Java tutorial
/******************************************************************************* * Copyright (c) 2000, 2009 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.globaltester.preferences; import java.io.File; import org.eclipse.jface.preference.DirectoryFieldEditor; import org.eclipse.jface.resource.JFaceResources; import org.eclipse.swt.SWT; import org.eclipse.swt.widgets.Composite; import org.eclipse.swt.widgets.DirectoryDialog; /** * A field editor for a directory path type preference. A standard directory * dialog appears when the user presses the change button. */ public class ValidateDirectoryFieldEditor extends DirectoryFieldEditor { /** * Creates a new directory field editor */ protected ValidateDirectoryFieldEditor() { } /** * Creates a directory field editor. * * @param name the name of the preference this field editor works on * @param labelText the label text of the field editor * @param parent the parent of the field editor's control */ public ValidateDirectoryFieldEditor(String name, String labelText, Composite parent) { init(name, labelText); setErrorMessage(JFaceResources.getString("Use a valid directory!"));//$NON-NLS-1$ setChangeButtonText(JFaceResources.getString("openBrowse"));//$NON-NLS-1$ setValidateStrategy(VALIDATE_ON_KEY_STROKE); createControl(parent); } /* (non-Javadoc) * Method declared on StringButtonFieldEditor. * Opens the directory chooser dialog and returns the selected directory. */ protected String changePressed() { File f = new File(getTextControl().getText()); if (!f.exists()) { f = null; } File d = getDirectory(f); if (d == null) { return null; } return d.getAbsolutePath(); } /* (non-Javadoc) * Method declared on StringFieldEditor. * Checks whether the text input field contains a valid directory. */ protected boolean doCheckState() { String fileName = getTextControl().getText(); Boolean fileIsDirectory; fileName = fileName.trim(); if (fileName.length() == 0 && isEmptyStringAllowed()) { return true; } File file = new File(fileName); fileIsDirectory = file.isDirectory(); return fileIsDirectory; } /** * Helper that opens the directory chooser dialog. * @param startingDirectory The directory the dialog will open in. * @return File File or <code>null</code>. * */ private File getDirectory(File startingDirectory) { DirectoryDialog fileDialog = new DirectoryDialog(getShell(), SWT.OPEN | SWT.SHEET); if (startingDirectory != null) { fileDialog.setFilterPath(startingDirectory.getPath()); } String dir = fileDialog.open(); if (dir != null) { dir = dir.trim(); if (dir.length() > 0) { return new File(dir); } } return null; } }