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SWT is an open source widget toolkit for Java designed to provide efficient, portable access to the user-interface facilities of the operating systems on which it is implemented.
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/*******************************************************************************
* Copyright (c) 2000, 2012 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
*******************************************************************************/
package org.eclipse.swt.custom;
import org.eclipse.swt.*;
import org.eclipse.swt.events.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.widgets.*;
/**
* A ScrolledComposite provides scrollbars and will scroll its content when the user
* uses the scrollbars.
*
*
* There are two ways to use the ScrolledComposite:
*
*
* 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().
*
*
* public static void main (String [] args) {
* Display display = new Display ();
* Color red = display.getSystemColor(SWT.COLOR_RED);
* Color blue = display.getSystemColor(SWT.COLOR_BLUE);
* Shell shell = new Shell (display);
* shell.setLayout(new FillLayout());
*
* // set the size of the scrolled content - method 1
* final ScrolledComposite sc1 = new ScrolledComposite(shell, SWT.H_SCROLL | SWT.V_SCROLL | SWT.BORDER);
* final Composite c1 = new Composite(sc1, SWT.NONE);
* sc1.setContent(c1);
* c1.setBackground(red);
* GridLayout layout = new GridLayout();
* layout.numColumns = 4;
* c1.setLayout(layout);
* Button b1 = new Button (c1, SWT.PUSH);
* b1.setText("first button");
* c1.setSize(c1.computeSize(SWT.DEFAULT, SWT.DEFAULT));
*
* // set the minimum width and height of the scrolled content - method 2
* final ScrolledComposite sc2 = new ScrolledComposite(shell, SWT.H_SCROLL | SWT.V_SCROLL | SWT.BORDER);
* sc2.setExpandHorizontal(true);
* sc2.setExpandVertical(true);
* final Composite c2 = new Composite(sc2, SWT.NONE);
* sc2.setContent(c2);
* c2.setBackground(blue);
* layout = new GridLayout();
* layout.numColumns = 4;
* c2.setLayout(layout);
* Button b2 = new Button (c2, SWT.PUSH);
* b2.setText("first button");
* sc2.setMinSize(c2.computeSize(SWT.DEFAULT, SWT.DEFAULT));
*
* Button add = new Button (shell, SWT.PUSH);
* add.setText("add children");
* final int[] index = new int[]{0};
* add.addListener(SWT.Selection, new Listener() {
* public void handleEvent(Event e) {
* index[0]++;
* Button button = new Button(c1, SWT.PUSH);
* button.setText("button "+index[0]);
* // reset size of content so children can be seen - method 1
* c1.setSize(c1.computeSize(SWT.DEFAULT, SWT.DEFAULT));
* c1.layout();
*
* button = new Button(c2, SWT.PUSH);
* button.setText("button "+index[0]);
* // reset the minimum width and height so children can be seen - method 2
* sc2.setMinSize(c2.computeSize(SWT.DEFAULT, SWT.DEFAULT));
* c2.layout();
* }
* });
*
* shell.open ();
* while (!shell.isDisposed ()) {
* if (!display.readAndDispatch ()) display.sleep ();
* }
* display.dispose ();
* }
*
* - Styles:
- H_SCROLL, V_SCROLL
*
*
* @see ScrolledComposite snippets
* @see Sample code and further information
*/
public class ScrolledComposite extends Composite {
Control content;
Listener contentListener;
Listener filter;
int minHeight = 0;
int minWidth = 0;
boolean expandHorizontal = false;
boolean expandVertical = false;
boolean alwaysShowScroll = false;
boolean showFocusedControl = false;
boolean showNextFocusedControl = true;
/**
* Constructs a new instance of this class given its parent
* and a style value describing its behavior and appearance.
