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 * Tom Schindl <tom.schindl@bestsolution.at> - bugfix in 174739 *******************************************************************************/ package org.eclipse.jface.viewers; import java.text.MessageFormat; // Not using ICU to support standalone JFace // scenario import org.eclipse.core.runtime.Assert; import org.eclipse.swt.SWT; import org.eclipse.swt.custom.CCombo; import org.eclipse.swt.events.FocusAdapter; import org.eclipse.swt.events.FocusEvent; import org.eclipse.swt.events.KeyAdapter; import org.eclipse.swt.events.KeyEvent; import org.eclipse.swt.events.SelectionAdapter; import org.eclipse.swt.events.SelectionEvent; import org.eclipse.swt.graphics.GC; import org.eclipse.swt.widgets.Composite; import org.eclipse.swt.widgets.Control; /** * A cell editor that presents a list of items in a combo box. The cell editor's * value is the zero-based index of the selected item. * <p> * This class may be instantiated; it is not intended to be subclassed. * </p> * @noextend This class is not intended to be subclassed by clients. */ public class ComboBoxCellEditor extends AbstractComboBoxCellEditor { /** * The list of items to present in the combo box. */ private String[] items; /** * The zero-based index of the selected item. */ int selection; /** * The custom combo box control. */ CCombo comboBox; /** * Default ComboBoxCellEditor style */ private static final int defaultStyle = SWT.NONE; /** * Creates a new cell editor with no control and no st of choices. * Initially, the cell editor has no cell validator. * * @since 2.1 * @see CellEditor#setStyle * @see CellEditor#create * @see ComboBoxCellEditor#setItems * @see CellEditor#dispose */ public ComboBoxCellEditor() { setStyle(defaultStyle); } /** * Creates a new cell editor with a combo containing the given list of * choices and parented under the given control. The cell editor value is * the zero-based index of the selected item. Initially, the cell editor has * no cell validator and the first item in the list is selected. * * @param parent * the parent control * @param items * the list of strings for the combo box */ public ComboBoxCellEditor(Composite parent, String[] items) { this(parent, items, defaultStyle); } /** * Creates a new cell editor with a combo containing the given list of * choices and parented under the given control. The cell editor value is * the zero-based index of the selected item. Initially, the cell editor has * no cell validator and the first item in the list is selected. * * @param parent * the parent control * @param items * the list of strings for the combo box * @param style * the style bits * @since 2.1 */ public ComboBoxCellEditor(Composite parent, String[] items, int style) { super(parent, style); setItems(items); } /** * Returns the list of choices for the combo box * * @return the list of choices for the combo box */ public String[] getItems() { return this.items; } /** * Sets the list of choices for the combo box * * @param items * the list of choices for the combo box */ public void setItems(String[] items) { Assert.isNotNull(items); this.items = items; populateComboBoxItems(); } @Override protected Control createControl(Composite parent) { comboBox = new CCombo(parent, getStyle()); comboBox.setFont(parent.getFont()); populateComboBoxItems(); comboBox.addKeyListener(new KeyAdapter() { // hook key pressed - see PR 14201 @Override public void keyPressed(KeyEvent e) { keyReleaseOccured(e); } }); comboBox.addSelectionListener(new SelectionAdapter() { @Override public void widgetDefaultSelected(SelectionEvent event) { applyEditorValueAndDeactivate(); } @Override public void widgetSelected(SelectionEvent event) { selection = comboBox.getSelectionIndex(); } }); comboBox.addTraverseListener(e -> { if (e.detail == SWT.TRAVERSE_ESCAPE || e.detail == SWT.TRAVERSE_RETURN) { e.doit = false; } }); comboBox.addFocusListener(new FocusAdapter() { @Override public void focusLost(FocusEvent e) { ComboBoxCellEditor.this.focusLost(); } }); return comboBox; } /** * The <code>ComboBoxCellEditor</code> implementation of this * <code>CellEditor</code> framework method returns the zero-based index * of the current selection. * * @return the zero-based index of the current selection wrapped as an * <code>Integer</code> */ @Override protected Object doGetValue() { return Integer.valueOf(selection); } @Override protected void doSetFocus() { comboBox.setFocus(); } /** * The <code>ComboBoxCellEditor</code> implementation of this * <code>CellEditor</code> framework method sets the minimum width of the * cell. The minimum width is 10 characters if <code>comboBox</code> is * not <code>null</code> or <code>disposed</code> else it is 60 pixels * to make sure the arrow button and some text is visible. The list of * CCombo will be wide enough to show its longest item. */ @Override public LayoutData getLayoutData() { LayoutData layoutData = super.getLayoutData(); if ((comboBox == null) || comboBox.isDisposed()) { layoutData.minimumWidth = 60; } else { // make the comboBox 10 characters wide GC gc = new GC(comboBox); layoutData.minimumWidth = (gc.getFontMetrics().getAverageCharWidth() * 10) + 10; gc.dispose(); } return layoutData; } /** * The <code>ComboBoxCellEditor</code> implementation of this * <code>CellEditor</code> framework method accepts a zero-based index of * a selection. * * @param value * the zero-based index of the selection wrapped as an * <code>Integer</code> */ @Override protected void doSetValue(Object value) { Assert.isTrue(comboBox != null && (value instanceof Integer)); selection = ((Integer) value).intValue(); comboBox.select(selection); } /** * Updates the list of choices for the combo box for the current control. */ private void populateComboBoxItems() { if (comboBox != null && items != null) { comboBox.removeAll(); for (int i = 0; i < items.length; i++) { comboBox.add(items[i], i); } setValueValid(true); selection = 0; } } /** * Applies the currently selected value and deactivates the cell editor */ void applyEditorValueAndDeactivate() { // must set the selection before getting value selection = comboBox.getSelectionIndex(); Object newValue = doGetValue(); markDirty(); boolean isValid = isCorrect(newValue); setValueValid(isValid); if (!isValid) { // Only format if the 'index' is valid if (items.length > 0 && selection >= 0 && selection < items.length) { // try to insert the current value into the error message. setErrorMessage(MessageFormat.format(getErrorMessage(), new Object[] { items[selection] })); } else { // Since we don't have a valid index, assume we're using an // 'edit' // combo so format using its text value setErrorMessage(MessageFormat.format(getErrorMessage(), new Object[] { comboBox.getText() })); } } fireApplyEditorValue(); deactivate(); } @Override protected void focusLost() { if (isActivated()) { applyEditorValueAndDeactivate(); } } @Override protected void keyReleaseOccured(KeyEvent keyEvent) { if (keyEvent.character == '\u001b') { // Escape character fireCancelEditor(); } else if (keyEvent.character == '\t') { // tab key applyEditorValueAndDeactivate(); } } }