Java tutorial
/* * Yeti 2, NesC development in Eclipse. * Copyright (C) 2009 ETH Zurich * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. * * Web: http://tos-ide.ethz.ch * Mail: tos-ide@tik.ee.ethz.ch */ package tinyos.yeti.environment.basic.preferences.widgets; /******************************************************************************* * 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 *******************************************************************************/ import org.eclipse.core.runtime.Assert; import org.eclipse.jface.preference.FieldEditor; import org.eclipse.swt.SWT; import org.eclipse.swt.events.SelectionAdapter; import org.eclipse.swt.events.SelectionEvent; import org.eclipse.swt.layout.GridData; import org.eclipse.swt.widgets.Combo; import org.eclipse.swt.widgets.Composite; import org.eclipse.swt.widgets.Control; /** * A field editor for a combo box that allows the drop-down selection of one of * a list of items.<br> * This editor is a copy of {@link org.eclipse.jface.preference.ComboFieldEditor}, * new valuable methods, like query the current value, have been added. * @since 3.3 */ public class ComboFieldEditor extends FieldEditor { /** * The <code>Combo</code> widget. */ private Combo fCombo; /** * The value (not the name) of the currently selected item in the Combo widget. */ private String fValue; /** * The names (labels) and underlying values to populate the combo widget. These should be * arranged as: { {name1, value1}, {name2, value2}, ...} */ private String[][] fEntryNamesAndValues; /** * Create the combo box field editor. * * @param name the name of the preference this field editor works on * @param labelText the label text of the field editor * @param entryNamesAndValues the names (labels) and underlying values to populate the combo widget. These should be * arranged as: { {name1, value1}, {name2, value2}, ...} * @param parent the parent composite */ public ComboFieldEditor(String name, String labelText, String[][] entryNamesAndValues, Composite parent) { init(name, labelText); Assert.isTrue(checkArray(entryNamesAndValues)); fEntryNamesAndValues = entryNamesAndValues; createControl(parent); } /** * Gets the current selection of this field editor, this method works only * if the editor is shown. * @return the current selection */ public String getSelection() { return getValueForName(fCombo.getText()); } /** * Checks whether given <code>String[][]</code> is of "type" * <code>String[][2]</code>. * * @return <code>true</code> if it is ok, and <code>false</code> otherwise */ private boolean checkArray(String[][] table) { if (table == null) { return false; } for (int i = 0; i < table.length; i++) { String[] array = table[i]; if (array == null || array.length != 2) { return false; } } return true; } /* (non-Javadoc) * @see org.eclipse.jface.preference.FieldEditor#adjustForNumColumns(int) */ @Override protected void adjustForNumColumns(int numColumns) { if (numColumns > 1) { Control control = getLabelControl(); int left = numColumns; if (control != null) { ((GridData) control.getLayoutData()).horizontalSpan = 1; left = left - 1; } ((GridData) fCombo.getLayoutData()).horizontalSpan = left; } else { Control control = getLabelControl(); if (control != null) { ((GridData) control.getLayoutData()).horizontalSpan = 1; } ((GridData) fCombo.getLayoutData()).horizontalSpan = 1; } } /* (non-Javadoc) * @see org.eclipse.jface.preference.FieldEditor#doFillIntoGrid(org.eclipse.swt.widgets.Composite, int) */ @Override protected void doFillIntoGrid(Composite parent, int numColumns) { int comboC = 1; if (numColumns > 1) { comboC = numColumns - 1; } Control control = getLabelControl(parent); GridData gd = new GridData(); gd.horizontalSpan = 1; control.setLayoutData(gd); control = getComboBoxControl(parent); gd = new GridData(); gd.horizontalSpan = comboC; gd.horizontalAlignment = GridData.FILL; control.setLayoutData(gd); control.setFont(parent.getFont()); } /* (non-Javadoc) * @see org.eclipse.jface.preference.FieldEditor#doLoad() */ @Override protected void doLoad() { updateComboForValue(getPreferenceStore().getString(getPreferenceName())); } /* (non-Javadoc) * @see org.eclipse.jface.preference.FieldEditor#doLoadDefault() */ @Override protected void doLoadDefault() { updateComboForValue(getPreferenceStore().getDefaultString(getPreferenceName())); } /* (non-Javadoc) * @see org.eclipse.jface.preference.FieldEditor#doStore() */ @Override protected void doStore() { if (fValue == null) { getPreferenceStore().setToDefault(getPreferenceName()); return; } getPreferenceStore().setValue(getPreferenceName(), fValue); } /* (non-Javadoc) * @see org.eclipse.jface.preference.FieldEditor#getNumberOfControls() */ @Override public int getNumberOfControls() { return 2; } /* * Lazily create and return the Combo control. */ public Combo getComboBoxControl(Composite parent) { if (fCombo == null) { fCombo = new Combo(parent, SWT.READ_ONLY); fCombo.setFont(parent.getFont()); for (int i = 0; i < fEntryNamesAndValues.length; i++) { fCombo.add(fEntryNamesAndValues[i][0], i); } fCombo.addSelectionListener(new SelectionAdapter() { @Override public void widgetSelected(SelectionEvent evt) { String oldValue = fValue; String name = fCombo.getText(); fValue = getValueForName(name); setPresentsDefaultValue(false); fireValueChanged(VALUE, oldValue, fValue); } }); } return fCombo; } /* * Given the name (label) of an entry, return the corresponding value. */ private String getValueForName(String name) { for (int i = 0; i < fEntryNamesAndValues.length; i++) { String[] entry = fEntryNamesAndValues[i]; if (name.equals(entry[0])) { return entry[1]; } } return fEntryNamesAndValues[0][0]; } /* * Set the name in the combo widget to match the specified value. */ private void updateComboForValue(String value) { fValue = value; for (int i = 0; i < fEntryNamesAndValues.length; i++) { if (value.equals(fEntryNamesAndValues[i][1])) { fCombo.setText(fEntryNamesAndValues[i][0]); return; } } if (fEntryNamesAndValues.length > 0) { fValue = fEntryNamesAndValues[0][1]; fCombo.setText(fEntryNamesAndValues[0][0]); } } }