Jcombox com opção nula ? Como que faz?

As primeiras opções para Fabricante, Voltagem e Série tem que ser valor nulo para a JOptiopane
String auxFabricante = (String) comboFabricante.getSelectedItem();
String auxVoltagem = (String) comboVoltagem.getSelectedItem();
String auxSerie = (String) comboSerie.getSelectedItem();

1 curtida

Obrigado ai, eu fiz aqui e não alterou em nada

mostra

1 curtida

Eu fiz assim, selecione uma das opções e coloquei vazio pelo botão mesmo.

mostra o código

1 curtida
package trabalho1PoeNivaldo;

import javax.swing.JOptionPane;

public class TelaLogin extends javax.swing.JFrame {

    public TelaLogin() {
        initComponents();

    }

    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        jPanel1 = new javax.swing.JPanel();
        jLabel1 = new javax.swing.JLabel();
        jLabel3 = new javax.swing.JLabel();
        jLabel5 = new javax.swing.JLabel();
        campoNome = new javax.swing.JTextField();
        campoSenha = new javax.swing.JPasswordField();
        jLabel4 = new javax.swing.JLabel();
        campoConfirmacaoSenha = new javax.swing.JTextField();
        jLabel2 = new javax.swing.JLabel();
        campoLogin = new javax.swing.JTextField();
        checkUsuario = new javax.swing.JCheckBox();
        checkTI = new javax.swing.JCheckBox();
        checkSupervisor = new javax.swing.JCheckBox();
        checkConsultor = new javax.swing.JCheckBox();
        jLabel6 = new javax.swing.JLabel();
        comboSetor = new javax.swing.JComboBox<>();
        jLabel7 = new javax.swing.JLabel();
        campoEmail = new javax.swing.JTextField();
        botaoEntrar = new javax.swing.JButton();
        botaoLimpar = new javax.swing.JButton();
        botaoSair = new javax.swing.JButton();
        jLabel8 = new javax.swing.JLabel();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        setTitle("TELA DE LOGIN");
        setResizable(false);

        javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
        jPanel1.setLayout(jPanel1Layout);
        jPanel1Layout.setHorizontalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
            .addGap(0, 3, Short.MAX_VALUE)
        );
        jPanel1Layout.setVerticalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 333, Short.MAX_VALUE)
        );

        jLabel1.setFont(new java.awt.Font("Times New Roman", 0, 13)); // NOI18N
        jLabel1.setForeground(new java.awt.Color(0, 153, 51));
        jLabel1.setText("Nome:");

        jLabel3.setFont(new java.awt.Font("Times New Roman", 0, 13)); // NOI18N
        jLabel3.setForeground(new java.awt.Color(0, 153, 51));
        jLabel3.setText("Senha:");

        jLabel5.setForeground(new java.awt.Color(0, 153, 51));
        jLabel5.setText("Nivel de Acesso:");
        jLabel5.setMaximumSize(new java.awt.Dimension(70, 25));
        jLabel5.setMinimumSize(new java.awt.Dimension(70, 25));

        jLabel4.setForeground(new java.awt.Color(0, 153, 51));
        jLabel4.setText("Confirmação de Senha:");

        jLabel2.setFont(new java.awt.Font("Times New Roman", 0, 13)); // NOI18N
        jLabel2.setForeground(new java.awt.Color(0, 153, 51));
        jLabel2.setText("Login:");

        checkUsuario.setForeground(new java.awt.Color(0, 153, 51));
        checkUsuario.setText("Usuário");
        checkUsuario.setMaximumSize(new java.awt.Dimension(70, 25));
        checkUsuario.setMinimumSize(new java.awt.Dimension(70, 25));

        checkTI.setForeground(new java.awt.Color(0, 153, 51));
        checkTI.setText("T.I");
        checkTI.setPreferredSize(new java.awt.Dimension(70, 25));

        checkSupervisor.setForeground(new java.awt.Color(0, 153, 51));
        checkSupervisor.setText("Supervisor");
        checkSupervisor.setMaximumSize(new java.awt.Dimension(70, 25));
        checkSupervisor.setMinimumSize(new java.awt.Dimension(70, 25));

        checkConsultor.setForeground(new java.awt.Color(0, 153, 51));
        checkConsultor.setText("Consultor");
        checkConsultor.setMaximumSize(new java.awt.Dimension(70, 25));
        checkConsultor.setMinimumSize(new java.awt.Dimension(70, 25));

        jLabel6.setForeground(new java.awt.Color(0, 153, 51));
        jLabel6.setText("Setor:");

        comboSetor.setForeground(new java.awt.Color(0, 153, 51));
        comboSetor.setModel(new javax.swing.DefaultComboBoxModel<>(new String[] { "<<selecione uma opcao>>", " ", "Administrativo", "Gestão", "Protocolo", " " }));
        comboSetor.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                comboSetorActionPerformed(evt);
            }
        });

