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.custom; import org.eclipse.rap.rwt.internal.lifecycle.WidgetLCA; import org.eclipse.rap.rwt.theme.BoxDimensions; import org.eclipse.rap.rwt.theme.ControlThemeAdapter; import org.eclipse.swt.SWT; import org.eclipse.swt.SWTException; import org.eclipse.swt.events.ControlAdapter; import org.eclipse.swt.events.ControlEvent; import org.eclipse.swt.graphics.Point; import org.eclipse.swt.graphics.Rectangle; import org.eclipse.swt.internal.custom.scrolledcompositekit.ScrolledCompositeLCA; import org.eclipse.swt.widgets.Composite; import org.eclipse.swt.widgets.Control; import org.eclipse.swt.widgets.Layout; import org.eclipse.swt.widgets.ScrollBar; import org.eclipse.swt.widgets.Shell; /** * A ScrolledComposite provides scrollbars and will scroll its content when the user * uses the scrollbars. * * * <p>There are two ways to use the ScrolledComposite: * * <p> * 1) Set the size of the control that is being scrolled and the ScrolledComposite * will show scrollbars when the contained control can not be fully seen. * * 2) The second way imitates the way a browser would work. Set the minimum size of * the control and the ScrolledComposite will show scroll bars if the visible area is * less than the minimum size of the control and it will expand the size of the control * if the visible area is greater than the minimum size. This requires invoking * both setMinWidth(), setMinHeight() and setExpandHorizontal(), setExpandVertical(). * * <dl> * <dt><b>Styles:</b><dd>H_SCROLL, V_SCROLL * </dl> * @since 1.0 */ public class ScrolledComposite extends Composite { private final ControlAdapter contentListener; Control content; int minHeight = 0; int minWidth = 0; boolean expandHorizontal; boolean expandVertical; boolean alwaysShowScroll; boolean showFocusedControl; /** * 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#H_SCROLL * @see SWT#V_SCROLL * @see #getStyle() */ public ScrolledComposite(Composite parent, int style) { super(parent, checkStyle(style)); super.setLayout(new ScrolledCompositeLayout()); contentListener = new ControlAdapter() { @Override public void controlResized(ControlEvent event) { layout(); // 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(); // ignore - ScrolledComposite manages its own layout } /** * Scrolls the content so that the specified point in the content is in the top * left corner. If no content has been set, nothing will occur. * * Negative values will be ignored. Values greater than the maximum scroll * distance will result in scrolling to the end of the scrollbar. * * @param origin the point on the content to appear in the top left corner * * @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 - value of origin is outside of content * </ul> */ public void setOrigin(Point origin) { setOrigin(origin.x, origin.y); } /** * Scrolls the content so that the specified point in the content is in the top * left corner. If no content has been set, nothing will occur. * * Negative values will be ignored. Values greater than the maximum scroll * distance will result in scrolling to the end of the scrollbar. * * @param left the x coordinate of the content to appear in the top left corner * * @param top the y coordinate of the content to appear in the top left corner * * @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 setOrigin(int left, int top) { checkWidget(); if (content != null && left >= 0 && top >= 0) { int x = left; int y = top; ScrollBar hBar = getHorizontalBar(); if (hBar != null) { hBar.setSelection(x); x = -hBar.getSelection(); } else { x = 0; } ScrollBar vBar = getVerticalBar(); if (vBar != null) { vBar.setSelection(y); y = -vBar.getSelection(); } else { y = 0; } content.setLocation(x, y); } } /** * Return the point in the content that currently appears in the top left * corner of the scrolled composite. * * @return the point in the content that currently appears in the top left * corner of the scrolled composite. If no content has been set, this returns * (0, 0). * * @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 Point getOrigin() { checkWidget(); Point result; if (content == null) { result = new Point(0, 0); } else { Point location = content.getLocation(); result = new Point(-location.x, -location.y); } return result; } /** * Set the Always Show Scrollbars flag. True if the scrollbars are * always shown even if they are not required. False if the scrollbars are only * visible when some part of the composite needs to be scrolled to be seen. * The H_SCROLL and V_SCROLL style bits are also required to enable scrollbars in the * horizontal and vertical directions. * * @param show true to show the scrollbars even when not required, false to show scrollbars only when required * * @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 setAlwaysShowScrollBars(boolean show) { checkWidget(); if (!show != !alwaysShowScroll) { alwaysShowScroll = show; ScrollBar hBar = getHorizontalBar(); if (hBar != null && alwaysShowScroll) { hBar.setVisible(true); } ScrollBar vBar = getVerticalBar(); if (vBar != null && alwaysShowScroll) { vBar.setVisible(true); } // layout( false ); layout(); } } /** * Returns the Always Show Scrollbars flag. True if the scrollbars are * always