Instances of this class control the position and size of the children of a composite control by using <code>FormAttachments</code> to optionally configure the left, top, right and bottom edges of each child. <p> The following example code creates a <code>FormLayout</code> and then sets it into a <code>Shell</code>: <pre> Display display = new Display (); Shell shell = new Shell(display); FormLayout layout = new FormLayout(); layout.marginWidth = 3; layout.marginHeight = 3; shell.setLayout(layout); </pre> </p> <p> To use a <code>FormLayout</code>, create a <code>FormData</code> with <code>FormAttachment</code> for each child of <code>Composite</code>. The following example code attaches <code>button1</code> to the top and left edge of the composite and <code>button2</code> to the right edge of <code>button1</code> and the top and right edges of the composite: <pre> FormData data1 = new FormData(); data1.left = new FormAttachment(0, 0); data1.top = new FormAttachment(0, 0); button1.setLayoutData(data1); FormData data2 = new FormData(); data2.left = new FormAttachment(button1); data2.top = new FormAttachment(0, 0); data2.right = new FormAttachment(100, 0); button2.setLayoutData(data2); </pre> </p> <p> Each side of a child control can be attached to a position in the parent composite, or to other controls within the <code>Composite</code> by creating instances of <code>FormAttachment</code> and setting them into the top, bottom, left, and right fields of the child's <code>FormData</code>. </p> <p> If a side is not given an attachment, it is defined as not being attached to anything, causing the child to remain at its preferred size. If a child is given no attachment on either the left or the right or top or bottom, it is automatically attached to the left and top of the composite respectively. The following code positions <code>button1</code> and <code>button2</code> but relies on default attachments: <pre> FormData data2 = new FormData(); data2.left = new FormAttachment(button1); data2.right = new FormAttachment(100, 0); button2.setLayoutData(data2); </pre> </p> <p> IMPORTANT: Do not define circular attachments. For example, do not attach the right edge of <code>button1</code> to the left edge of <code>button2</code> and then attach the left edge of <code>button2</code> to the right edge of <code>button1</code>. This will over constrain the layout, causing undefined behavior. The algorithm will terminate, but the results are undefined. </p>
Copyright (c) 2000, 2008 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 Port to the D programming language: Frank Benoit <benoit@tionex.de>