Java tutorial
/*==========================================================================*\ | $Id: CancelableBooleanFieldEditor.java,v 1.2 2009/09/13 12:59:29 aallowat Exp $ |*-------------------------------------------------------------------------*| | Copyright (C) 2006-2009 Virginia Tech | | This file is part of Web-CAT Eclipse Plugins. | | Web-CAT is free software; you can redistribute it and/or modify | it under the terms of the GNU General Public License as published by | the Free Software Foundation; either version 2 of the License, or | (at your option) any later version. | | Web-CAT is distributed in the hope that it will be useful, | but WITHOUT ANY WARRANTY; without even the implied warranty of | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | GNU General Public License for more details. | | You should have received a copy of the GNU General Public License | along with Web-CAT; if not, see <http://www.gnu.org/licenses/>. \*==========================================================================*/ package net.sf.webcat.eclipse.cxxtest.preferences; import org.eclipse.jface.preference.FieldEditor; import org.eclipse.swt.SWT; import org.eclipse.swt.events.DisposeEvent; import org.eclipse.swt.events.DisposeListener; import org.eclipse.swt.events.SelectionAdapter; import org.eclipse.swt.events.SelectionEvent; import org.eclipse.swt.layout.GridData; import org.eclipse.swt.widgets.Button; import org.eclipse.swt.widgets.Composite; import org.eclipse.swt.widgets.Control; import org.eclipse.swt.widgets.Label; /** * * @author Tony Allevato (Virginia Tech Computer Science) * @author latest changes by: $Author: aallowat $ * @version $Revision: 1.2 $ $Date: 2009/09/13 12:59:29 $ */ public class CancelableBooleanFieldEditor extends FieldEditor { /** * Style constant (value <code>0</code>) indicating the default layout where * the field editor's check box appears to the left of the label. */ public static final int DEFAULT = 0; /** * Style constant (value <code>1</code>) indicating a layout where the field * editor's label appears on the left with a check box on the right. */ public static final int SEPARATE_LABEL = 1; /** * Style bits. Either <code>DEFAULT</code> or <code>SEPARATE_LABEL</code>. */ private int style; /** * The previously selected, or "before", value. */ private boolean wasSelected; /** * The checkbox control, or <code>null</code> if none. */ private Button checkBox = null; private ICancelableBooleanListener cancelableListener; /** * Creates a new boolean field editor */ protected CancelableBooleanFieldEditor() { } /** * Creates a boolean field editor in the given style. * * @param name * the name of the preference this field editor works on * @param labelText * the label text of the field editor * @param style * the style, either <code>DEFAULT</code> or * <code>SEPARATE_LABEL</code> * @param parent * the parent of the field editor's control * @see #DEFAULT * @see #SEPARATE_LABEL */ public CancelableBooleanFieldEditor(String name, String labelText, int style, Composite parent) { init(name, labelText); this.style = style; createControl(parent); } /** * Creates a boolean field editor in the default style. * * @param name * the name of the preference this field editor works on * @param label * the label text of the field editor * @param parent * the parent of the field editor's control */ public CancelableBooleanFieldEditor(String name, String label, Composite parent) { this(name, label, DEFAULT, parent); } /* * (non-Javadoc) Method declared on FieldEditor. */ protected void adjustForNumColumns(int numColumns) { if (style == SEPARATE_LABEL) { numColumns--; } ((GridData) checkBox.getLayoutData()).horizontalSpan = numColumns; } /* * (non-Javadoc) Method declared on FieldEditor. */ protected void doFillIntoGrid(Composite parent, int numColumns) { String text = getLabelText(); switch (style) { case SEPARATE_LABEL: getLabelControl(parent); numColumns--; text = null; //$FALL-THROUGH$ default: checkBox = getChangeControl(parent); GridData gd = new GridData(); gd.horizontalSpan = numColumns; checkBox.setLayoutData(gd); if (text != null) { checkBox.setText(text); } } } /** * Returns the control responsible for displaying this field editor's label. * This method can be used to set a tooltip for a * <code>BooleanFieldEditor</code>. Note that the normal pattern of * <code>getLabelControl(parent).setToolTipText(tooltipText)</code> does not * work for boolean field editors, as it can lead to duplicate text (see bug * 259952). * * @param parent * the parent composite * @return the control responsible for displaying the label * * @since 3.5 */ public Control getDescriptionControl(Composite parent) { if (style == SEPARATE_LABEL) { return getLabelControl(parent); } return getChangeControl(parent); } public void setCancelableListener(ICancelableBooleanListener listener) { cancelableListener = listener; } /* * (non-Javadoc) Method declared on FieldEditor. Loads the value from the * preference store and sets it to the check box. */ protected void doLoad() { if (checkBox != null) { boolean value = getPreferenceStore().getBoolean(getPreferenceName()); checkBox.setSelection(value); wasSelected = value; } } /* * (non-Javadoc) Method declared on FieldEditor. Loads the default value * from the preference store and sets it to the check box. */ protected void doLoadDefault() { if (checkBox != null) { boolean value = getPreferenceStore().getDefaultBoolean(getPreferenceName()); checkBox.setSelection(value); wasSelected = value; } } /* * (non-Javadoc) Method declared on FieldEditor. */ protected void doStore() { getPreferenceStore().setValue(getPreferenceName(), checkBox.getSelection()); } /** * Returns this field editor's current value. * * @return the value */ public boolean getBooleanValue() { return checkBox.getSelection(); } /** * Returns the change button for this field editor. * * @param parent * The Composite to create the receiver in. * * @return the change button */ protected Button getChangeControl(Composite parent) { if (checkBox == null) { checkBox = new Button(parent, SWT.CHECK | SWT.LEFT); checkBox.setFont(parent.getFont()); checkBox.addSelectionListener(new SelectionAdapter() { public void widgetSelected(SelectionEvent e) { boolean isSelected = checkBox.getSelection(); if (cancelableListener != null) { boolean deny = cancelableListener.shouldDenyChange(isSelected); if (deny) { checkBox.setSelection(!isSelected); return; } } valueChanged(wasSelected, isSelected); wasSelected = isSelected; } }); checkBox.addDisposeListener(new DisposeListener() { public void widgetDisposed(DisposeEvent event) { checkBox = null; } }); } else { checkParent(checkBox, parent); } return checkBox; } /* * (non-Javadoc) Method declared on FieldEditor. */ public int getNumberOfControls() { switch (style) { case SEPARATE_LABEL: return 2; default: return 1; } } /* * (non-Javadoc) Method declared on FieldEditor. */ public void setFocus() { if (checkBox != null) { checkBox.setFocus(); } } /* * (non-Javadoc) Method declared on FieldEditor. */ public void setLabelText(String text) { super.setLabelText(text); Label label = getLabelControl(); if (label == null && checkBox != null) { checkBox.setText(text); } } /** * Informs this field editor's listener, if it has one, about a change to * the value (<code>VALUE</code> property) provided that the old and new * values are different. * * @param oldValue * the old value * @param newValue * the new value */ protected void valueChanged(boolean oldValue, boolean newValue) { setPresentsDefaultValue(false); if (oldValue != newValue) { fireStateChanged(VALUE, oldValue, newValue); } } /* * @see FieldEditor.setEnabled */ public void setEnabled(boolean enabled, Composite parent) { // Only call super if there is a label already if (style == SEPARATE_LABEL) { super.setEnabled(enabled, parent); } getChangeControl(parent).setEnabled(enabled); } }