shown even if they are not required. False if the scrollbars are only * visible when some part of the composite needs to be scrolled to be seen. * The H_SCROLL and V_SCROLL style bits are also required to enable scrollbars in the * horizontal and vertical directions. * * @return the Always Show Scrollbars flag value */ public boolean getAlwaysShowScrollBars() { //checkWidget(); // <- commented in SWT return alwaysShowScroll; } /** * Returns <code>true</code> if the content control * will be expanded to fill available horizontal space. * * @return the receiver's horizontal expansion state * * @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 boolean getExpandHorizontal() { checkWidget(); return expandHorizontal; } /** * Returns <code>true</code> if the content control * will be expanded to fill available vertical space. * * @return the receiver's vertical expansion state * * @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 boolean getExpandVertical() { checkWidget(); return expandVertical; } /** * Configure the ScrolledComposite to resize the content object to be as wide as the * ScrolledComposite when the width of the ScrolledComposite is greater than the * minimum width specified in setMinWidth. If the ScrolledComposite is less than the * minimum width, the content will not be resized and instead the horizontal scroll bar will be * used to view the entire width. * If expand is false, this behaviour is turned off. By default, this behaviour is turned off. * * @param expand true to expand the content control to fill available horizontal space * * @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 setExpandHorizontal(boolean expand) { checkWidget(); if (expand != expandHorizontal) { expandHorizontal = expand; // layout( false ); layout(); } } /** * Configure the ScrolledComposite to resize the content object to be as tall as the * ScrolledComposite when the height of the ScrolledComposite is greater than the * minimum height specified in setMinHeight. If the ScrolledComposite is less than the * minimum height, the content will not be resized and instead the vertical scroll bar will be * used to view the entire height. * If expand is false, this behaviour is turned off. By default, this behaviour is turned off. * * @param expand true to expand the content control to fill available vertical space * * @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 setExpandVertical(boolean expand) { checkWidget(); if (expand != expandVertical) { expandVertical = expand; // layout( false ); layout(); } } /////////////////////// // Min width and height /** * Specify the minimum width at which the ScrolledComposite will begin scrolling the * content with the horizontal scroll bar. This value is only relevant if * setExpandHorizontal(true) has been set. * * @param width the minimum width or 0 for default width * * @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 setMinWidth(int width) { setMinSize(width, minHeight); } /** * Returns the minimum width of the content control. * * @return the minimum width * * @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 int getMinWidth() { checkWidget(); return minWidth; } /** * Specify the minimum height at which the ScrolledComposite will begin scrolling the * content with the vertical scroll bar. This value is only relevant if * setExpandVertical(true) has been set. * * @param height the minimum height or 0 for default height * * @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 setMinHeight(int height) { setMinSize(minWidth, height); } /** * Returns the minimum height of the content control. * * @return the minimum height * * @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 int getMinHeight() { checkWidget(); return minHeight; } /** * Specify the minimum width and height at which the ScrolledComposite will begin scrolling the * content with the horizontal scroll bar. This value is only relevant if * setExpandHorizontal(true) and setExpandVertical(true) have been set. * * @param size the minimum size or null for the default size * * @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 setMinSize(Point size) { if (size == null) { setMinSize(0, 0); } else { setMinSize(size.x, size.y); } } /** * Specify the minimum width and height at which the ScrolledComposite will begin scrolling the * content with the horizontal scroll bar. This value is only relevant if * setExpandHorizontal(true) and setExpandVertical(true) have been set. * * @param width the minimum width or 0 for default width * @param height the minimum height or 0 for default height * * @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 setMinSize(int width, int height) { checkWidget(); if (width != minWidth || height != minHeight) { minWidth = Math.max(0, width); minHeight = Math.max(0, height); // layout(false); layout(); } } ////////////////// // Content control /** * Set the content that will be scrolled. * * @param content the control to be displayed in the content area * * @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 setContent(Control content) { checkWidget(); if (this.content != null && !this.content.isDisposed()) { this.content.removeControlListener(contentListener); this.content.setBounds(new Rectangle(-200, -200, 