Projetei uma GUI usando GridBagLayout e GridBagConstraints. Ele contém um número variável de linhas, cada uma com um dos poucos layouts de coluna possíveis. Para testar o código, compus a GUI de painéis com cores diferentes que ilustram a localização e o comportamento de redimensionamento de todas as células em cada linha e coluna. Essa GUI de teste funciona bem, mas agora preciso automatizar sua construção. Especificamente, preciso que as linhas sejam um dos três tipos diferentes. Se você executar o código abaixo e observar a GUI resultante, poderá ver que a linha1 é um tipo, as linhas 2,6 e 7 são outro tipo e as linhas 3,4 e 5 ainda são um terceiro tipo. Eu preciso que cada um desses três tipos de linhas seja encapsulado em sua própria classe. Além do mais, preciso que meu código seja capaz de criar um número variável de linhas do terceiro tipo (ilustrado pelas linhas 3,4 e 5 no exemplo). (Isso é para software de análise de dados. Os painéis carregam visualizações de dados e ferramentas para manipular as visualizações de dados.)

Quando tento encapsular as linhas em suas próprias classes, a GUI para de parecer como deveria. O código de teste abaixo gera um layout da GUI da maneira que deve parecer. Alguém pode me mostrar como alterar esse código para que ele tenha a funcionalidade descrita no primeiro parágrafo acima?

Você pode colar meu código de teste abaixo no seu IDE para fazê-lo funcionar imediatamente. O código de teste está em dois arquivos separados, da seguinte maneira:

O código para GridBagLayoutDemo.java é:

import java.awt.*;
import javax.swing.JFrame;

public class GridBagLayoutDemo {
    final static boolean RIGHT_TO_LEFT = false;

    public static void addComponentsToPane(Container pane) {
        if (RIGHT_TO_LEFT) {pane.setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);}
        pane.setLayout(new GridBagLayout());

// top row (fill, gridx, gridy, gridwidth 1, weightx 0, weighty 0, ipady 0)
        TestPanel panelr1c1 = new TestPanel(Color.black);
        GridBagConstraints constraint_r1c1 = getGridBagConstraints(GridBagConstraints.NONE,0,0,1,0,0,0);
        pane.add(panelr1c1,constraint_r1c1);

        TestPanel panelr1c2 = new TestPanel(Color.blue);
        GridBagConstraints constraint_r1c2 = getGridBagConstraints(GridBagConstraints.HORIZONTAL,1,0,1,0.8,0,0);
        pane.add(panelr1c2,constraint_r1c2);

        TestPanel panelr1c2a = new TestPanel(Color.green);
        GridBagConstraints constraint_r1c2a = getGridBagConstraints(GridBagConstraints.HORIZONTAL,2,0,1,0.8,0,0);
        pane.add(panelr1c2a,constraint_r1c2a);

        TestPanel panelr1c3 = new TestPanel(Color.red);
        GridBagConstraints constraint_r1c3 = getGridBagConstraints(GridBagConstraints.NONE,3,0,1,0,0,0);
        pane.add(panelr1c3,constraint_r1c3);

        TestPanel panelr1c4 = new TestPanel(Color.blue);
        GridBagConstraints constraint_r1c4 = getGridBagConstraints(GridBagConstraints.NONE,4,0,1,0,0,0);
        pane.add(panelr1c4,constraint_r1c4);

// second row (fill, gridx, gridy, gridwidth 1, weightx 0, weighty 0, ipady 0)
        TestPanel panelr2c1 = new TestPanel(Color.magenta);
        GridBagConstraints constraint_r2c1 = getGridBagConstraints(GridBagConstraints.NONE,0,1,1,0,0,0);
        pane.add(panelr2c1,constraint_r2c1);

        TestPanel panelr2c2 = new TestPanel(Color.pink);
        GridBagConstraints constraint_r2c2 = getGridBagConstraints(GridBagConstraints.HORIZONTAL,1,1,2,1.0,0,0);
        pane.add(panelr2c2,constraint_r2c2);

