contato();
        contato.setCod(iCodigo);
        contato.setNome(iNome);
        contato.setTelefone(iTelefone);
        contato.setCelular(iCelular);
        contato.setEmail(iemail);
        
        Agenda_Contato.alterarContato(linhaSelecionada, contato);
        Contatos.atualizarTabela();
        this.dispose();  
        
    }                                            

    private void btnCancelarActionPerformed(java.awt.event.ActionEvent evt) {                                            
        // TODO add your handling code here:
        this.dispose();
    }                                           

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /* Set the Nimbus look and feel */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
         * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(AlterarContato.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(AlterarContato.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(AlterarContato.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(AlterarContato.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>
        //</editor-fold>

        /* Create and display the form */
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new AlterarContato().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    private javax.swing.JButton btnCancelar;
    private javax.swing.JButton btnConfirmar;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JLabel jLabel3;
    private javax.swing.JLabel jLabel4;
    private javax.swing.JLabel jLabel5;
    private javax.swing.JTextField txtCelular;
    private javax.swing.JTextField txtCodigo;
    private javax.swing.JTextField txtEmail;
    private javax.swing.JTextField txtNome;
    private javax.swing.JTextField txtTelefone;
    // End of variables declaration                   
}

 

[iHollyZinhO]

Você pode alternar a visibilidade do componente jTable1 no ActionListener do botão de listar, por exemplo:

 

jButton2.addActionListener(new ActionListener()
{
	public void actionPerformed(ActionEvent arg0) 
	{
		jTable1.setVisible(!jTable1.isVisible());
	}
});

 

Como você está usando a tabela dentro de um JScrollPane, o cabeçalho da tabela pode não sumir, então você deve usar o setVisible no próprio JScrollPane e não na tabela.

[vitao1020]

@iHollyZinhO implementei isso ao código mas agora a lista fica "invisível" e não aparece nem quando eu aperto o botão de listar