Java tutorial
/******************************************************************************* * Copyright (c) 2008, 2016 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 static org.eclipse.rap.rwt.internal.textsize.TextSizeUtil.stringExtent; import java.util.StringTokenizer; import org.eclipse.rap.rwt.RWT; import org.eclipse.rap.rwt.widgets.DialogCallback; import org.eclipse.swt.SWT; import org.eclipse.swt.SWTException; import org.eclipse.swt.events.SelectionAdapter; import org.eclipse.swt.events.SelectionEvent; import org.eclipse.swt.graphics.Font; import org.eclipse.swt.graphics.Image; import org.eclipse.swt.graphics.Point; import org.eclipse.swt.graphics.Rectangle; import org.eclipse.swt.layout.GridData; import org.eclipse.swt.layout.GridLayout; /** * Instances of this class are used to inform or warn the user. * <dl> * <dt><b>Styles:</b></dt> * <dd>ICON_ERROR, ICON_INFORMATION, ICON_QUESTION, ICON_WARNING, ICON_WORKING</dd> * <dd>OK, OK | CANCEL</dd> * <dd>YES | NO, YES | NO | CANCEL</dd> * <dd>RETRY | CANCEL</dd> * <dd>ABORT | RETRY | IGNORE</dd> * <dt><b>Events:</b></dt> * <dd>(none)</dd> * </dl> * <p> * Note: Only one of the styles ICON_ERROR, ICON_INFORMATION, ICON_QUESTION, * ICON_WARNING and ICON_WORKING may be specified. * </p><p> * IMPORTANT: This class is intended to be subclassed <em>only</em> * within the SWT implementation. * </p> * @since 1.2 */ public class MessageBox extends Dialog { private static final int SPACING = 20; private static final int BUTTON_WIDTH = 61; private static final int MAX_WIDTH = 640; private Image image; private String message; private boolean markupEnabled; /** * Constructs a new instance of this class given only its parent. * * @param parent a shell which will be the parent of the new instance * * @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> */ public MessageBox(Shell parent) { this(parent, SWT.OK | SWT.ICON_INFORMATION | SWT.APPLICATION_MODAL); } /** * 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. * * @param parent a shell which will be the parent of the new instance * @param style the style of dialog 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> */ public MessageBox(Shell parent, int style) { super(parent, checkStyle(style)); checkSubclass(); message = ""; } /** * Returns the dialog's message, or an empty string if it does not have one. * The message is a description of the purpose for which the dialog was opened. * This message will be visible in the dialog while it is open. * * @return the message */ public String getMessage() { return message; } /** * Sets the dialog's message, which is a description of * the purpose for which it was opened. This message will be * visible on the dialog while it is open. * * @param string the message * * @exception IllegalArgumentException <ul> * <li>ERROR_NULL_ARGUMENT - if the string is null</li> * </ul> */ public void setMessage(String string) { if (string == null) { SWT.error(SWT.ERROR_NULL_ARGUMENT); } message = string; } /** * Controls whether the use of <em>markup</em> in message is enabled. Once the markup in message * is enabled it's not possible to disable it. * * @param markupEnabled true to enable the markup in message * * @since 3.2 */ public void setMarkupEnabled(boolean markupEnabled) { if (!this.markupEnabled) { this.markupEnabled = markupEnabled; } } /** * Makes the dialog visible and brings it to the front * of the display. * * <!-- Begin RAP specific --> * <p><strong>RAP Note:</strong> This method is not supported when running the application in * JEE_COMPATIBILITY mode. Use <code>Dialog#open(DialogCallback)</code> instead.</p> * <!-- End RAP specific --> * * @return the ID of the button that was selected to dismiss the * message box (e.g. SWT.OK, SWT.CANCEL, etc.) * * @exception SWTException <ul> * <li>ERROR_WIDGET_DISPOSED - if the dialog has been disposed</li> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the dialog</li> * </ul> * @exception UnsupportedOperationException when running the application in JEE_COMPATIBILITY mode * * @see org.eclipse.rap.rwt.application.Application.OperationMode * @see #open(DialogCallback) */ public int open() { checkOperationMode(); prepareOpen(); runEventLoop(shell); return returnCode; } @Override protected void prepareOpen() { determineImageFromStyle(); shell = new Shell(parent, SWT.TITLE | SWT.BORDER | SWT.APPLICATION_MODAL); shell.setText(title); createControls(); shell.setBounds(computeShellBounds()); shell.pack(); } private void determineImageFromStyle() { image = null; int systemImageId = -1; if ((style & SWT.ICON_ERROR) != 0) { systemImageId = SWT.ICON_ERROR; } else if ((style & SWT.ICON_INFORMATION) != 0) { systemImageId = SWT.ICON_INFORMATION; } else if ((style & SWT.ICON_QUESTION) != 0) { systemImageId = SWT.ICON_QUESTION; } else if ((style & SWT.ICON_WARNING) != 0) { systemImageId = SWT.ICON_WARNING; } else if ((style & SWT.ICON_WORKING) != 0) { systemImageId = SWT.ICON_WORKING; } if (systemImageId != -1) { image = parent.getDisplay().getSystemImage(systemImageId); } } private Rectangle computeShellBounds() { Rectangle result = new Rectangle(0, 0, 0, 0); Point preferredSize = shell.computeSize(SWT.DEFAULT, SWT.DEFAULT); Rectangle displaySize = parent.getDisplay().getBounds(); result.x = (displaySize.width - preferredSize.x) / 2 + displaySize.x; result.y = (displaySize.height - preferredSize.y) / 2 + displaySize.y; result.width = Math.min(preferredSize.x, MAX_WIDTH); result.height = preferredSize.y; return result; } private void createControls() { shell.setLayout(new GridLayout(2, false)); createImage(); createText(); createButtons(); } private void createText() { Label textLabel = new Label(shell, SWT.WRAP); if (markupEnabled) { textLabel.setData(RWT.MARKUP_ENABLED, Boolean.TRUE); } GridData data = new GridData(GridData.HORIZONTAL_ALIGN_FILL); int imageWidth = image == null ? 0 : image.getBounds().width; int maxTextWidth = MAX_WIDTH - imageWidth - SPACING; int maxLineWidth = getMaxMessageLineWidth(); if (maxLineWidth > maxTextWidth) { data.widthHint = maxTextWidth; } textLabel.setLayoutData(data); textLabel.setText(message); } private void createImage() { if (image != null) { Label label = new Label(shell, SWT.CENTER); GridData data = new GridData(SWT.CENTER, SWT.TOP, false, false); data.widthHint = image.getBounds().width + SPACING; label.setLayoutData(data); label.setImage(image); } } private void createButtons() { Composite buttonArea = new Composite(shell, SWT.NONE); buttonArea.setLayout(new GridLayout(0, true)); GridData buttonData = new GridData(SWT.CENTER, SWT.CENTER, true, false); buttonData.horizontalSpan = 2; buttonArea.setLayoutData(buttonData); createButton(buttonArea, SWT.getMessage("SWT_Yes"), SWT.YES); createButton(buttonArea, SWT.getMessage("SWT_No"), SWT.NO); createButton(buttonArea, SWT.getMessage("SWT_OK"), SWT.OK); createButton(buttonArea, SWT.getMessage("SWT_Abort"), SWT.ABORT); createButton(buttonArea, SWT.getMessage("SWT_Retry"), SWT.RETRY); createButton(buttonArea, SWT.getMessage("SWT_Cancel"), SWT.CANCEL); createButton(buttonArea, SWT.getMessage("SWT_Ignore"), SWT.IGNORE); buttonArea.getChildren()[0].forceFocus(); } private void createButton(Composite parent, String text, final int buttonId) { if ((style & buttonId) == buttonId) { ((GridLayout) parent.getLayout()).numColumns++; Button result = new Button(parent, SWT.PUSH); GridData data = new GridData(GridData.HORIZONTAL_ALIGN_FILL); int widthHint = convertHorizontalDLUsToPixels(shell, BUTTON_WIDTH); Point minSize = result.computeSize(SWT.DEFAULT, SWT.DEFAULT, true); data.widthHint = Math.max(widthHint, minSize.x); result.setLayoutData(data); result.setText(text); result.addSelectionListener(new SelectionAdapter() { @Override public void widgetSelected(SelectionEvent event) { MessageBox.this.returnCode = buttonId; shell.close(); } }); } } private int getMaxMessageLineWidth() { int result = 0; Font font = shell.getFont(); String lineSeparator = markupEnabled ? "<br/>" : "\n"; StringTokenizer tokenizer = new StringTokenizer(message, lineSeparator); while (tokenizer.hasMoreTokens()) { String line = tokenizer.nextToken(); int lineWidth = stringExtent(font, line, markupEnabled).x; result = Math.max(result, lineWidth); } return result; } private static int checkStyle(int style) { int chkStyle = 0; int mask = SWT.YES | SWT.NO | SWT.OK | SWT.CANCEL | SWT.ABORT | SWT.RETRY | SWT.IGNORE; int bits = style & mask; if (bits == SWT.OK || bits == (SWT.OK | SWT.CANCEL)) { chkStyle = style; } else if (bits == (SWT.YES | SWT.NO) || bits == (SWT.YES | SWT.NO | SWT.CANCEL)) { chkStyle = style; } else if (bits == (SWT.RETRY | SWT.CANCEL) || bits == (SWT.ABORT | SWT.RETRY | SWT.IGNORE)) { chkStyle = style; } else { chkStyle = (style & ~mask) | SWT.OK; } return chkStyle; } }