我一直在尝试将值添加到来自单独jFrame的类中的列表中。我进行了测试，知道该信息可以正确发送，并且接收该信息的功能也可以正确接收它。问题是我不确定是否将信息添加到列表中，因为当我尝试打印信息时，什么也没发生。
import java.util.ArrayList;
public class Conta {
private int NumConta;
private String Nome;
private String RG;
private String CPF;
private double Saldo;
private String Password;
ArrayList<Conta> ListaUser;
public Conta(){
ListaUser = new ArrayList();
}
public Conta(int NumConta, String Nome, String RG, String CPF, double Saldo, String Password) {
this.NumConta = NumConta;
this.Nome = Nome;
this.RG = RG;
this.CPF = CPF;
this.Saldo = Saldo;
this.Password = Password;
ListaUser = new ArrayList();
}
public int getNumConta() {
return NumConta;
}
public void setNumConta(int NumConta) {
this.NumConta = NumConta;
}
public String getNome() {
return Nome;
}
public void setNome(String Nome) {
this.Nome = Nome;
}
public String getRG() {
return RG;
}
public void setRG(String RG) {
this.RG = RG;
}
public String getCPF() {
return CPF;
}
public void setCPF(String CPF) {
this.CPF = CPF;
}
public double getSaldo() {
return Saldo;
}
public void setSaldo(double Saldo) {
this.Saldo = Saldo;
}
public String getPassword() {
return Password;
}
public void setPassword(String Password) {
this.Password = Password;
}
public ArrayList<Conta> getListaUser() {
return ListaUser;
}
public void setListaUser(ArrayList<Conta> ListaUser) {
this.ListaUser = ListaUser;
}
public void AddFunc(Conta C){
ListaUser.add(C);
}
}
这是接收信息的班级
import java.util.Random;
import javax.swing.JOptionPane;
public class Cadastrar extends javax.swing.JFrame {
public Cadastrar() {
initComponents();
}
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jPanelinicio = new javax.swing.JPanel();
jPanel2 = new javax.swing.JPanel();
jLabel1 = new javax.swing.JLabel();
jLabel2 = new javax.swing.JLabel();
jLabel3 = new javax.swing.JLabel();
jLabel4 = new javax.swing.JLabel();
jTextFieldnomecadastro = new javax.swing.JTextField();
jTextFieldRG = new javax.swing.JTextField();
jTextFieldCPF = new javax.swing.JTextField();
jTextFieldpasswordcadastro = new javax.swing.JTextField();
jButtonconfirmarcadastro = new javax.swing.JButton();
jButtonvoltarCadastrar = new javax.swing.JButton();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jPanelinicio.setBackground(new java.awt.Color(102, 153, 255));
jPanel2.setBackground(new java.awt.Color(255, 255, 255));
jLabel1.setText("RG:");
jLabel2.setText("CPF:");
jLabel3.setText("Nome:");
jLabel4.setText("Password:");
jButtonconfirmarcadastro.setText("Confirmar");
jButtonconfirmarcadastro.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButtonconfirmarcadastroActionPerformed(evt);
}
});
jButtonvoltarCadastrar.setText("Voltar");
jButtonvoltarCadastrar.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButtonvoltarCadastrarActionPerformed(evt);
}
});
javax.swing.GroupLayout jPanel2Layout = new javax.swing.GroupLayout(jPanel2);
jPanel2.setLayout(jPanel2Layout);
jPanel2Layout.setHorizontalGroup(
jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel2Layout.createSequentialGroup()
.addContainerGap()
.addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jLabel3)
.addComponent(jLabel1)
.addComponent(jLabel2)
.addComponent(jLabel4))
.addGap(58, 58, 58)
.addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jTextFieldpasswordcadastro, javax.swing.GroupLayout.PREFERRED_SIZE, 255, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jTextFieldCPF, javax.swing.GroupLayout.PREFERRED_SIZE, 255, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jTextFieldRG, javax.swing.GroupLayout.PREFERRED_SIZE, 255, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jTextFieldnomecadastro, javax.swing.GroupLayout.PREFERRED_SIZE, 255, javax.swing.GroupLayout.PREFERRED_SIZE))
.addContainerGap(77, Short.MAX_VALUE))
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel2Layout.createSequentialGroup()
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addComponent(jButtonconfirmarcadastro, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(jButtonvoltarCadastrar, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
.addGap(173, 173, 173))
);
jPanel2Layout.setVerticalGroup(
jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel2Layout.createSequentialGroup()