0, 0)); } this.content = content; ScrollBar vBar = getVerticalBar(); ScrollBar hBar = getHorizontalBar(); if (this.content != null) { if (vBar != null) { vBar.setMaximum(0); vBar.setThumb(0); vBar.setSelection(0); } if (hBar != null) { hBar.setMaximum(0); hBar.setThumb(0); hBar.setSelection(0); } content.setLocation(0, 0); layout(); // layout(false); this.content.addControlListener(contentListener); } else { if (hBar != null) { hBar.setVisible(alwaysShowScroll); } if (vBar != null) { vBar.setVisible(alwaysShowScroll); } } } /** * Get the content that is being scrolled. * * @return the control displayed in the content area */ public Control getContent() { //checkWidget(); // <- commented in SWT return content; } /** * Configure the receiver to automatically scroll to a focused child control * to make it visible. * * If show is <code>false</code>, show a focused control is off. * By default, show a focused control is off. * * @param show <code>true</code> to show a focused control. * * @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> * * @since 1.3 */ public void setShowFocusedControl(boolean show) { checkWidget(); if (showFocusedControl != show) { showFocusedControl = show; if (showFocusedControl) { Control control = getDisplay().getFocusControl(); if (contains(control)) { showControl(control); } } } } /** * Returns <code>true</code> if the receiver automatically scrolls to a focused child control * to make it visible. Otherwise, returns <code>false</code>. * * @return a boolean indicating whether focused child controls are automatically scrolled into the viewport * * @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> * * @since 1.3 */ public boolean getShowFocusedControl() { checkWidget(); return showFocusedControl; } /** * Scrolls the content of the receiver so that the control is visible. * * @param control the control to be shown * * @exception IllegalArgumentException <ul> * <li>ERROR_NULL_ARGUMENT - if the control is null</li> * <li>ERROR_INVALID_ARGUMENT - if the control has been disposed</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> * * @since 1.3 */ public void showControl(Control control) { checkWidget(); if (control == null) { SWT.error(SWT.ERROR_NULL_ARGUMENT); } if (control.isDisposed()) { SWT.error(SWT.ERROR_INVALID_ARGUMENT); } if (!contains(control)) { SWT.error(SWT.ERROR_INVALID_ARGUMENT); } Rectangle itemRect = getDisplay().map(control.getParent(), this, control.getBounds()); Rectangle area = getClientArea(); Point origin = getOrigin(); if (itemRect.x < 0) { origin.x = Math.max(0, origin.x + itemRect.x); } else if (area.width < itemRect.x + itemRect.width) { int minWidth = Math.min(itemRect.width, area.width); origin.x = Math.max(0, origin.x + itemRect.x + minWidth - area.width); } if (itemRect.y < 0) { origin.y = Math.max(0, origin.y + itemRect.y); } else if (area.height < itemRect.y + itemRect.height) { int minHeight = Math.min(itemRect.height, area.height); origin.y = Math.max(0, origin.y + itemRect.y + minHeight - area.height); } setOrigin(origin); } boolean contains(Control control) { boolean result = false; if (control != null && !control.isDisposed()) { Composite parent = control.getParent(); while (parent != null && !(parent instanceof Shell) && !result) { if (this == parent) { result = true; } parent = parent.getParent(); } } return result; } @Override public void dispose() { if (!isDisposed()) { if (content != null && !content.isDisposed()) { content.removeControlListener(contentListener); } ScrollBar horizontalBar = getHorizontalBar(); if (horizontalBar != null) { horizontalBar.dispose(); } ScrollBar verticalBar = getVerticalBar(); if (verticalBar != null) { verticalBar.dispose(); } super.dispose(); } } @Override @SuppressWarnings("unchecked") public <T> T getAdapter(Class<T> adapter) { if (adapter == WidgetLCA.class) { return (T) ScrolledCompositeLCA.INSTANCE; } return super.getAdapter(adapter); } boolean needHScroll(Rectangle contentRect, boolean vVisible) { ScrollBar hBar = getHorizontalBar(); if (hBar == null) { return false; } Rectangle hostRect = getBounds(); BoxDimensions border = getAdapter(ControlThemeAdapter.class).getBorder(this); hostRect.width -= border.left + border.right; ScrollBar vBar = getVerticalBar(); if (vVisible && vBar != null) { hostRect.width -= vBar.getSize().x; } if (!expandHorizontal && contentRect.width > hostRect.width) { return true; } if (expandHorizontal && minWidth > hostRect.width) { return true; } return false; } boolean needVScroll(Rectangle contentRect, boolean hVisible) { ScrollBar vBar = getVerticalBar(); if (vBar == null) { return false; } Rectangle hostRect = getBounds(); BoxDimensions border = getAdapter(ControlThemeAdapter.class).getBorder(this); hostRect.height -= border.top + border.bottom; ScrollBar hBar = getHorizontalBar(); if (hVisible && hBar != null) { hostRect.height -= hBar.getSize().y; } if (!expandVertical && contentRect.height > hostRect.height) { return true; } if (expandVertical && minHeight > hostRect.height) { return true; } return false; } // //////////////// // Helping methods private static int checkStyle(int style) { int mask = SWT.H_SCROLL | SWT.V_SCROLL | SWT.BORDER | SWT.LEFT_TO_RIGHT | SWT.RIGHT_TO_LEFT; return style & mask; } }