Swing component setSize()/setBounds() issue

Overview
Example Code
Screenshots of Problem

1. Overview of problem

So I'm writing a GUI for a complicated program I'm developing, and I get tired of trying to get components to scale correctly when the window is resized.

At first I was using several layouts inside the jframe, and each jpanel to try and place the components correctly and scale them appropriately. Naturally, I got fed up with them, and I started trying to scale and set the x,y positions of the components dynamically (it's so much easier :D).

Basically I'm trying to divide the screen into three sections left margin (JSplitPane), center (JTabbedPane), and right margin (JSplitPane). I don't think the internal components matter at this point. The main problem is the right JSplitPane scales over the whole window despite my using setBounds() to place the x,y over on the right and set the size to 21% of the total width. It seems to interact weird with the other panels.

2. Example Code

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JSplitPane;
import javax.swing.JTabbedPane;

import java.awt.event.ComponentEvent;
import java.awt.event.ComponentListener;
import java.awt.event.WindowEvent;
import java.awt.event.WindowListener;
import java.awt.Dimension;

@SuppressWarnings("deprecation")
public class test extends JFrame implements WindowListener {

/* Constants =========================================================================*/
    private         final   double      LEFT_SIZE           =   .21;
    private         final   double      CENTER_SIZE         =   .58;
    private         final   double      RIGHT_SIZE          =   .21;
    private         final   int         TOP_PADDING         =   50;
    private         final   int         LEFT_PADDING        =   4;
    private         final   int         RIGHT_PADDING       =   4;
    private         final   int         BOTTOM_PADDING      =   4;
    private         final   int         MIN_WIDTH           =   640;
    private         final   int         MIN_HEIGHT          =   480;

    public  static  final   String      INIT_TITLE          =   "TestFrame v0.01";
/* End Constants =====================================================================*/

/* Instance Variables ================================================================*/
    private                 int         contentWidth;
    private                 int         contentHeight;
/* End Instance Variables ============================================================*/

/* Objects ===========================================================================*/        
    public  static  test        window;     

    /* Begin Frame Design =========================================================== */
        private         JSplitPane      left;
        private         JButton           button1;  private     JButton     button2;            
        private         JTabbedPane     center;
        private         JPanel            panel1;       private     JPanel      panel2;         
        private         JSplitPane      right;
        private         JButton           button3;  private     JButton     button4;
    /* End Frame Design ============================================================= */

/* End Objects ====================================================================== */

/** Initializes and Places all GUI elements **/
public test ( String windowName ) {
    super(windowName);              //call parent constructor
    this.addWindowListener(this);   //adds window event functionality such as close

    this.setExtendedState(this.getExtendedState() | JFrame.MAXIMIZED_BOTH); //Starts program maximized
    this.setMinimumSize(new Dimension(MIN_WIDTH,MIN_HEIGHT));
    this.setVisible(true);
    this.setMaximumSize(this.getSize());        

    /* Begin Init JFrame this ------------------------------------------------------------ */       
            button1 = new JButton("button1");               
            button2 = new JButton("button2");               
        left = new JSplitPane(JSplitPane.VERTICAL_SPLIT, button1, button2);
        left.setResizeWeight(1);

            button3 = new JButton("button3");               
            button4 = new JButton("button4");               
        right = new JSplitPane(JSplitPane.VERTICAL_SPLIT, button3, button4);
        right.setResizeWeight(.25);

            panel1 = new JPanel();              
            panel2 = new JPanel();              
        center = new JTabbedPane();
        center.addTab("Panel1", panel1);
        center.addTab("Panel2", panel2);

        this.add(left);
        this.add(center);
        this.add(right);

        this.addComponentListener(new ComponentListener() {
            @Override
            public void componentResized    (ComponentEvent e) {
                window.contentWidth = window.getWidth() - window.LEFT_PADDING - window.RIGHT_PADDING;
                window.contentHeight = window.getHeight() - window.TOP_PADDING - window.BOTTOM_PADDING;

                window.left.setBounds               (   0,                                                  0,  (int)(window.contentWidth * window.LEFT_SIZE),      window.contentHeight);
                window.center.setBounds             (   window.left.getWidth(),                             0,  (int)(window.contentWidth * window.CENTER_SIZE),    window.contentHeight);
                window.panel1.setBounds             (   0,                                                  0,  (int)(window.contentWidth * window.CENTER_SIZE),    window.contentHeight);
                window.panel2.setBounds             (   0,                                                  0,  (int)(window.contentWidth * window.CENTER_SIZE),    window.contentHeight);
                window.right.setBounds              (   window.left.getWidth() + window.center.getWidth(),  0,  (int)(window.contentWidth * window.RIGHT_SIZE),     window.contentHeight);
             }
            public void componentHidden     (ComponentEvent e) {}
            public void componentMoved      (ComponentEvent e) {}
            public void componentShown      (ComponentEvent e) {}    

        });
        /* End Init JFrame this -------------------------------------------------------------- */
}

// window event abstracts
@Override
public void windowClosing       (WindowEvent event)     { window.dispose(); System.exit(0); } 
public void windowClosed        (WindowEvent event)     {}
public void windowDeiconified   (WindowEvent event)     {} 
public void windowIconified     (WindowEvent event)     {} 
public void windowActivated     (WindowEvent event)     {} 
public void windowDeactivated   (WindowEvent event)     {} 
public void windowOpened        (WindowEvent event)     {}

public static void main(String[] args){     
    window = new test(INIT_TITLE); 
    window.setVisible(true);
}
}

3. Screenshots

trashgod

I don't think the internal components matter at this point.

As discussed in Should I avoid the use of set[Preferred|Maximum|Minimum]Size methods in Java Swing?, nothing could be further from the truth. Correct use of layouts relies on a component's preferred size. That size is carefully calculated based on the contents. Second guessing, as shown in your example, is doomed to fail.

Instead, add components and pack() the frame. In the example below, the center panel returns an arbitrary result to show how pack() does its work.

Addendum: Two additional points helpfully adduced by @mKorbel:

Swing GUI objects should be constructed and manipulated only on the event dispatch thread.
See also this example that shows how to use setDividerLocation() in invokeLater().

import java.awt.BorderLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JSplitPane;
import javax.swing.JTabbedPane;
import java.awt.Dimension;
import java.awt.EventQueue;

public class Test extends JFrame {

    public static final String INIT_TITLE = "TestFrame v0.02";
    public static Test window;
    private JSplitPane left;
    private JTabbedPane center;
    private JSplitPane right;

    public Test(String windowName) {
        super(windowName);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        left = new JSplitPane(JSplitPane.VERTICAL_SPLIT,
            new JButton("button1"), new JButton("button2"));
        left.setResizeWeight(0.5);

        right = new JSplitPane(JSplitPane.VERTICAL_SPLIT,
            new JButton("button3"), new JButton("button4"));
        right.setResizeWeight(0.5);

        center = new JTabbedPane();
        center.addTab("Panel1", new MyPanel());
        center.addTab("Panel2", new MyPanel());

        this.add(left, BorderLayout.WEST);
        this.add(center, BorderLayout.CENTER);
        this.add(right, BorderLayout.EAST);

        this.pack();
        this.setLocationByPlatform(true);
        this.setVisible(true);
    }

    private static class MyPanel extends JPanel {

        private Dimension d = new Dimension(320, 240);

        @Override
        public Dimension getPreferredSize() {
            return d;
        }
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                window = new Test(INIT_TITLE);
                window.setVisible(true);
            }
        });
    }
}

来源：https://stackoverflow.com/questions/9117458/swing-component-setsize-setbounds-issue

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