Java LayoutManager .preferredLayoutSize (Container parent)

Dimension preferredLayoutSize(Container parent)

//from w w  w.ja  v a  2 s. co  m


/*
 *
 * Copyright (c) 1998 Sun Microsystems, Inc. All Rights Reserved.
 *
 * Sun grants you ("Licensee") a non-exclusive, royalty free, license to use,
 * modify and redistribute this software in source and binary code form,
 * provided that i) this copyright notice and license appear on all copies of
 * the software; and ii) Licensee does not utilize the software in a manner
 * which is disparaging to Sun.
 *
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING ANY
 * IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR
 * NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE
 * LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING
 * OR DISTRIBUTING THE SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS
 * LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT,
 * INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER
 * CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF
 * OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGES.
 *
 * This software is not designed or intended for use in on-line control of
 * aircraft, air traffic, aircraft navigation or aircraft communications; or in
 * the design, construction, operation or maintenance of any nuclear
 * facility. Licensee represents and warrants that it will not use or
 * redistribute the Software for such purposes.
 */

import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Insets;
import java.awt.LayoutManager;

import javax.swing.JButton;
import javax.swing.JFrame;

public class Main {
    public static void addComponentsToPane(Container pane) {
        pane.setLayout(new DiagonalLayout());

        pane.add(new JButton("Button 1"));
        pane.add(new JButton("Button 2"));
        pane.add(new JButton("Button 3"));
        pane.add(new JButton("Button 4"));
        pane.add(new JButton("Button 5"));
    }

    /**
     * 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("CustomLayoutDemo");
        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();
            }
        });
    }
}


/*
 * 1.2+ version.  Used by CustomLayoutDemo.java.
 */

class DiagonalLayout implements LayoutManager {
    private int vgap;
    private int minWidth = 0, minHeight = 0;
    private int preferredWidth = 0, preferredHeight = 0;
    private boolean sizeUnknown = true;

    public DiagonalLayout() {
        this(5);
    }

    public DiagonalLayout(int v) {
        vgap = v;
    }

    /* Required by LayoutManager. */
    public void addLayoutComponent(String name, Component comp) {
    }

    /* Required by LayoutManager. */
    public void removeLayoutComponent(Component comp) {
    }

    private void setSizes(Container parent) {
        int nComps = parent.getComponentCount();
        Dimension d = null;

        //Reset preferred/minimum width and height.
        preferredWidth = 0;
        preferredHeight = 0;
        minWidth = 0;
        minHeight = 0;

        for (int i = 0; i < nComps; i++) {
            Component c = parent.getComponent(i);
            if (c.isVisible()) {
                d = c.getPreferredSize();

                if (i > 0) {
                    preferredWidth += d.width/2;
                    preferredHeight += vgap;
                } else {
                    preferredWidth = d.width;
                }
                preferredHeight += d.height;

                minWidth = Math.max(c.getMinimumSize().width,
                                    minWidth);
                minHeight = preferredHeight;
            }
        }
    }


    /* Required by LayoutManager. */
    public Dimension preferredLayoutSize(Container parent) {
        Dimension dim = new Dimension(0, 0);
        int nComps = parent.getComponentCount();

        setSizes(parent);

        //Always add the container's insets!
        Insets insets = parent.getInsets();
        dim.width = preferredWidth
                    + insets.left + insets.right;
        dim.height = preferredHeight
                     + insets.top + insets.bottom;

        sizeUnknown = false;

        return dim;
    }

    /* Required by LayoutManager. */
    public Dimension minimumLayoutSize(Container parent) {
        Dimension dim = new Dimension(0, 0);
        int nComps = parent.getComponentCount();

        //Always add the container's insets!
        Insets insets = parent.getInsets();
        dim.width = minWidth
                    + insets.left + insets.right;
        dim.height = minHeight
                     + insets.top + insets.bottom;

        sizeUnknown = false;

        return dim;
    }

    /* Required by LayoutManager. */
    /*
     * This is called when the panel is first displayed,
     * and every time its size changes.
     * Note: You CAN'T assume preferredLayoutSize or
     * minimumLayoutSize will be called -- in the case
     * of applets, at least, they probably won't be.
     */
    public void layoutContainer(Container parent) {
        Insets insets = parent.getInsets();
        int maxWidth = parent.getWidth()
                       - (insets.left + insets.right);
        int maxHeight = parent.getHeight()
                        - (insets.top + insets.bottom);
        int nComps = parent.getComponentCount();
        int previousWidth = 0, previousHeight = 0;
        int x = 0, y = insets.top;
        int rowh = 0, start = 0;
        int xFudge = 0, yFudge = 0;
        boolean oneColumn = false;

        // Go through the components' sizes, if neither
        // preferredLayoutSize nor minimumLayoutSize has
        // been called.
        if (sizeUnknown) {
            setSizes(parent);
        }

        if (maxWidth <= minWidth) {
            oneColumn = true;
        }

        if (maxWidth != preferredWidth) {
            xFudge = (maxWidth - preferredWidth)/(nComps - 1);
        }

        if (maxHeight > preferredHeight) {
            yFudge = (maxHeight - preferredHeight)/(nComps - 1);
        }

        for (int i = 0 ; i < nComps ; i++) {
            Component c = parent.getComponent(i);
            if (c.isVisible()) {
                Dimension d = c.getPreferredSize();

                 // increase x and y, if appropriate
                if (i > 0) {
                    if (!oneColumn) {
                        x += previousWidth/2 + xFudge;
                    }
                    y += previousHeight + vgap + yFudge;
                }

                // If x is too large,
                if ((!oneColumn) &&
                    (x + d.width) >
                    (parent.getWidth() - insets.right)) {
                    // reduce x to a reasonable number.
                    x = parent.getWidth()
                        - insets.bottom - d.width;
                }

                // If y is too large,
                if ((y + d.height)
                    > (parent.getHeight() - insets.bottom)) {
                    // do nothing.
                    // Another choice would be to do what we do to x.
                }

                // Set the component's size and position.
                c.setBounds(x, y, d.width, d.height);

                previousWidth = d.width;
                previousHeight = d.height;
            }
        }
    }

    public String toString() {
        String str = "";
        return getClass().getName() + "[vgap=" + vgap + str + "]";
    }
}