*
* The style value is either one of the style constants defined in
* class SWT which is applicable to instances of this
* class, or must be built by bitwise OR'ing together
* (that is, using the int "|" operator) two or more
* of those SWT 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 widget which will be the parent of the new instance (cannot be null)
* @param style the style of widget to construct
*
* @exception IllegalArgumentException
* - ERROR_NULL_ARGUMENT - if the parent is null
*
* @exception SWTException
* - ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent
*
*
* @see SWT#H_SCROLL
* @see SWT#V_SCROLL
* @see #getStyle()
*/
public ScrolledComposite(Composite parent, int style) {
super(parent, checkStyle(style));
super.setLayout(new ScrolledCompositeLayout());
ScrollBar hBar = getHorizontalBar ();
if (hBar != null) {
hBar.setVisible(false);
hBar.addListener (SWT.Selection, new Listener () {
public void handleEvent (Event e) {
hScroll();
}
});
}
ScrollBar vBar = getVerticalBar ();
if (vBar != null) {
vBar.setVisible(false);
vBar.addListener (SWT.Selection, new Listener () {
public void handleEvent (Event e) {
vScroll();
}
});
}
contentListener = new Listener() {
public void handleEvent(Event e) {
if (e.type != SWT.Resize) return;
layout(false);
}
};
filter = new Listener() {
public void handleEvent(Event event) {
if (event.type == SWT.FocusIn) {
if (!showNextFocusedControl) {
showNextFocusedControl = true;
} else if (event.widget instanceof Control) {
Control control = (Control) event.widget;
if (contains(control)) showControl(control);
}
} else {
Widget w = event.widget;
if (w instanceof Control) {
showNextFocusedControl = w.getDisplay().getActiveShell() == ((Control) w).getShell();
}
}
}
};
addDisposeListener(new DisposeListener() {
public void widgetDisposed(DisposeEvent e) {
getDisplay().removeFilter(SWT.FocusIn, filter);
getDisplay().removeFilter(SWT.FocusOut, filter);
}
});
}
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;
}
boolean contains(Control control) {
if (control == null || control.isDisposed()) return false;
Composite parent = control.getParent();
while (parent != null && !(parent instanceof Shell)) {
if (this == parent) return true;
parent = parent.getParent();
}
return false;
}
/**
* 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();
return alwaysShowScroll;
}
/**
* Returns true if the content control
* will be expanded to fill available horizontal space.
*
* @return the receiver's horizontal expansion state
*
* @exception SWTException
* - ERROR_WIDGET_DISPOSED - if the receiver has been disposed
* - ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
*
*
* @since 3.2
*/
public boolean getExpandHorizontal() {
checkWidget();
return expandHorizontal;
}
/**
* Returns true if the content control
* will be expanded to fill available vertical space.
*
* @return the receiver's vertical expansion state
*
* @exception SWTException
* - ERROR_WIDGET_DISPOSED - if the receiver has been disposed
* - ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
*
*
* @since 3.2
*/
public boolean getExpandVertical() {
checkWidget();
return expandVertical;
}
/**
* Returns the minimum width of the content control.
*
* @return the minimum width
*
* @exception SWTException
* - ERROR_WIDGET_DISPOSED - if the receiver has been disposed
* - ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
*
*
* @since 3.2
*/
public int getMinWidth() {
checkWidget();
return minWidth;
}
/**
* Returns the minimum height of the content control.
*
* @return the minimum height
*
* @exception SWTException
* - ERROR_WIDGET_DISPOSED - if the receiver has been disposed
* - ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
*
*
* @since 3.2
*/
public int getMinHeight() {
checkWidget();
return minHeight;
}
/**
* Get the content that is being scrolled.
*
* @return the control displayed in the content area
*/
public Control getContent() {
//checkWidget();
return content;
}
/**
* Returns true if the receiver automatically scrolls to a focused child control
* to make it visible. Otherwise, returns false.
*
* @return a boolean indicating whether focused child controls are automatically scrolled into the viewport
*
* @exception SWTException
* - ERROR_WIDGET_DISPOSED - if the receiver has been disposed
* - ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
*
*
* @since 3.4
*/
public boolean getShowFocusedControl() {
checkWidget();
return showFocusedControl;
}
void hScroll() {
if (content == null) return;
Point location = content.getLocation ();
ScrollBar hBar = getHorizontalBar ();
int hSelection = hBar.getSelection ();
content.setLocation (-hSelection, location.y);
}
boolean needHScroll(Rectangle contentRect, boolean vVisible) {
ScrollBar hBar = getHorizontalBar();
if (hBar == null) return false;
Rectangle hostRect = getBounds();
int border = getBorderWidth();
hostRect.width -= 2*border;
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();
int border = getBorderWidth();
hostRect.height -= 2*border;
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;
}
/**
* 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
* - ERROR_WIDGET_DISPOSED - if the receiver has been disposed
* - ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
*
*
* @since 2.0
*/
public Point getOrigin() {
checkWidget();
if (content == null) return new Point(0, 0);
Point location = content.getLocation();
return new Point(-location.x, -location.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 origin the point on the content to appear in the top left corner
*
* @exception SWTException
* - ERROR_WIDGET_DISPOSED - if the receiver has been disposed
* - ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
* - ERROR_INVALID_ARGUMENT - value of origin is outside of content
*
* @since 2.0
*/
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 x the x coordinate of the content to appear in the top left corner
*
* @param y the y coordinate of the content to appear in the top left corner
*
* @exception SWTException
* - ERROR_WIDGET_DISPOSED - if the receiver has been disposed
* - ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
*
*
* @since 2.0
*/
public void setOrigin(int x, int y) {
checkWidget();
if (content == null) return;
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);
}
/**
* 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
* - ERROR_WIDGET_DISPOSED - if the receiver has been disposed
* - ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
*
*/
public void setAlwaysShowScrollBars(boolean show) {
checkWidget();
if (show == alwaysShowScroll) return;
alwaysShowScroll = show;
ScrollBar hBar = getHorizontalBar ();
if (hBar != null && alwaysShowScroll) hBar.setVisible(true);
ScrollBar vBar = getVerticalBar ();
if (vBar != null && alwaysShowScroll) vBar.setVisible(true);
layout(false);
}
/**
* Set the content that will be scrolled.
