Java tutorial
/******************************************************************************* * Copyright (c) 2002, 2015 Innoopract Informationssysteme GmbH 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: * Innoopract Informationssysteme GmbH - initial API and implementation * EclipseSource - ongoing development ******************************************************************************/ package org.eclipse.swt.widgets; import org.eclipse.rap.rwt.internal.lifecycle.WidgetLCA; import org.eclipse.rap.rwt.internal.textsize.TextSizeUtil; import org.eclipse.rap.rwt.internal.theme.ThemeAdapter; import org.eclipse.rap.rwt.theme.BoxDimensions; import org.eclipse.swt.SWT; import org.eclipse.swt.SWTException; import org.eclipse.swt.graphics.Font; import org.eclipse.swt.graphics.Point; import org.eclipse.swt.graphics.Rectangle; import org.eclipse.swt.internal.widgets.groupkit.GroupLCA; import org.eclipse.swt.internal.widgets.groupkit.GroupThemeAdapter; /** * Instances of this class provide an etched border * with an optional title. * <p> * Shadow styles are hints and may not be honoured * by the platform. To create a group with the * default shadow style for the platform, do not * specify a shadow style.</p> * <p>The various SHADOW_* styles are not yet implemented.</p> * <dl> * <dt><b>Styles:</b></dt> * <dd>SHADOW_ETCHED_IN, SHADOW_ETCHED_OUT, SHADOW_IN, SHADOW_OUT, SHADOW_NONE</dd> * <dt><b>Events:</b></dt> * <dd>(none)</dd> * </dl> * <p> * Note: Only one of the above styles may be specified. * </p><p> * IMPORTANT: This class is <em>not</em> intended to be subclassed. * </p> * <hr/> * Note: The styles <code>SHADOW_XXX</code> are not yet implemented in RWT. * @since 1.0 */ public class Group extends Composite { private String text; /** * Constructs a new instance of this class given its parent * and a style value describing its behavior and appearance. * <p> * The style value is either one of the style constants defined in * class <code>SWT</code> which is applicable to instances of this * class, or must be built by <em>bitwise OR</em>'ing together * (that is, using the <code>int</code> "|" operator) two or more * of those <code>SWT</code> style constants. The class description * lists the style constants that are applicable to the class. * Style bits are also inherited from superclasses. * </p> * <p>The various SHADOW_* styles are not yet implemented.</p> * * @param parent a composite control which will be the parent of the new instance (cannot be null) * @param style the style of control to construct * * @exception IllegalArgumentException <ul> * <li>ERROR_NULL_ARGUMENT - if the parent is null</li> * </ul> * @exception SWTException <ul> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li> * <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass</li> * </ul> * * <!--@see SWT#SHADOW_ETCHED_IN--> * <!--@see SWT#SHADOW_ETCHED_OUT--> * @see SWT#SHADOW_IN * @see SWT#SHADOW_OUT * @see SWT#SHADOW_NONE * @see Widget#checkSubclass * @see Widget#getStyle */ // TODO: [bm] implement shadow styles for Group public Group(Composite parent, int style) { super(parent, checkStyle(style)); text = ""; } /** * Sets the receiver's text, which is the string that will * be displayed as the receiver's <em>title</em>, to the argument, * which may not be null. The string may include the mnemonic character. * </p> * Mnemonics are indicated by an '&' that causes the next * character to be the mnemonic. When the user presses a * key sequence that matches the mnemonic, focus is assigned * to the first child of the group. On most platforms, the * mnemonic appears underlined but may be emphasised in a * platform specific manner. The mnemonic indicator character * '&' can be escaped by doubling it in the string, causing * a single '&' to be displayed. * </p> * @param text the new text * * @exception IllegalArgumentException <ul> * <li>ERROR_NULL_ARGUMENT - if the text is null</li> * </ul> * @exception SWTException <ul> * <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> * </ul> */ public void setText(String text) { checkWidget(); if (text == null) { SWT.error(SWT.ERROR_NULL_ARGUMENT); } this.text = text; } /** * Returns the receiver's text, which is the string that the * is used as the <em>title</em>. If the text has not previously * been set, returns an empty string. * * @return the text * * @exception SWTException <ul> * <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> * </ul> */ public String getText() { checkWidget(); return text; } @Override public Rectangle getClientArea() { checkWidget(); Rectangle bounds = getBounds(); BoxDimensions trimmings = getThemeAdapter().getTrimmingSize(this); int trimmingsWidth = trimmings.left + trimmings.right; int trimmingsHeight = trimmings.top + trimmings.bottom; BoxDimensions border = getBorder(); int borderWidth = border.left + border.right; int borderHeight = border.top + border.bottom; int width = Math.max(0, bounds.width - trimmingsWidth - borderWidth); int height = Math.max(0, bounds.height - trimmingsHeight - borderHeight); return new Rectangle(trimmings.left, trimmings.top, width, height); } @Override public Rectangle computeTrim(int x, int y, int width, int height) { BoxDimensions trimmings = getThemeAdapter().getTrimmingSize(this); int trimmingsWidth = trimmings.left + trimmings.right; int trimmingsHeight = trimmings.top + trimmings.bottom; BoxDimensions border = getBorder(); int borderWidth = border.left + border.right; int borderHeight = border.top + border.bottom; return super.computeTrim(x - trimmings.left - border.left, y - trimmings.top - border.top, width + trimmingsWidth + borderWidth, height + trimmingsHeight + borderHeight); } @Override public Point computeSize(int wHint, int hHint, boolean changed) { checkWidget(); Point result = super.computeSize(wHint, hHint, changed); int length = text.length(); if (length != 0) { Font font = getFont(); Point stringExtent = TextSizeUtil.stringExtent(font, text); BoxDimensions headTrimmings = getThemeAdapter().getHeaderTrimmingSize(this); int headerWidth = stringExtent.x + headTrimmings.left + headTrimmings.right; result.x = Math.max(result.x, headerWidth); } return result; } @Override @SuppressWarnings("unchecked") public <T> T getAdapter(Class<T> adapter) { if (adapter == WidgetLCA.class) { return (T) GroupLCA.INSTANCE; } return super.getAdapter(adapter); } private GroupThemeAdapter getThemeAdapter() { return (GroupThemeAdapter) getAdapter(ThemeAdapter.class); } ////////////////// // Helping methods @Override String getNameText() { return getText(); } private static int checkStyle(int style) { int result = style | SWT.NO_FOCUS; /* * Even though it is legal to create this widget with scroll bars, they * serve no useful purpose because they do not automatically scroll the * widget's client area. The fix is to clear the SWT style. */ return result & ~(SWT.H_SCROLL | SWT.V_SCROLL); } }