        jLabel7.setForeground(new java.awt.Color(0, 153, 51));
        jLabel7.setText("Email:");

        botaoEntrar.setText("ENTRAR");
        botaoEntrar.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                botaoEntrarActionPerformed(evt);
            }
        });

        botaoLimpar.setText("LIMPAR");
        botaoLimpar.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                botaoLimparActionPerformed(evt);
            }
        });

        botaoSair.setText("SAIR");
        botaoSair.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                botaoSairActionPerformed(evt);
            }
        });

        jLabel8.setFont(new java.awt.Font("Times New Roman", 0, 24)); // NOI18N
        jLabel8.setForeground(new java.awt.Color(255, 0, 0));
        jLabel8.setText("          TELA DE LOGIN");

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(layout.createSequentialGroup()
                        .addGap(20, 20, 20)
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                            .addGroup(layout.createSequentialGroup()
                                .addGap(222, 222, 222)
                                .addComponent(checkTI, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                                .addGap(18, 18, 18)
                                .addComponent(checkSupervisor, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                                .addGap(0, 0, Short.MAX_VALUE))
                            .addGroup(layout.createSequentialGroup()
                                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                                    .addComponent(jLabel1)
                                    .addComponent(jLabel3))
                                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                                    .addGroup(layout.createSequentialGroup()
                                        .addComponent(campoSenha, javax.swing.GroupLayout.PREFERRED_SIZE, 160, javax.swing.GroupLayout.PREFERRED_SIZE)
                                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                                        .addComponent(jLabel4))
                                    .addComponent(campoNome, javax.swing.GroupLayout.PREFERRED_SIZE, 315, javax.swing.GroupLayout.PREFERRED_SIZE))
                                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                                    .addGroup(layout.createSequentialGroup()
                                        .addComponent(jLabel2, javax.swing.GroupLayout.PREFERRED_SIZE, 41, javax.swing.GroupLayout.PREFERRED_SIZE)
                                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                                        .addComponent(campoLogin, javax.swing.GroupLayout.PREFERRED_SIZE, 152, javax.swing.GroupLayout.PREFERRED_SIZE))
                                    .addComponent(campoConfirmacaoSenha))
                                .addGap(13, 13, 13))))
                    .addGroup(layout.createSequentialGroup()
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                            .addGroup(layout.createSequentialGroup()
                                .addContainerGap()
                                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                                    .addGroup(layout.createSequentialGroup()
                                        .addGap(6, 6, 6)
                                        .addComponent(jLabel6, javax.swing.GroupLayout.PREFERRED_SIZE, 36, javax.swing.GroupLayout.PREFERRED_SIZE)
                                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                                        .addComponent(comboSetor, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                                        .addComponent(jLabel7)
                                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                                        .addComponent(campoEmail, javax.swing.GroupLayout.PREFERRED_SIZE, 286, javax.swing.GroupLayout.PREFERRED_SIZE))
                                    .addGroup(layout.createSequentialGroup()
                                        .addComponent(jLabel5, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                                        .addGap(18, 18, 18)
                                        .addComponent(checkUsuario, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                                        .addGap(263, 263, 263)
                                        .addComponent(checkConsultor, javax.swing.GroupLayout.PREFERRED_SIZE, 140, javax.swing.GroupLayout.PREFERRED_SIZE))))
                            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                                .addGap(28, 28, 28)
                                .addComponent(botaoEntrar)
                                .addGap(155, 155, 155)
                                .addComponent(botaoLimpar)
                                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                                .addComponent(botaoSair)
                                .addGap(18, 18, 18)))
                        .addGap(0, 6, Short.MAX_VALUE))
                    .addGroup(layout.createSequentialGroup()
                        .addGap(137, 137, 137)
                        .addComponent(jLabel8, javax.swing.GroupLayout.PREFERRED_SIZE, 322, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)))
                .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(layout.createSequentialGroup()
                        .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                        .addContainerGap())
                    .addGroup(layout.createSequentialGroup()
                        .addComponent(jLabel8, javax.swing.GroupLayout.PREFERRED_SIZE, 35, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(29, 29, 29)
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                            .addComponent(jLabel1)
                            .addComponent(campoNome, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addComponent(jLabel2)
                            .addComponent(campoLogin, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                        .addGap(18, 18, 18)
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                            .addComponent(jLabel3)
                            .addComponent(campoSenha)
                            .addComponent(jLabel4, javax.swing.GroupLayout.PREFERRED_SIZE, 22, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addComponent(campoConfirmacaoSenha, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                        .addGap(29, 29, 29)
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                            .addComponent(jLabel5, javax.swing.GroupLayout.PREFERRED_SIZE, 25, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addComponent(checkUsuario, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addComponent(checkTI, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addComponent(checkSupervisor, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addComponent(checkConsultor, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                            .addComponent(jLabel6)
                            .addComponent(comboSetor, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addComponent(jLabel7, javax.swing.GroupLayout.PREFERRED_SIZE, 22, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addComponent(campoEmail, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                        .addGap(53, 53, 53)
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                            .addComponent(botaoEntrar)
                            .addComponent(botaoLimpar)
                            .addComponent(botaoSair))
                        .addGap(39, 39, 39))))
        );