.addGap(56, 56, 56)
.addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel3)
.addComponent(jTextFieldnomecadastro, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(47, 47, 47)
.addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel1)
.addComponent(jTextFieldRG, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(43, 43, 43)
.addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel2)
.addComponent(jTextFieldCPF, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(40, 40, 40)
.addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(jLabel4)
.addComponent(jTextFieldpasswordcadastro, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(68, 68, 68)
.addComponent(jButtonconfirmarcadastro)
.addGap(18, 18, 18)
.addComponent(jButtonvoltarCadastrar)
.addContainerGap(28, Short.MAX_VALUE))
);
javax.swing.GroupLayout jPanelinicioLayout = new javax.swing.GroupLayout(jPanelinicio);
jPanelinicio.setLayout(jPanelinicioLayout);
jPanelinicioLayout.setHorizontalGroup(
jPanelinicioLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jPanel2, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
);
jPanelinicioLayout.setVerticalGroup(
jPanelinicioLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanelinicioLayout.createSequentialGroup()
.addGap(0, 117, Short.MAX_VALUE)
.addComponent(jPanel2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jPanelinicio, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jPanelinicio, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
);
pack();
setLocationRelativeTo(null);
}// </editor-fold>
private void jButtonvoltarCadastrarActionPerformed(java.awt.event.ActionEvent evt) {
Principal principal = new Principal();
principal.setVisible(true);
dispose();
}
private void jButtonconfirmarcadastroActionPerformed(java.awt.event.ActionEvent evt) {
Random random = new Random();
int numero = random.nextInt(9999999);
Conta C = new Conta(numero,jTextFieldnomecadastro.getText(),jTextFieldRG.getText(),jTextFieldCPF.getText(),0,jTextFieldpasswordcadastro.getText());
C.AddFunc(C);
JOptionPane.showMessageDialog(this, "Conta criada com sucesso!\n"+"Numero da conta: "+numero);
Principal p = new Principal();
p.setVisible(true);
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(Cadastrar.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(Cadastrar.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(Cadastrar.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(Cadastrar.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 Cadastrar().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton jButtonconfirmarcadastro;
private javax.swing.JButton jButtonvoltarCadastrar;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JLabel jLabel3;
private javax.swing.JLabel jLabel4;
private javax.swing.JPanel jPanel2;
private javax.swing.JPanel jPanelinicio;
private javax.swing.JTextField jTextFieldCPF;
private javax.swing.JTextField jTextFieldRG;
private javax.swing.JTextField jTextFieldnomecadastro;
private javax.swing.JTextField jTextFieldpasswordcadastro;
// End of variables declaration
}
此jFrame发送信息。
如何使列表接收信息，以及如何查看所有添加的信息？
预先感谢
答案 0 :(得分：1)
每个Conta都有它自己的ListaUser副本，所以当您这样做时
Conta C = new Conta(...);
C.AddFunc(C);
您正在将C添加到 C自己的ListaUser副本中，并且每个Conta C将包含一个列表ListaUser，该列表中只有一个元素； C本身。换句话说，每个Conta都将有一个列表，仅其自身为列表内容。没有包含您创建的Conta的所有所有的列表。
帐户（Conta）不应是维护程序所保留帐户列表的地方。程序本身与帐户有关，因此该程序具有一个帐户列表。
public class Cadastrar extends javax.swing.JFrame {
private List<Conta> listaUser = new ArrayList<>();
private Cadastrar program;
public Cadastrar() {
initComponents();
program = this;
}
// etc.
以后在jButtonconfirmarcadastroActionPerformed中的程序中创建Conta时，会将其添加到程序列表中
Conta c = new Conta(...);
program.listaUser.add(c);
// or possibly: program.storeConta(c);
在程序的某个点上，您可能希望显示列表，也许是响应另一个按钮，如果您只是在控制台上打印的话，可能看起来像这样（我不会编写代码）在这里显示在JPanel或其他任何东西中
// other methods that are in class Cadastrar
List<Conta> getContaList()
{
return program.listaUser;
}
void listContas()
{
for (Conta c : program.getContaList()) {
System.out.println(c);
}
}
通常您可以使用this而不是保留单独的变量program
还请注意，我已更改了变量名的大小写……这不是硬性规定，但Java中的约定是，类名应以大写字母开头，例如Conta，而变量名应以小写字母开头，例如{ {1}}，而不是listaUser。
我已经很长时间没有进行Swing编程了，但是（通常曾经是）将 Application 对象与您的主要ListaUser分开，所以您可能会有这种安排...
JFrame