        TestPanel panelr2c3 = new TestPanel(Color.black);
        GridBagConstraints constraint_r2c3 = getGridBagConstraints(GridBagConstraints.NONE,3,1,1,0,0,0);
        pane.add(panelr2c3,constraint_r2c3);

        TestPanel panelr2c4 = new TestPanel(Color.pink);
        GridBagConstraints constraint_r2c4 = getGridBagConstraints(GridBagConstraints.NONE,4,1,1,0,0,0);
        pane.add(panelr2c4,constraint_r2c4);

// third row (fill, gridx, gridy, gridwidth 1, weightx 0, weighty 0, ipady 0)
        TestPanel panelr3c1 = new TestPanel(Color.gray);
        GridBagConstraints constraint_r3c1 = getGridBagConstraints(GridBagConstraints.VERTICAL,0,2,1,0,0.5,40);
        pane.add(panelr3c1,constraint_r3c1);

        TestPanel panelr3c2 = new TestPanel(Color.orange);
        GridBagConstraints constraint_r3c2 = getGridBagConstraints(GridBagConstraints.BOTH,1,2,2,1.0,0.5,40);
        pane.add(panelr3c2,constraint_r3c2);

        TestPanel panelr3c3 = new TestPanel(Color.red);
        GridBagConstraints constraint_r3c3 = getGridBagConstraints(GridBagConstraints.VERTICAL,3,2,1,0,0.5,40);
        pane.add(panelr3c3,constraint_r3c3);

        TestPanel panelr3c4 = new TestPanel(Color.orange);
        GridBagConstraints constraint_r3c4 = getGridBagConstraints(GridBagConstraints.VERTICAL,4,2,1,0,0.5,40);
        pane.add(panelr3c4,constraint_r3c4);

// fourth row (fill, gridx, gridy, gridwidth 1, weightx 0, weighty 0, ipady 0)
        TestPanel panelr4c1 = new TestPanel(Color.black);
        GridBagConstraints constraint_r4c1 = getGridBagConstraints(GridBagConstraints.VERTICAL,0,3,1,0,0.5,40);
        pane.add(panelr4c1,constraint_r4c1);

        TestPanel panelr4c2 = new TestPanel(Color.white);
        GridBagConstraints constraint_r4c2 = getGridBagConstraints(GridBagConstraints.BOTH,1,3,2,1.0,0.5,40);
        pane.add(panelr4c2,constraint_r4c2);

        TestPanel panelr4c3 = new TestPanel(Color.green);
        GridBagConstraints constraint_r4c3 = getGridBagConstraints(GridBagConstraints.VERTICAL,3,3,1,0,0.5,40);
        pane.add(panelr4c3,constraint_r4c3);

        TestPanel panelr4c4 = new TestPanel(Color.blue);
        GridBagConstraints constraint_r4c4 = getGridBagConstraints(GridBagConstraints.VERTICAL,4,3,1,0,0.5,40);
        pane.add(panelr4c4,constraint_r4c4);

// fifth row (fill, gridx, gridy, gridwidth 1, weightx 0, weighty 0, ipady 0)
        TestPanel panelr5c1 = new TestPanel(Color.darkGray);
        GridBagConstraints constraint_r5c1 = getGridBagConstraints(GridBagConstraints.VERTICAL,0,4,1,0,0.5,40);
        pane.add(panelr5c1,constraint_r5c1);

        TestPanel panelr5c2 = new TestPanel(Color.yellow);
        GridBagConstraints constraint_r5c2 = getGridBagConstraints(GridBagConstraints.BOTH,1,4,2,1.0,0.5,40);
        pane.add(panelr5c2,constraint_r5c2);

        TestPanel panelr5c3 = new TestPanel(Color.white);
        GridBagConstraints constraint_r5c3 = getGridBagConstraints(GridBagConstraints.VERTICAL,3,4,1,0,0.5,40);
        pane.add(panelr5c3,constraint_r5c3);

