Java tutorial
/******************************************************************************* * Copyright (c) 2000, 2015 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 * Baltasar Belyavsky - fix for 300539 - Add ability to specify filter-path *******************************************************************************/ package org.eclipse.jface.preference; import java.io.File; import org.eclipse.jface.resource.JFaceResources; import org.eclipse.swt.SWT; import org.eclipse.swt.widgets.Composite; import org.eclipse.swt.widgets.FileDialog; /** * A field editor for a file path type preference. A standard file * dialog appears when the user presses the change button. */ public class FileFieldEditor extends StringButtonFieldEditor { /** * List of legal file extension suffixes, or <code>null</code> * for system defaults. */ private String[] extensions = null; /** * Initial path for the Browse dialog. */ private File filterPath = null; /** * Indicates whether the path must be absolute; * <code>false</code> by default. */ private boolean enforceAbsolute = false; /** * Creates a new file field editor */ protected FileFieldEditor() { } /** * Creates a file 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 FileFieldEditor(String name, String labelText, Composite parent) { this(name, labelText, false, parent); } /** * Creates a file field editor. * * @param name the name of the preference this field editor works on * @param labelText the label text of the field editor * @param enforceAbsolute <code>true</code> if the file path * must be absolute, and <code>false</code> otherwise * @param parent the parent of the field editor's control */ public FileFieldEditor(String name, String labelText, boolean enforceAbsolute, Composite parent) { this(name, labelText, enforceAbsolute, VALIDATE_ON_FOCUS_LOST, parent); } /** * Creates a file field editor. * * @param name the name of the preference this field editor works on * @param labelText the label text of the field editor * @param enforceAbsolute <code>true</code> if the file path * must be absolute, and <code>false</code> otherwise * @param validationStrategy either {@link StringButtonFieldEditor#VALIDATE_ON_KEY_STROKE} * to perform on the fly checking, or {@link StringButtonFieldEditor#VALIDATE_ON_FOCUS_LOST} * (the default) to perform validation only after the text has been typed in * @param parent the parent of the field editor's control. * @since 3.4 * @see StringButtonFieldEditor#VALIDATE_ON_KEY_STROKE * @see StringButtonFieldEditor#VALIDATE_ON_FOCUS_LOST */ public FileFieldEditor(String name, String labelText, boolean enforceAbsolute, int validationStrategy, Composite parent) { init(name, labelText); this.enforceAbsolute = enforceAbsolute; setErrorMessage(JFaceResources.getString("FileFieldEditor.errorMessage"));//$NON-NLS-1$ setChangeButtonText(JFaceResources.getString("openBrowse"));//$NON-NLS-1$ setValidateStrategy(validationStrategy); createControl(parent); } @Override protected String changePressed() { File f = new File(getTextControl().getText()); if (!f.exists()) { f = null; } File d = getFile(f); if (d == null) { return null; } return d.getAbsolutePath(); } @Override protected boolean checkState() { String msg = null; String path = getTextControl().getText(); if (path != null) { path = path.trim(); } else { path = "";//$NON-NLS-1$ } if (path.length() == 0) { if (!isEmptyStringAllowed()) { msg = getErrorMessage(); } } else { File file = new File(path); if (file.isFile()) { if (enforceAbsolute && !file.isAbsolute()) { msg = JFaceResources.getString("FileFieldEditor.errorMessage2");//$NON-NLS-1$ } } else { msg = getErrorMessage(); } } if (msg != null) { // error showErrorMessage(msg); return false; } if (doCheckState()) { // OK! clearErrorMessage(); return true; } msg = getErrorMessage(); // subclass might have changed it in the #doCheckState() if (msg != null) { showErrorMessage(msg); } return false; } /** * Helper to open the file chooser dialog. * @param startingDirectory the directory to open the dialog on. * @return File The File the user selected or <code>null</code> if they * do not. */ private File getFile(File startingDirectory) { FileDialog dialog = new FileDialog(getShell(), SWT.OPEN | SWT.SHEET); if (startingDirectory != null) { dialog.setFileName(startingDirectory.getPath()); } else if (filterPath != null) { dialog.setFilterPath(filterPath.getPath()); } if (extensions != null) { dialog.setFilterExtensions(extensions); } String file = dialog.open(); if (file != null) { file = file.trim(); if (file.length() > 0) { return new File(file); } } return null; } /** * Sets this file field editor's file extension filter. * * @param extensions a list of file extension, or <code>null</code> * to set the filter to the system's default value */ public void setFileExtensions(String[] extensions) { this.extensions = extensions; } /** * Sets the initial path for the Browse dialog. * @param path initial path for the Browse dialog * @since 3.6 */ public void setFilterPath(File path) { filterPath = path; } }