Java tutorial
/******************************************************************************* * Copyright (c) 2000, 2018 IBM Corporation and others. * * This program and the accompanying materials * are made available under the terms of the Eclipse Public License 2.0 * which accompanies this distribution, and is available at * https://www.eclipse.org/legal/epl-2.0/ * * SPDX-License-Identifier: EPL-2.0 * * Contributors: * IBM Corporation - initial API and implementation *******************************************************************************/ package org.eclipse.swt.custom; import org.eclipse.swt.*; import org.eclipse.swt.graphics.*; import org.eclipse.swt.widgets.*; /** * Instances of this class implement a Composite that positions and sizes * children and allows programmatic control of layout and border parameters. * ViewForm is used in the workbench to lay out a view's label/menu/toolbar * local bar. * <p> * Note that although this class is a subclass of <code>Composite</code>, * it does not make sense to set a layout on it. * </p> * <dl> * <dt><b>Styles:</b></dt> * <dd>BORDER, FLAT</dd> * <dt><b>Events:</b></dt> * <dd>(None)</dd> * </dl> * <p> * IMPORTANT: This class is <em>not</em> intended to be subclassed. * </p> * * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a> * @noextend This class is not intended to be subclassed by clients. */ public class ViewForm extends Composite { /** * marginWidth specifies the number of points of horizontal margin * that will be placed along the left and right edges of the form. * * The default value is 0. */ public int marginWidth = 0; /** * marginHeight specifies the number of points of vertical margin * that will be placed along the top and bottom edges of the form. * * The default value is 0. */ public int marginHeight = 0; /** * horizontalSpacing specifies the number of points between the right * edge of one cell and the left edge of its neighbouring cell to * the right. * * The default value is 1. */ public int horizontalSpacing = 1; /** * verticalSpacing specifies the number of points between the bottom * edge of one cell and the top edge of its neighbouring cell underneath. * * The default value is 1. */ public int verticalSpacing = 1; /** * Color of innermost line of drop shadow border. * * NOTE This field is badly named and can not be fixed for backwards compatibility. * It should be capitalized. * * @deprecated */ @Deprecated public static RGB borderInsideRGB = new RGB(132, 130, 132); /** * Color of middle line of drop shadow border. * * NOTE This field is badly named and can not be fixed for backwards compatibility. * It should be capitalized. * * @deprecated */ @Deprecated public static RGB borderMiddleRGB = new RGB(143, 141, 138); /** * Color of outermost line of drop shadow border. * * NOTE This field is badly named and can not be fixed for backwards compatibility. * It should be capitalized. * * @deprecated */ @Deprecated public static RGB borderOutsideRGB = new RGB(171, 168, 165); // SWT widgets Control topLeft; Control topCenter; Control topRight; Control content; // Configuration and state info boolean separateTopCenter = false; boolean showBorder = false; int separator = -1; int borderTop = 0; int borderBottom = 0; int borderLeft = 0; int borderRight = 0; int highlight = 0; Point oldSize; Color selectionBackground; Listener listener; static final int OFFSCREEN = -200; static final int BORDER1_COLOR = SWT.COLOR_WIDGET_NORMAL_SHADOW; static final int SELECTION_BACKGROUND = SWT.COLOR_LIST_BACKGROUND; /** * 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> * * @param parent a widget which will be the parent of the new instance (cannot be null) * @param style the style of widget 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> * </ul> * * @see SWT#BORDER * @see SWT#FLAT * @see #getStyle() */ public ViewForm(Composite parent, int style) { super(parent, checkStyle(style)); super.setLayout(new ViewFormLayout()); setBorderVisible((style & SWT.BORDER) != 0); listener = e -> { switch (e.type) { case SWT.Dispose: onDispose(e); break; case SWT.Paint: onPaint(e.gc); break; case SWT.Resize: onResize(); break; } }; int[] events = new int[] { SWT.Dispose, SWT.Paint, SWT.Resize }; for (int i = 0; i < events.length; i++) { addListener(events[i], listener); } } static int checkStyle(int style) { int mask = SWT.FLAT | SWT.LEFT_TO_RIGHT | SWT.RIGHT_TO_LEFT; return style & mask | SWT.NO_REDRAW_RESIZE; } //protected void