*
* @param content the control to be displayed in the content area
*
* @exception SWTException
* - ERROR_WIDGET_DISPOSED - if the receiver has been disposed
* - ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
*
*/
public void setContent(Control content) {
checkWidget();
if (this.content != null && !this.content.isDisposed()) {
this.content.removeListener(SWT.Resize, 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(false);
this.content.addListener(SWT.Resize, contentListener);
} else {
if (hBar != null) hBar.setVisible(alwaysShowScroll);
if (vBar != null) vBar.setVisible(alwaysShowScroll);
}
}
/**
* 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
* - ERROR_WIDGET_DISPOSED - if the receiver has been disposed
* - ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
*
*/
public void setExpandHorizontal(boolean expand) {
checkWidget();
if (expand == expandHorizontal) return;
expandHorizontal = expand;
layout(false);
}
/**
* 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
* - ERROR_WIDGET_DISPOSED - if the receiver has been disposed
* - ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
*
*/
public void setExpandVertical(boolean expand) {
checkWidget();
if (expand == expandVertical) return;
expandVertical = expand;
layout(false);
}
/**
* Sets the layout which is associated with the receiver to be
* the argument which may be null.
*
* Note: No Layout can be set on this Control because it already
* manages the size and position of its children.
*
*
* @param layout the receiver's new layout or null
*
* @exception SWTException
* - ERROR_WIDGET_DISPOSED - if the receiver has been disposed
* - ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
*
*/
public void setLayout (Layout layout) {
checkWidget();
return;
}
/**
* 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
* - ERROR_WIDGET_DISPOSED - if the receiver has been disposed
* - ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
*
*/
public void setMinHeight(int height) {
setMinSize(minWidth, height);
}
/**
* 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
* - ERROR_WIDGET_DISPOSED - if the receiver has been disposed
* - ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
*
*/
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
* - ERROR_WIDGET_DISPOSED - if the receiver has been disposed
* - ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
*
*/
public void setMinSize(int width, int height) {
checkWidget();
if (width == minWidth && height == minHeight) return;
minWidth = Math.max(0, width);
minHeight = Math.max(0, height);
layout(false);
}
/**
* 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
* - ERROR_WIDGET_DISPOSED - if the receiver has been disposed
* - ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
*
*/
public void setMinWidth(int width) {
setMinSize(width, minHeight);
}
/**
* Configure the receiver to automatically scroll to a focused child control
* to make it visible.
*
* If show is false, show a focused control is off.
* By default, show a focused control is off.
*
* @param show true to show a focused control.
*
* @exception SWTException
* - ERROR_WIDGET_DISPOSED - if the receiver has been disposed
* - ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
*
*
* @since 3.4
*/
public void setShowFocusedControl(boolean show) {
checkWidget();
if (showFocusedControl == show) return;
Display display = getDisplay();
display.removeFilter(SWT.FocusIn, filter);
display.removeFilter(SWT.FocusOut, filter);
showFocusedControl = show;
if (!showFocusedControl) return;
display.addFilter(SWT.FocusIn, filter);
display.addFilter(SWT.FocusOut, filter);
Control control = display.getFocusControl();
if (contains(control)) showControl(control);
}
/**
* Scrolls the content of the receiver so that the control is visible.
*
* @param control the control to be shown
*
* @exception IllegalArgumentException
* - ERROR_NULL_ARGUMENT - if the control is null
* - ERROR_INVALID_ARGUMENT - if the control has been disposed
*
* @exception SWTException
* - ERROR_WIDGET_DISPOSED - if the receiver has been disposed
* - ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
*
*
* @since 3.4
*/
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) origin.x = Math.max(0, origin.x + itemRect.x + Math.min(itemRect.width, area.width) - area.width);
}
if (itemRect.y < 0) {
origin.y = Math.max(0, origin.y + itemRect.y);
} else {
if (area.height < itemRect.y + itemRect.height) origin.y = Math.max(0, origin.y + itemRect.y + Math.min(itemRect.height, area.height) - area.height);
}
setOrigin(origin);
}
void vScroll() {
if (content == null) return;
Point location = content.getLocation ();
ScrollBar vBar = getVerticalBar ();
int vSelection = vBar.getSelection ();
content.setLocation (location.x, -vSelection);
}
}