Java tutorial
/****************************************************************************** * Copyright (c) 2000-2016 Ericsson Telecom AB * 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 org.eclipse.titan.designer.preferences.pages; 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. * * @author Kristof Szabados */ public final 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(final String name, final String labelText, final String[][] entryNamesAndValues, final Composite parent) { init(name, labelText); Assert.isTrue(checkArray(entryNamesAndValues)); fEntryNamesAndValues = entryNamesAndValues; createControl(parent); } /** * Checks whether given <code>String[][]</code> is of "type" * <code>String[][2]</code>. * * @param table * the String array-array to check. * @return <code>true</code> if it is OK, and <code>false</code> * otherwise */ private boolean checkArray(final 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; } @Override protected void adjustForNumColumns(final 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; } } @Override protected void doFillIntoGrid(final Composite parent, final 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.END; control.setLayoutData(gd); control.setFont(parent.getFont()); } @Override protected void doLoad() { updateComboForValue(getPreferenceStore().getString(getPreferenceName())); } @Override protected void doLoadDefault() { updateComboForValue(getPreferenceStore().getDefaultString(getPreferenceName())); } @Override protected void doStore() { if (fValue == null) { getPreferenceStore().setToDefault(getPreferenceName()); return; } getPreferenceStore().setValue(getPreferenceName(), fValue); } @Override public int getNumberOfControls() { return 2; } /* * Lazily create and return the Combo control. */ private Combo getComboBoxControl(final 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(final SelectionEvent evt) { String oldValue = fValue; String name = fCombo.getText(); fValue = getValueForName(name); setPresentsDefaultValue(false); fireValueChanged(VALUE, oldValue, fValue); } }); } return fCombo; } /* * Select the name in the combo widget that matches the specified value. */ public void setSelectedValue(final String value) { for (int i = 0; i < fEntryNamesAndValues.length; i++) { if (value.equals(fEntryNamesAndValues[i][1])) { fCombo.setText(fEntryNamesAndValues[i][0]); fValue = value; return; } } } /* * Given the name (label) of an entry, return the corresponding value. */ private String getValueForName(final 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(final 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]); } } /* * Returns the actual value of the combo control */ public String getActualValue() { return fValue; } }