org.eclipse.swt.custom.StackLayout.java Source code

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Here is the source code for org.eclipse.swt.custom.StackLayout.java

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/*******************************************************************************
 * Copyright (c) 2000, 2006 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 ******************************************************************************/
package org.eclipse.swt.custom;

// import org.eclipse.swt.*;
// import org.eclipse.swt.graphics.*;
// import org.eclipse.rap.widgets.*;
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Layout;

/**
 * This Layout stacks all the controls one on top of the other and resizes all
 * controls to have the same size and location. The control specified in
 * topControl is visible and all other controls are not visible. Users must set
 * the topControl value to flip between the visible items and then call layout()
 * on the composite which has the StackLayout.
 * <p>
 * Here is an example which places ten buttons in a stack layout and flips
 * between them:
 * 
 * <pre><code>
 * public static void main( String[] args ) {
 *   Display display = new Display();
 *   Shell shell = new Shell( display );
 *   shell.setLayout( new GridLayout() );
 *   final Composite parent = new Composite( shell, SWT.NONE );
 *   parent.setLayoutData( new GridData( GridData.FILL_BOTH ) );
 *   final StackLayout layout = new StackLayout();
 *   parent.setLayout( layout );
 *   final Button[] bArray = new Button[ 10 ];
 *   for( int i = 0; i &lt; 10; i++ ) {
 *     bArray[ i ] = new Button( parent, SWT.PUSH );
 *     bArray[ i ].setText( &quot;Button &quot; + i );
 *   }
 *   layout.topControl = bArray[ 0 ];
 *   Button b = new Button( shell, SWT.PUSH );
 *   b.setText( &quot;Show Next Button&quot; );
 *   final int[] index = new int[ 1 ];
 *   b.addListener( SWT.Selection, new Listener() {
 * 
 *     public void handleEvent( Event e ) {
 *       index[ 0 ] = ( index[ 0 ] + 1 ) % 10;
 *       layout.topControl = bArray[ index[ 0 ] ];
 *       parent.layout();
 *     }
 *   } );
 *   shell.open();
 *   while( shell != null &amp;&amp; !shell.isDisposed() ) {
 *     if( !display.readAndDispatch() )
 *       display.sleep();
 *   }
 * }
 * </code></pre>
 */
public class StackLayout extends Layout {
    /**
     * marginWidth specifies the number of pixels of horizontal margin that will
     * be placed along the left and right edges of the layout. The default value
     * is 0.
     */
    public int marginWidth = 0;
    /**
     * marginHeight specifies the number of pixels of vertical margin that will be
     * placed along the top and bottom edges of the layout. The default value is
     * 0.
     */
    public int marginHeight = 0;
    /**
     * topControl the Control that is displayed at the top of the stack. All other
     * controls that are children of the parent composite will not be visible.
     */
    public Control topControl;

    protected Point computeSize(Composite composite, int wHint, int hHint, boolean flushCache) {
        Control children[] = composite.getChildren();
        int maxWidth = 0;
        int maxHeight = 0;
        for (int i = 0; i < children.length; i++) {
            Point size = children[i].computeSize(wHint, hHint, flushCache);
            maxWidth = Math.max(size.x, maxWidth);
            maxHeight = Math.max(size.y, maxHeight);
        }
        int width = maxWidth + 2 * marginWidth;
        int height = maxHeight + 2 * marginHeight;
        if (wHint != SWT.DEFAULT)
            width = wHint;
        if (hHint != SWT.DEFAULT)
            height = hHint;
        return new Point(width, height);
    }

    protected boolean flushCache(Control control) {
        return true;
    }

    protected void layout(Composite composite, boolean flushCache) {
        Control children[] = composite.getChildren();
        Rectangle rect = composite.getClientArea();
        rect.x += marginWidth;
        rect.y += marginHeight;
        rect.width -= 2 * marginWidth;
        rect.height -= 2 * marginHeight;
        for (int i = 0; i < children.length; i++) {
            children[i].setBounds(rect);
            children[i].setVisible(children[i] == topControl);
        }
    }

    String getName() {
        String string = getClass().getName();
        int index = string.lastIndexOf('.');
        if (index == -1)
            return string;
        return string.substring(index + 1, string.length());
    }

    /**
     * Returns a string containing a concise, human-readable description of the
     * receiver.
     * 
     * @return a string representation of the layout
     */
    public String toString() {
        String string = getName() + " {";
        if (marginWidth != 0)
            string += "marginWidth=" + marginWidth + " ";
        if (marginHeight != 0)
            string += "marginHeight=" + marginHeight + " ";
        if (topControl != null)
            string += "topControl=" + topControl + " ";
        string = string.trim();
        string += "}";
        return string;
    }
}