/*******************************************************************************
* Copyright (c) 2000, 2006 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.jface.preference;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.*;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.widgets.*;
/**
* A field editor for a boolean type preference.
*/
public class BooleanFieldEditor 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;
/**
* Creates a new boolean field editor
*/
protected BooleanFieldEditor() {
}
/**
* 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 BooleanFieldEditor(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 BooleanFieldEditor(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;
default:
checkBox = getChangeControl(parent);
GridData gd = new GridData();
gd.horizontalSpan = numColumns;
checkBox.setLayoutData(gd);
if (text != null) {
checkBox.setText(text);
}
}
}
/* (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();
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);
}
}