com.mulgasoft.emacsplus.preferences.ButtonFieldEditor.java Source code

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Here is the source code for com.mulgasoft.emacsplus.preferences.ButtonFieldEditor.java

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/**
 * Copyright (c) 2009, 2010 Mark Feber, MulgaSoft
 *
 * 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
 */
package com.mulgasoft.emacsplus.preferences;

import org.eclipse.jface.dialogs.IDialogConstants;
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.layout.GridData;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;

/**
 * A stand-alone button for inclusion in a preference page
 * 
 * @author Mark Feber - initial API and implementation
 */
public class ButtonFieldEditor extends FieldEditor {

    Composite top = null;
    private Button button;

    /**
     * Construct a stand-alone button for inclusion in the preference page
     *  
     * @param parent the composite parent
     * @param buttonText displayed by the button
     * @param onPush the button behavior on push: a SelectionAdapter
     * new SelectionAdapter() {
     *     public void widgetSelected(SelectionEvent evt) {
     *        // button behavior
     *     }
     * }
     */
    public ButtonFieldEditor(Composite parent, String buttonText, SelectionAdapter onPush) {
        super("noop", buttonText, parent); //$NON-NLS-1$
        button.addSelectionListener(onPush);
    }

    protected Button getButtonControl(Composite parent) {
        if (button == null) {
            button = new Button(parent, SWT.PUSH);
            button.setText(getLabelText());
            button.setFont(parent.getFont());
            button.addDisposeListener(new DisposeListener() {
                public void widgetDisposed(DisposeEvent event) {
                    button = null;
                }
            });
        } else {
            checkParent(button, parent);
        }
        return button;
    }

    public void setEnabled(boolean enabled, Composite parent) {
        getButtonControl(parent).setEnabled(enabled);
    }

    /**
    * @see org.eclipse.jface.preference.FieldEditor#adjustForNumColumns(int)
    */
    @Override
    protected void adjustForNumColumns(int numColumns) {
        ((GridData) top.getLayoutData()).horizontalSpan = numColumns;
    }

    /**
     * @see org.eclipse.jface.preference.FieldEditor#doFillIntoGrid(org.eclipse.swt.widgets.Composite, int)
     */
    @Override
    protected void doFillIntoGrid(Composite parent, int numColumns) {
        top = parent;
        GridData gd = new GridData();
        gd.horizontalSpan = numColumns;
        gd.horizontalAlignment = GridData.FILL;
        gd.horizontalAlignment = GridData.END;
        gd.grabExcessHorizontalSpace = true;

        button = getButtonControl(parent);

        int widthHint = convertHorizontalDLUsToPixels(button, IDialogConstants.BUTTON_WIDTH);
        gd.widthHint = Math.max(widthHint, button.computeSize(SWT.DEFAULT, SWT.DEFAULT, true).x);
        button.setLayoutData(gd);
    }

    /**
     * @see org.eclipse.jface.preference.FieldEditor#doLoad()
     */
    @Override
    protected void doLoad() {
        // nope
    }

    /**
     * @see org.eclipse.jface.preference.FieldEditor#doLoadDefault()
     */
    @Override
    protected void doLoadDefault() {
        // nope
    }

    /**
     * @see org.eclipse.jface.preference.FieldEditor#doStore()
     */
    @Override
    protected void doStore() {
        // nope
    }

    /**
     * @see org.eclipse.jface.preference.FieldEditor#getNumberOfControls()
     */
    @Override
    public int getNumberOfControls() {
        return 1;
    }

}