cambiare pannello con un altro

[zipangulu]

Avevo già postato poco tempo fa una domanda simile,ma non avendo ottenuto risposte illuminanti mi trovo a riporre la domanda stavolta in modo più dettagliato sperando di risolvere questo mio maledetto problema...
Ho una JFrame con all'interno dei pannelli e a sua volta altre componenti swing internamente,ecco un'immagine per chiarire un po' la situazione (la stessa immagine l'avevo già postata):

premetto che sto programmando sull'IDE Netbeans,è anche per questo che ritrovo più difficoltà nel gestire questa operazione,e lui per definire,inizializzare e posizionare "jpanel4",utilizza questo frammento di codice (ci troviamo in una classe "Finestra"):

//IGNORATE LE ALTRE COMPONENTI INTERNE
jPanel4 = new javax.swing.JPanel();
jPanel4.setBackground(new java.awt.Color(255, 255, 204)); 
javax.swing.GroupLayout jPanel4Layout = new javax.swing.GroupLayout(jPanel4);
        jPanel4.setLayout(jPanel4Layout);
        jPanel4Layout.setHorizontalGroup(
            jPanel4Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel4Layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(jPanel4Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(jPanel4Layout.createSequentialGroup()
                        .addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                        .addComponent(jComboBox2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(22, 22, 22)
                        .addComponent(jToggleButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 54, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(18, 18, 18)
                        .addComponent(jToggleButton2, javax.swing.GroupLayout.PREFERRED_SIZE, 55, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(14, 14, 14)
                        .addComponent(jToggleButton3, javax.swing.GroupLayout.PREFERRED_SIZE, 57, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(18, 18, 18)
                        .addComponent(jButton8)
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 38, Short.MAX_VALUE))
                    .addComponent(jSeparator2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel4Layout.createSequentialGroup()
                        .addGroup(jPanel4Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING, false)
                            .addComponent(jScrollPane2, javax.swing.GroupLayout.Alignment.LEADING)
                            .addGroup(jPanel4Layout.createSequentialGroup()
                                .addGroup(jPanel4Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                                    .addComponent(jLabel2, javax.swing.GroupLayout.DEFAULT_SIZE, 64, Short.MAX_VALUE)
                                    .addComponent(jLabel1)
                                    .addComponent(jLabel3, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
                                .addGap(18, 18, 18)
                                .addGroup(jPanel4Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                                    .addComponent(jTextField2)
                                    .addComponent(jTextField1, javax.swing.GroupLayout.DEFAULT_SIZE, 438, Short.MAX_VALUE)
                                    .addGroup(jPanel4Layout.createSequentialGroup()
                                        .addComponent(jButton4)
                                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                                        .addComponent(jButton5)
                                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                                        .addComponent(jTextField3, javax.swing.GroupLayout.DEFAULT_SIZE, 324, Short.MAX_VALUE)))))
                        .addGap(89, 89, 89)))
                .addContainerGap())
        );
        jPanel4Layout.setVerticalGroup(
            jPanel4Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel4Layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(jPanel4Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel1)
                    .addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addGroup(jPanel4Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel2, javax.swing.GroupLayout.PREFERRED_SIZE, 18, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(jTextField2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addGroup(jPanel4Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(jPanel4Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                        .addComponent(jLabel3)
                        .addComponent(jTextField3, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addComponent(jButton5))
                    .addComponent(jButton4))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addGroup(jPanel4Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(jComboBox2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(jToggleButton1)
                    .addComponent(jToggleButton2)
                    .addComponent(jToggleButton3)
                    .addComponent(jButton8))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(jSeparator2, javax.swing.GroupLayout.PREFERRED_SIZE, 10, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(jScrollPane2, javax.swing.GroupLayout.PREFERRED_SIZE, 191, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(27, Short.MAX_VALUE))
        );
javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
        jPanel1.setLayout(jPanel1Layout);
        jPanel1Layout.setHorizontalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jPanel2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                    .addComponent(jPanel4, javax.swing.GroupLayout.PREFERRED_SIZE, 541, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(jPanel3, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addContainerGap(20, Short.MAX_VALUE))
        );
        jPanel1Layout.setVerticalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
                .addGap(11, 11, 11)
                .addComponent(jPanel2, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addComponent(jPanel3, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(jPanel4, 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(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        );

        pack();

ora io vorrei aggiungere un Pannello "jPanel5" che sarà un'istanza di una classe esterna,pannello a cui sono state assegnate le stesse dimensioni di "jPanel4" e che dovrei sostituire a quest'ultimo,il codice della classe jPanel5 è qualcosa del genere:

//importazioni varie
public class JPanel5 extends javax.swing.JPanel {
    public JPanel5(/*Message [] msg*/) {  //non fate caso ai parametri passati
        initComponents();       
    }
    private void initComponents() {

        jLabel1 = new javax.swing.JLabel();
        jCheckBox1 = new javax.swing.JCheckBox();
        jScrollPane1 = new javax.swing.JScrollPane();
        jList1 = new javax.swing.JList();

        setBackground(new java.awt.Color(255, 255, 204));
        setPreferredSize(new java.awt.Dimension(619, 345));

        jLabel1.setFont(new java.awt.Font("Tahoma", 1, 12));
        jLabel1.setText("Posta in arrivo");

        jCheckBox1.setBackground(new java.awt.Color(255, 255, 204));
        jCheckBox1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jCheckBox1ActionPerformed(evt);
            }
        });

        jList1.setSelectionBackground(new java.awt.Color(255, 153, 0));
        jScrollPane1.setViewportView(jList1);

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(this);
        this.setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 599, Short.MAX_VALUE)
                    .addComponent(jCheckBox1)
                    .addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 100, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addContainerGap())
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jLabel1)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(jCheckBox1)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 283, Short.MAX_VALUE)
                .addContainerGap())
        );
    }

dunque come dovrei fare per inserire "jPanel5" al posto di jPanel4?

[zipangulu]

Ho risolto!!!
ho fatto semplicemente:

((GroupLayout)jPanel1.getLayout()).replace(jPanel4,new JPanel5());

che credevo di aver già provato con insuccesso ma evidentemente mi sbagliavo

[Andrea1979]

ok, un consiglio però... se puoi, metti via l'editor visuale di qualsivoglia IDE (se non addirittura l'IDE per intero) e impara ad usare i LayoutManager appropriati... ti sarà tutto più chiaro. Tra l'altro SWING e AWT sone le librerie su cui si sono scritti più tutorial in assoluto, quindi è facile reperire un sacco di materiale su componenti e layout.

[zipangulu]

Originariamente inviato da Andrea1979
ok, un consiglio però... se puoi, metti via l'editor visuale di qualsivoglia IDE (se non addirittura l'IDE per intero) e impara ad usare i LayoutManager appropriati... ti sarà tutto più chiaro. Tra l'altro SWING e AWT sone le librerie su cui si sono scritti più tutorial in assoluto, quindi è facile reperire un sacco di materiale su componenti e layout.

Si sono pienamente d'accordo con te,per anni ho "programmato" con il semplice Textpad,gestendo tutto a mano,ma ora sto facendo un client mail che per necessità grafiche mi obbliga all'utilizzo di un IDE,a mano creerei una grafica bruttarella,mentre l'editor visuale di Netbeans mi permette di creare una fantastica grafica,tutto qui,non uso Netbeans come scorciatoia alla riuscita del programma o perchè non conosca i ragionamenti/procedimenti veri e propri da fare riguardo il linguaggio java.
ciao!