SelectionButtonDialogFieldGroup.java

/*******************************************************************************
 * Copyright (c) 2008 Pierre-Antoine Grégoire.
 * 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:
 *    Pierre-Antoine Grégoire - initial API and implementation
 *******************************************************************************/
package org.org.eclipse.core.utils.platform.fields;

import org.eclipse.core.runtime.Assert;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.events.SelectionListener;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Group;
import org.eclipse.swt.widgets.Label;

/**
 * Dialog field describing a group with buttons (Checkboxes, radio buttons..) 
 */
public class SelectionButtonDialogFieldGroup extends DialogField {

	private Composite fButtonComposite;

	private Button[] fButtons;

	private String[] fButtonNames;

	private boolean[] fButtonsSelected;

	private boolean[] fButtonsEnabled;

	private int fGroupBorderStyle;

	private int fGroupNumberOfColumns;

	private int fButtonsStyle;

	/**
	 * Creates a group without border.
	 */
	public SelectionButtonDialogFieldGroup(int buttonsStyle, String[] buttonNames, int nColumns) {
		this(buttonsStyle, buttonNames, nColumns, SWT.NONE);
	}

	/**
	 * Creates a group with border (label in border). Accepted button styles are: SWT.RADIO, SWT.CHECK, SWT.TOGGLE For border styles see <code>Group</code>
	 */
	public SelectionButtonDialogFieldGroup(int buttonsStyle, String[] buttonNames, int nColumns, int borderStyle) {

		Assert.isTrue(buttonsStyle == SWT.RADIO || buttonsStyle == SWT.CHECK || buttonsStyle == SWT.TOGGLE);
		fButtonNames = buttonNames;
		fButtonsStyle = buttonsStyle;
		int nButtons = buttonNames.length;
		fButtonsSelected = new boolean[nButtons];
		fButtonsEnabled = new boolean[nButtons];
		for (int i = 0; i < nButtons; i++) {
			fButtonsSelected[i] = false;
			fButtonsEnabled[i] = true;
		}
		if (fButtonsStyle == SWT.RADIO) {
			fButtonsSelected[0] = true;
		}

		fGroupBorderStyle = borderStyle;
		fGroupNumberOfColumns = (nColumns <= 0) ? nButtons : nColumns;

		fButtonsStyle = buttonsStyle;

	}

	// ------- layout helpers

	/*
	 * @see DialogField#doFillIntoGrid
	 */
	public Control[] doFillIntoTable(Composite parent, int nColumns) {

		if (fGroupBorderStyle == SWT.NONE) {
			Label label = getLabelControl(parent);
			label.setLayoutData(gridDataForLabel(1));

			Composite buttonsgroup = getSelectionButtonsGroup(parent);
			GridData td = new GridData();
			td.horizontalSpan = nColumns - 1;
			buttonsgroup.setLayoutData(td);

			return new Control[] { label, buttonsgroup };
		} else {
			Composite buttonsgroup = getSelectionButtonsGroup(parent);
			GridData td = new GridData();
			td.horizontalSpan = nColumns;
			buttonsgroup.setLayoutData(td);

			return new Control[] { buttonsgroup };
		}
	}

	/*
	 * @see DialogField#doFillIntoGrid
	 */
	public int getNumberOfControls() {
		return (fGroupBorderStyle == SWT.NONE) ? 2 : 1;
	}

	// ------- ui creation

	private Button createSelectionButton(int index, Composite group, SelectionListener listener) {
		Button button = new Button(group, fButtonsStyle | SWT.LEFT);
		button.setFont(group.getFont());
		button.setText(fButtonNames[index]);
		button.setEnabled(isEnabled() && fButtonsEnabled[index]);
		button.setSelection(fButtonsSelected[index]);
		button.addSelectionListener(listener);
		button.setLayoutData(new GridData());
		return button;
	}