checkSubclass () { // String name = getClass().getName (); // String validName = ViewForm.class.getName(); // if (!validName.equals(name)) { // SWT.error (SWT.ERROR_INVALID_SUBCLASS); // } //} @Override public Rectangle computeTrim(int x, int y, int width, int height) { checkWidget(); int trimX = x - borderLeft - highlight; int trimY = y - borderTop - highlight; int trimWidth = width + borderLeft + borderRight + 2 * highlight; int trimHeight = height + borderTop + borderBottom + 2 * highlight; return new Rectangle(trimX, trimY, trimWidth, trimHeight); } @Override public Rectangle getClientArea() { checkWidget(); Rectangle clientArea = super.getClientArea(); clientArea.x += borderLeft; clientArea.y += borderTop; clientArea.width -= borderLeft + borderRight; clientArea.height -= borderTop + borderBottom; return clientArea; } /** * Returns the content area. * * @return the control in the content area of the pane or null */ public Control getContent() { /* * This call is intentionally commented out, to allow this getter method to be * called from a thread which is different from one that created the parent. */ //checkWidget(); return content; } /** * Returns Control that appears in the top center of the pane. * Typically this is a toolbar. * * @return the control in the top center of the pane or null */ public Control getTopCenter() { /* * This call is intentionally commented out, to allow this getter method to be * called from a thread which is different from one that created the widget. */ //checkWidget(); return topCenter; } /** * Returns the Control that appears in the top left corner of the pane. * Typically this is a label such as CLabel. * * @return the control in the top left corner of the pane or null */ public Control getTopLeft() { /* * This call is intentionally commented out, to allow this getter method to be * called from a thread which is different from one that created the widget. */ //checkWidget(); return topLeft; } /** * Returns the control in the top right corner of the pane. * Typically this is a Close button or a composite with a Menu and Close button. * * @return the control in the top right corner of the pane or null */ public Control getTopRight() { /* * This call is intentionally commented out, to allow this getter method to be * called from a thread which is different from one that created the widget. */ //checkWidget(); return topRight; } void onDispose(Event event) { removeListener(SWT.Dispose, listener); notifyListeners(SWT.Dispose, event); event.type = SWT.None; topLeft = null; topCenter = null; topRight = null; content = null; oldSize = null; selectionBackground = null; } void onPaint(GC gc) { Color gcForeground = gc.getForeground(); Point size = getSize(); Color border = getDisplay().getSystemColor(BORDER1_COLOR); if (showBorder) { gc.setForeground(border); gc.drawRectangle(0, 0, size.x - 1, size.y - 1); if (highlight > 0) { int x1 = 1; int y1 = 1; int x2 = size.x - 1; int y2 = size.y - 1; int[] shape = new int[] { x1, y1, x2, y1, x2, y2, x1, y2, x1, y1 + highlight, x1 + highlight, y1 + highlight, x1 + highlight, y2 - highlight, x2 - highlight, y2 - highlight, x2 - highlight, y1 + highlight, x1, y1 + highlight }; Color highlightColor = getDisplay().getSystemColor(SWT.COLOR_LIST_SELECTION); gc.setBackground(highlightColor); gc.fillPolygon(shape); } } if (separator > -1) { gc.setForeground(border); gc.drawLine(borderLeft + highlight, separator, size.x - borderLeft - borderRight - highlight, separator); } gc.setForeground(gcForeground); } void onResize() { Point size = getSize(); if (oldSize == null || oldSize.x == 0 || oldSize.y == 0) { redraw(); } else { int width = 0; if (oldSize.x < size.x) { width = size.x - oldSize.x + borderRight + highlight; } else if (oldSize.x > size.x) { width = borderRight + highlight; } redraw(size.x - width, 0, width, size.y, false); int height = 0; if (oldSize.y < size.y) { height = size.y - oldSize.y + borderBottom + highlight; } if (oldSize.y > size.y) { height = borderBottom + highlight; } redraw(0, size.y - height, size.x, height, false); } oldSize = size; } /** * Sets the content. * Setting the content to null will remove it from * the pane - however, the creator of the content must dispose of the content. * * @param content the control to be displayed in the content area or null * * @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> * <li>ERROR_INVALID_ARGUMENT - if the control is not a child of this ViewForm</li> * </ul> */ public void setContent(Control content) { checkWidget(); if (content != null && content.getParent() != this) { SWT.error(SWT.ERROR_INVALID_ARGUMENT); } if (this.content != null && !this.content.isDisposed()) { this.content.setBounds(OFFSCREEN, OFFSCREEN, 0, 0); } this.content = content; layout(false); } /** * Sets the layout which is associated with the receiver to be * the argument which may be null. * <p> * Note: No Layout can be set on this Control because it already * manages the size and position of its children. * </p> * * @param layout the receiver's new layout or null * * @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> */ @Override public void setLayout(Layout layout) { checkWidget(); return; } void setSelectionBackground(Color color) { checkWidget(); if (selectionBackground == color) return; if (color == null) color = getDisplay().getSystemColor(SELECTION_BACKGROUND); selectionBackground = color; redraw(); } /** * Set the control that appears in the top center of the pane. * Typically this is a toolbar. * The topCenter is optional. Setting the topCenter to null will remove it from * the pane - however, the creator of the topCenter must dispose of the topCenter. * * @param topCenter the control to be displayed in the top center or null * * @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> * <li>ERROR_INVALID_ARGUMENT - if the control is not a child of this ViewForm</li> * </ul> */ public void setTopCenter(Control topCenter) { checkWidget(); if (topCenter != null && topCenter.getParent() != this) { SWT.error(SWT.ERROR_INVALID_ARGUMENT); } if (this.topCenter != null && !this.topCenter.isDisposed()) { Point size = this.topCenter.getSize(); this.topCenter.setLocation(OFFSCREEN - size.x, OFFSCREEN - size.y); } this.topCenter = topCenter; layout(false); } /** * Set the control that appears in the top left corner of the pane. * Typically this is a label such as CLabel. * The topLeft is optional. Setting the top left control to null will remove it from * the pane - however, the creator of the control must dispose of the control. * * @param c the control to be displayed in the top left corner or null * * @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> * <li>ERROR_INVALID_ARGUMENT - if the control is not a child of this ViewForm</li> * </ul> */ public void setTopLeft(Control c) { checkWidget(); if (c != null && c.getParent() != this) { SWT.error(SWT.ERROR_INVALID_ARGUMENT); } if (this.topLeft != null && !this.topLeft.isDisposed()) { Point size = this.topLeft.getSize(); this.topLeft.setLocation(OFFSCREEN - size.x, OFFSCREEN - size.y); } this.topLeft = c; layout(false); } /** * Set the control that appears in the top right corner of the pane. * Typically this is a Close button or a composite with a Menu and Close button. * The topRight is optional. Setting the top right control to null will remove it from * the pane - however, the creator of the control must dispose of the control. * * @param c the control to be displayed in the top right corner or null * * @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> * <li>ERROR_INVALID_ARGUMENT - if the control is not a child of this ViewForm</li> * </ul> */ public void setTopRight(Control c) { checkWidget(); if (c != null && c.getParent() != this) { SWT.error(SWT.ERROR_INVALID_ARGUMENT); } if (this.topRight != null && !this.topRight.isDisposed()) { Point size = this.topRight.getSize(); this.topRight.setLocation(OFFSCREEN - size.x, OFFSCREEN - size.y); } this.topRight = c; layout(false); } /** * Specify whether the border should be displayed or not. * * @param show true if the border should be displayed * * @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 setBorderVisible(boolean show) { checkWidget(); if (showBorder == show) return; showBorder = show; if (showBorder) { borderLeft = borderTop = borderRight = borderBottom = 1; if ((getStyle() & SWT.FLAT) == 0) highlight = 2; } else { borderBottom = borderTop = borderLeft = borderRight = 0; highlight = 0; } layout(false); redraw(); } /** * If true, the topCenter will always appear on a separate line by itself, otherwise the * topCenter will appear in the top row if there is room and will be moved to the second row if * required. * * @param show true if the topCenter will always appear on a separate line by itself * * @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 setTopCenterSeparate(boolean show) { checkWidget(); separateTopCenter = show; layout(false); } }