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

    private void botaoEntrarActionPerformed(java.awt.event.ActionEvent evt) {                                            
        new TelaLogin().setVisible(true);

        JOptionPane.showMessageDialog(null, "Preencha todos os campos!");

        if (campoSenha.getText().equals("Usuario") && campoConfirmacaoSenha.getText().equals("Usuario")) {

            String auxNome = campoNome.getText();

            String auxNivel = "";
            if (checkUsuario.isSelected()) {
                auxNivel += "Usuario ";
            }
            if (checkTI.isSelected()) {
                auxNivel += "TI";
            }
            if (checkSupervisor.isSelected()) {
                auxNivel += "Supervisor";
            }
            if (checkConsultor.isSelected()) {
                auxNivel += "Consultor ";
            }
            String auxSetor = (String) comboSetor.getSelectedItem();
 
            String auxEmail = campoEmail.getText();

            JOptionPane.showMessageDialog(null, "Acesso Permitido" + "\nNome:" + auxNome
                    + "\nNivel de acesso:" + auxNivel + "\nEmail:" + auxEmail + "\nSetor:" + auxSetor + "\n Seja Bem Vindo!");
        } else {
            JOptionPane.showMessageDialog(null, "Senhas Diferentes! Insira senhas iguais");
        }

    }                                           

    private void comboSetorActionPerformed(java.awt.event.ActionEvent evt) {                                           

    }                                          

    private void botaoSairActionPerformed(java.awt.event.ActionEvent evt) {                                          
        System.exit(0);
    }                                         

    private void botaoLimparActionPerformed(java.awt.event.ActionEvent evt) {                                            

        campoConfirmacaoSenha.setText("");

    }                                           

    /**
     * @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(TelaLogin.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(TelaLogin.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(TelaLogin.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(TelaLogin.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>
        //</editor-fold>
        //</editor-fold>
        //</editor-fold>
        //</editor-fold>
        //</editor-fold>
        //</editor-fold>
        //</editor-fold>

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

    // Variables declaration - do not modify                     
    private javax.swing.JButton botaoEntrar;
    private javax.swing.JButton botaoLimpar;
    private javax.swing.JButton botaoSair;
    private javax.swing.JTextField campoConfirmacaoSenha;
    private javax.swing.JTextField campoEmail;
    private javax.swing.JTextField campoLogin;
    private javax.swing.JTextField campoNome;
    private javax.swing.JPasswordField campoSenha;
    private javax.swing.JCheckBox checkConsultor;
    private javax.swing.JCheckBox checkSupervisor;
    private javax.swing.JCheckBox checkTI;
    private javax.swing.JCheckBox checkUsuario;
    public javax.swing.JComboBox<String> comboSetor;
    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.JLabel jLabel6;
    private javax.swing.JLabel jLabel7;
    private javax.swing.JLabel jLabel8;
    private javax.swing.JPanel jPanel1;
    // End of variables declaration                   

}

Mas onde vc ta adicionando os itens na JComboBox?

1 curtida

Acho q vc colocou manualmente, vai em Design, e nas propriedades da JComboBox, tem alguma coisa do tipo: “Selected Index”, vai ter um valor 0, só trocar por -1.

Senão tiver essa opção, tira print das propriedades

1 curtida

fiz isso que você falou, ele tirou as opções.

Manda o print da tela do netbeans aí, das propriedades

1 curtida

Na verdade, não mudou nada

tá certo, outra opção é no initComponents vc setar o

suaComboBox.setSelectedItem(null);

ou

suaComboBox.setSelectedIndex(-1);
1 curtida

Obrigado, me desculpa demorar responder estava no banho e jantando, cara tenho outra dúvida, é sobre a mensagem a ser exibida, depois que eu preencher os dados. Eu tenho que exibir a mensagem: " Preencha todos os Campos" , eu usei o JOptionpane, só que o meu programa, tá dando a mesma resposta com os campos totalmente preenchidos. Onde eu terei que mudar, e como limpar esta mensagem ?

if (seuComboBox.getSelectedItem() == null) {
    JOptionPane.showMessageDialog(null, "Por favor, selecione algum item");
} else {
    //deixa salvar
}

Não é ai não, é no programa em Geral, agora deu certo, obrigado ai .