	/**
	 * Returns the group widget. When called the first time, the widget will be created.
	 * 
	 * @param parent
	 *            The parent composite when called the first time, or <code>null</code> after.
	 */
	public Composite getSelectionButtonsGroup(Composite parent) {
		if (fButtonComposite == null) {
			assertCompositeNotNull(parent);

			GridLayout layout = new GridLayout();
			layout.makeColumnsEqualWidth = true;
			layout.numColumns = fGroupNumberOfColumns;

			if (fGroupBorderStyle != SWT.NONE) {
				Group group = new Group(parent, fGroupBorderStyle);
				if (fLabelText != null && fLabelText.length() > 0) {
					group.setText(fLabelText);
				}
				fButtonComposite = group;
			} else {
				fButtonComposite = new Composite(parent, SWT.NULL);

			}
			fButtonComposite.setLayout(layout);

			SelectionListener listener = new SelectionListener() {
				public void widgetDefaultSelected(SelectionEvent e) {
					doWidgetSelected(e);
				}

				public void widgetSelected(SelectionEvent e) {
					doWidgetSelected(e);
				}
			};
			int nButtons = fButtonNames.length;
			fButtons = new Button[nButtons];
			for (int i = 0; i < nButtons; i++) {
				fButtons[i] = createSelectionButton(i, fButtonComposite, listener);
			}
			int nRows = nButtons / fGroupNumberOfColumns;
			int nFillElements = nRows * fGroupNumberOfColumns - nButtons;
			for (int i = 0; i < nFillElements; i++) {
				createEmptySpace(fButtonComposite);
			}
		}
		return fButtonComposite;
	}

	/**
	 * Returns a button from the group or <code>null</code> if not yet created.
	 */
	public Button getSelectionButton(int index) {
		if (index >= 0 && index < fButtons.length) {
			return fButtons[index];
		}
		return null;
	}

	private void doWidgetSelected(SelectionEvent e) {
		Button button = (Button) e.widget;
		for (int i = 0; i < fButtons.length; i++) {
			if (fButtons[i] == button) {
				fButtonsSelected[i] = button.getSelection();
				dialogFieldChanged();
				return;
			}
		}
	}

	// ------ model access

	/**
	 * Returns the selection state of a button contained in the group.
	 * 
	 * @param index
	 *            The index of the button
	 */
	public boolean isSelected(int index) {
		if (index >= 0 && index < fButtonsSelected.length) {
			return fButtonsSelected[index];
		}
		return false;
	}

	/**
	 * Sets the selection state of a button contained in the group.
	 */
	public void setSelection(int index, boolean selected) {
		if (index >= 0 && index < fButtonsSelected.length) {
			if (fButtonsSelected[index] != selected) {
				fButtonsSelected[index] = selected;
				if (fButtons != null) {
					Button button = fButtons[index];
					if (isOkToUse(button)) {
						button.setSelection(selected);
					}
				}
			}
		}
	}

	// ------ enable / disable management

	protected void updateEnableState() {
		super.updateEnableState();
		if (fButtons != null) {
			boolean enabled = isEnabled();
			for (int i = 0; i < fButtons.length; i++) {
				Button button = fButtons[i];
				if (isOkToUse(button)) {
					button.setEnabled(enabled && fButtonsEnabled[i]);
				}
			}
		}
	}

	/**
	 * Sets the enable state of a button contained in the group.
	 */
	public void enableSelectionButton(int index, boolean enable) {
		if (index >= 0 && index < fButtonsEnabled.length) {
			fButtonsEnabled[index] = enable;
			if (fButtons != null) {
				Button button = fButtons[index];
				if (isOkToUse(button)) {
					button.setEnabled(isEnabled() && enable);
				}
			}
		}
	}

	/**
	 * @see DialogField#refresh()
	 */
	public void refresh() {
		super.refresh();
		for (int i = 0; i < fButtons.length; i++) {
			Button button = fButtons[i];
			if (isOkToUse(button)) {
				button.setSelection(fButtonsSelected[i]);
			}
		}
	}

}