LayoutManager.preferredLayoutSize(Container parent) has the following syntax.
Dimension preferredLayoutSize(Container parent)
In the following code shows how to use LayoutManager.preferredLayoutSize(Container parent) method.
//from w w w. j a va 2s .com /* * * 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 + "]"; } }