Java swing layout

Question

Im having a hard time identifying what layout to be used. help any suggestions.

JPanel mainpanel = new JPanel();

public void addPanel(JPanel panel){
    mainpanel.add(panel);
}

addPanel(A);
addPanel(B);
addPanel(C);
addPanel(D);
addPanel(E);
....

Panels A,B,C,D... are not of fixed sized.

How can I make this possible?

Answer 1

Seems like by using GridBagLayout, you can achieve this. Hopefully you can change the JPanel with MAGENTA colour as per your liking :-)

Here is the output :

And here is the code :

 import java.awt.*;
 import javax.swing.*; //swing package

 public class GridBagLayoutTest
 {


    //defining the constructor
    public GridBagLayoutTest() 
    {

        JFrame maFrame = new JFrame("The main screen"); //creating main Jframe
        maFrame.setLocationByPlatform(true); //centering frame

        JPanel headPanel = new JPanel(); //creating the header panel

        Container container = maFrame.getContentPane();
        container.setLayout(new GridBagLayout()); //setting layout of main frame
        GridBagConstraints cns = new GridBagConstraints(); //creating constraint
        cns.gridx = 0;
        cns.gridy = 0;
        //cns.gridwidth = 3;
        //cns.gridheight = 4;
        cns.weightx = 0.5;
        cns.weighty = 0.2;
        cns.anchor = GridBagConstraints.FIRST_LINE_START;
        cns.fill = GridBagConstraints.BOTH;        
        headPanel.setBackground(Color.BLUE);
        container.add(headPanel, cns);

        JPanel panel = new JPanel();
        panel.setBackground(Color.CYAN);
        cns = new GridBagConstraints();
        cns.gridx = 1;
        cns.gridy = 0;
        //cns.gridwidth = 7;
        //cns.gridheight = 4;
        cns.weightx = 0.5;
        cns.weighty = 0.2;
        cns.anchor = GridBagConstraints.FIRST_LINE_END;
        cns.fill = GridBagConstraints.BOTH;
        container.add(panel, cns);

        JPanel panel1 = new JPanel();
        panel1.setBackground(Color.RED);
        cns = new GridBagConstraints();
        cns.gridx = 0;
        cns.gridy = 1;
        //cns.gridwidth = 2;
        cns.gridheight = 2;
        cns.weightx = 0.5;
        cns.weighty = 0.3;
        cns.anchor = GridBagConstraints.LINE_START;
        cns.fill = GridBagConstraints.BOTH;
        container.add(panel1, cns);     

        JPanel panel2 = new JPanel();
        panel2.setBackground(Color.PINK);
        cns = new GridBagConstraints();
        cns.gridx = 1;
        cns.gridy = 1;
        //cns.gridwidth = 2;
        //cns.gridheight = 2;
        cns.weightx = 0.5;
        cns.weighty = 0.2;
        cns.anchor = GridBagConstraints.LINE_END;
        cns.fill = GridBagConstraints.BOTH;
        container.add(panel2, cns);                 

        JPanel panel4 = new JPanel();
        panel4.setBackground(Color.ORANGE);
        cns = new GridBagConstraints();
        cns.gridx = 1;
        cns.gridy = 2;
        //cns.gridwidth = 2;
        //cns.gridheight = 2;
        cns.weightx = 0.5;
        cns.weighty = 0.2;
        cns.anchor = GridBagConstraints.LINE_END;
        cns.fill = GridBagConstraints.BOTH;
        container.add(panel4, cns); 

        JPanel mainPanel = new JPanel();
        mainPanel.setBackground(Color.WHITE);
        mainPanel.setLayout(new GridBagLayout());
        cns = new GridBagConstraints();
        cns.gridx = 0;
        cns.gridy = 4;
        cns.gridwidth = 2;
        cns.gridheight = 2;
        cns.weightx = 1.0;
        cns.weighty = 0.3;
        cns.anchor = GridBagConstraints.LAST_LINE_START;
        cns.fill = GridBagConstraints.BOTH;
        container.add(mainPanel, cns); 

        JPanel panel3 = new JPanel();
        panel3.setBackground(Color.MAGENTA);
        cns = new GridBagConstraints();
        cns.gridx = 0;
        cns.gridy = 0;
        //cns.gridwidth = 2;
        //cns.gridheight = 2;
        cns.weightx = 0.5;
        cns.weighty = 0.2;
        cns.anchor = GridBagConstraints.FIRST_LINE_START;
        cns.fill = GridBagConstraints.BOTH;
        mainPanel.add(panel3, cns); 

        JPanel bottomPanel = new JPanel();
        bottomPanel.setBackground(Color.WHITE);
        cns = new GridBagConstraints();
        cns.gridx = 0;
        cns.gridy = 1;
        //cns.gridwidth = 2;
        //cns.gridheight = 2;
        cns.weightx = 1.0;
        cns.weighty = 0.2;
        cns.anchor = GridBagConstraints.LAST_LINE_START;
        cns.fill = GridBagConstraints.BOTH;
        mainPanel.add(bottomPanel, cns); 

        //JButton button = new JButton("BUTTON");
        //headPanel.add(button);

        maFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //setting the default close operation of JFrame
        maFrame.pack();
        maFrame.setVisible(true); //making the frame visible
    }

    //defining the main method
    public static void main(String[] args) 
    {
        Runnable runnable = new Runnable()
        {
            public void run()
            {
                new GridBagLayoutTest(); //instantiating the class
            }
        };
        SwingUtilities.invokeLater(runnable);       
    }
}

Answer 2

Consider using JGoodies Forms layout. it is highly flexible and easy to use. Any sort of layouting of widgets are possible, vertical stacking , horizontal stacking etc.

http://www.jgoodies.com/freeware/forms/index.html

                   /* B1   Space  B2    Space B3    Space  B4 */
     String col1 = "10dlu, 3dlu, 10dlu, 3dlu 10dlu, 3dlu, 10ldu";
                   /*Width of button */ 
     String row1 = "5dlu";

     FormLayout layout = new FormLayout( col1, row1);

     JPanel panel = new JPanel(layout); 

     panel.setBorder(Borders.DIALOG_BORDER);

     CellConstraints cc = new CellConstraints();

     /* X - stands for column position :: Y - stand for row */  
     panel.add(new JButton("B1"), cc.xy(1, 1));

     panel.add(new JButton("B2"), cc.xy(2, 1));
     .
     .
     . 
     there is one more cc.xyh(1,1,2) where 'h' stands for vertical span or width.   

Yes, you read more about JGoodies forms layout, 'DLU' means dialog units, rather than me explaining all these, kindly visit JGoodies site, download the library and documentation. Trust be, this layout manager is much better, in terms of usability , maintainability and readability.