        TestPanel panelr5c4 = new TestPanel(Color.orange);
        GridBagConstraints constraint_r5c4 = getGridBagConstraints(GridBagConstraints.VERTICAL,4,4,1,0,0.5,40);
        pane.add(panelr5c4,constraint_r5c4);

// sixth row (fill, gridx, gridy, gridwidth 1, weightx 0, weighty 0, ipady 0)
        TestPanel panelr6c1 = new TestPanel(Color.green);
        GridBagConstraints constraint_r6c1 = getGridBagConstraints(GridBagConstraints.NONE,0,5,1,0,0,0);
        pane.add(panelr6c1,constraint_r6c1);

        TestPanel panelr6c2 = new TestPanel(Color.blue);
        GridBagConstraints constraint_r6c2 = getGridBagConstraints(GridBagConstraints.HORIZONTAL,1,5,2,1.0,0,0);
        pane.add(panelr6c2,constraint_r6c2);

        TestPanel panelr6c3 = new TestPanel(Color.red);
        GridBagConstraints constraint_r6c3 = getGridBagConstraints(GridBagConstraints.NONE,3,5,1,0,0,0);
        pane.add(panelr6c3,constraint_r6c3);

        TestPanel panelr6c4 = new TestPanel(Color.black);
        GridBagConstraints constraint_r6c4 = getGridBagConstraints(GridBagConstraints.NONE,4,5,1,0,0,0);
        pane.add(panelr6c4,constraint_r6c4);

// seventh row (fill, gridx, gridy, gridwidth 1, weightx 0, weighty 0, ipady 0)
        TestPanel panelr7c1 = new TestPanel(Color.darkGray);
        GridBagConstraints constraint_r7c1 = getGridBagConstraints(GridBagConstraints.NONE,0,6,1,0,0,0);
        pane.add(panelr7c1,constraint_r7c1);

        TestPanel panelr7c2 = new TestPanel(Color.white);
        GridBagConstraints constraint_r7c2 = getGridBagConstraints(GridBagConstraints.HORIZONTAL,1,6,2,1.0,0,0);
        pane.add(panelr7c2,constraint_r7c2);

        TestPanel panelr7c3 = new TestPanel(Color.yellow);
        GridBagConstraints constraint_r7c3 = getGridBagConstraints(GridBagConstraints.NONE,3,6,1,0,0,0);
        pane.add(panelr7c3,constraint_r7c3);

        TestPanel panelr7c4 = new TestPanel(Color.green);
        GridBagConstraints constraint_r7c4 = getGridBagConstraints(GridBagConstraints.NONE,4,6,1,0,0,0);
        pane.add(panelr7c4,constraint_r7c4);
    }

    // Create the GUI and show it.  For thread safety, this method should be invoked from the event-dispatching thread.
    private static void createAndShowGUI() {
        //Create and set up the window.
        JFrame frame = new JFrame("GridBagConstraint Practice");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        //Set up the content pane.
        addComponentsToPane(frame.getContentPane());
        //Display the window.
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        //Schedule a job for the event-dispatching thread: creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() {public void run() {createAndShowGUI();}});
    }
    private static GridBagConstraints getGridBagConstraints(int fill, int gridx, int gridy, int gridwidth, double weightx, double weighty, int ipady){
        GridBagConstraints myGridBagConstraints = new GridBagConstraints();
          myGridBagConstraints.fill=fill;
        myGridBagConstraints.gridx=gridx;
        myGridBagConstraints.gridy=gridy;
        myGridBagConstraints.gridwidth=gridwidth;
        myGridBagConstraints.weightx=weightx;
        myGridBagConstraints.weighty=weighty;
        myGridBagConstraints.ipady=ipady;
        return myGridBagConstraints;
    }
}

O código do TestPanel.java é:

import java.awt.Color;
import javax.swing.JPanel;

public class TestPanel extends JPanel {
    public TestPanel (Color myColor){this.setBackground(myColor);}
}