Java tutorial
/******************************************************************************* * Copyright (c) 2008, 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.theme.BoxDimensions; import org.eclipse.swt.SWT; import org.eclipse.swt.SWTException; import org.eclipse.swt.events.SelectionListener; import org.eclipse.swt.graphics.Point; import org.eclipse.swt.internal.widgets.scalekit.ScaleLCA; /** * Instances of the receiver represent a selectable user interface object that * present a range of continuous numeric values. * <dl> * <dt><b>Styles:</b></dt> * <dd>HORIZONTAL, VERTICAL</dd> * <dt><b>Events:</b></dt> * <dd>Selection</dd> * </dl> * <p> * Note: Only one of the styles HORIZONTAL and VERTICAL may be specified. * </p> * <p> * <p> * IMPORTANT: This class is intended to be subclassed <em>only</em> within the * SWT implementation. * </p> * * @since 1.2 */ public class Scale extends Control { private final Point PREFERRED_SIZE = new Point(160, 41); private int increment; private int maximum; private int minimum; private int pageIncrement; private int selection; /** * 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 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#HORIZONTAL * @see SWT#VERTICAL * @see Widget#checkSubclass * @see Widget#getStyle */ public Scale(Composite parent, int style) { super(parent, checkStyle(style)); maximum = 100; increment = 1; pageIncrement = 10; } /** * Adds the listener to the collection of listeners who will be notified when * the user changes the receiver's value, by sending it one of the messages * defined in the <code>SelectionListener</code> interface. * <p> * <code>widgetSelected</code> is called when the user changes the receiver's * value. <code>widgetDefaultSelected</code> is not called. * </p> * * @param listener the listener which should be notified * @exception IllegalArgumentException <ul> * <li>ERROR_NULL_ARGUMENT - if the listener 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> * @see SelectionListener * @see #removeSelectionListener */ public void addSelectionListener(SelectionListener listener) { checkWidget(); if (listener == null) { SWT.error(SWT.ERROR_NULL_ARGUMENT); } TypedListener typedListener = new TypedListener(listener); addListener(SWT.Selection, typedListener); addListener(SWT.DefaultSelection, typedListener); } /** * Removes the listener from the collection of listeners who will be notified * when the user changes the receiver's value. * * @param listener the listener which should no longer be notified * @exception IllegalArgumentException <ul> * <li>ERROR_NULL_ARGUMENT - if the listener 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> * @see SelectionListener * @see #addSelectionListener */ public void removeSelectionListener(SelectionListener listener) { checkWidget(); if (listener == null) { SWT.error(SWT.ERROR_NULL_ARGUMENT); } removeListener(SWT.Selection, listener); removeListener(SWT.DefaultSelection, listener); } @Override public Point computeSize(int wHint, int hHint, boolean changed) { checkWidget(); BoxDimensions border = getBorder(); int width = border.left + border.right; int height = border.top + border.bottom; if ((style & SWT.HORIZONTAL) != 0) { width += PREFERRED_SIZE.x; height += PREFERRED_SIZE.y; } else { width += PREFERRED_SIZE.y; height += PREFERRED_SIZE.x; } if (wHint != SWT.DEFAULT) { width = wHint + border.left + border.right; } if (hHint != SWT.DEFAULT) { height = hHint + border.top + border.bottom; } return new Point(width, height); } /** * Returns the amount that the receiver's value will be modified by when the * up/down (or right/left) arrows are pressed. * * @return the increment * @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 getIncrement() { checkWidget(); return increment; } /** * Returns the maximum value which the receiver will allow. * * @return the maximum * @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 getMaximum() { checkWidget(); return maximum; } /** * Returns the minimum value which the receiver will allow. * * @return the minimum * @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 getMinimum() { checkWidget(); return minimum; } /** * Returns the amount that the receiver's value will be modified by when the * page increment/decrement areas are selected. * * @return the page increment * @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 getPageIncrement() { checkWidget(); return pageIncrement; } /** * Returns the 'selection', which is the receiver's position. * * @return the selection * @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 getSelection() { checkWidget(); return selection; } /** * Sets the amount that the receiver's value will be modified by when the * up/down (or right/left) arrows are pressed to the argument, which must be * at least one. * * @param increment the new increment (must be greater than zero) * @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 setIncrement(int increment) { checkWidget(); if (increment >= 1 && increment <= maximum - minimum) { this.increment = increment; } } /** * Sets the maximum value that the receiver will allow. This new value will be * ignored if it is not greater than the receiver's current minimum value. If * the new maximum is applied then the receiver's selection value will be * adjusted if necessary to fall within its new range. * * @param maximum the new maximum, which must be greater than the current * minimum * @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 setMaximum(int maximum) { checkWidget(); if (0 <= minimum && minimum < maximum) { this.maximum = maximum; if (selection > this.maximum) { selection = this.maximum; } } } /** * Sets the minimum value that the receiver will allow. This new value will be * ignored if it is negative or is not less than the receiver's current * maximum value. If the new minimum is applied then the receiver's selection * value will be adjusted if necessary to fall within its new range. * * @param minimum the new minimum, which must be nonnegative and less than the * current maximum * @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 setMinimum(int minimum) { checkWidget(); if (0 <= minimum && minimum < maximum) { this.minimum = minimum; if (selection < this.minimum) { selection = this.minimum; } } } /** * Sets the amount that the receiver's value will be modified by when the page * increment/decrement areas are selected to the argument, which must be at * least one. * * @param pageIncrement the page increment (must be greater than zero) * @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 setPageIncrement(int pageIncrement) { checkWidget(); if (pageIncrement >= 1 && pageIncrement <= maximum - minimum) { this.pageIncrement = pageIncrement; } } /** * Sets the 'selection', which is the receiver's value, to the argument which * must be greater than or equal to zero. * * @param selection the new selection (must be zero or greater) * @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 setSelection(int selection) { checkWidget(); if (selection >= minimum && selection <= maximum) { this.selection = selection; } } @Override @SuppressWarnings("unchecked") public <T> T getAdapter(Class<T> adapter) { if (adapter == WidgetLCA.class) { return (T) ScaleLCA.INSTANCE; } return super.getAdapter(adapter); } private static int checkStyle(int style) { return checkBits(style, SWT.HORIZONTAL, SWT.VERTICAL, 0, 0, 0, 0); } /////////////////// // Widget overrides @Override boolean isTabGroup() { return true; } }