Java tutorial
/******************************************************************************* * * * A 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: * * Hitesh Gaur - initial API and implementation *******************************************************************************/ package net.openchrom.xxd.processor.supplier.rscripting.ui.preferences; import org.eclipse.jface.preference.FieldEditor; import org.eclipse.jface.util.Assert; 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. * * This class is copied from Eclipse. */ public class ComboFieldEditor extends FieldEditor { /** * The <code>Combo</code> widget. */ Combo fCombo; /** * The value (not the name) of the currently selected item in the Combo widget. */ 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 field editor * * @param name * @param labelText * @param entryNamesAndValues * @param parent */ public ComboFieldEditor(String name, String labelText, String[][] entryNamesAndValues, Composite parent) { init(name, labelText); Assert.isTrue(checkArray(entryNamesAndValues)); this.fEntryNamesAndValues = entryNamesAndValues; createControl(parent); } /** * Checks whether given <code>String[][]</code> is of "type" * <code>String[][2]</code>. * * @param table * * @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; } /** * @see 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) this.fCombo.getLayoutData()).horizontalSpan = left; } else { Control control = getLabelControl(); if (control != null) { ((GridData) control.getLayoutData()).horizontalSpan = 1; } ((GridData) this.fCombo.getLayoutData()).horizontalSpan = 1; } } /** * @see FieldEditor#doFillIntoGrid(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; gd.grabExcessHorizontalSpace = true; control.setLayoutData(gd); control.setFont(parent.getFont()); } /** * @see FieldEditor#doLoad() */ @Override protected void doLoad() { updateComboForValue(getPreferenceStore().getString(getPreferenceName())); } /** * @see FieldEditor#doLoadDefault() */ @Override protected void doLoadDefault() { updateComboForValue(getPreferenceStore().getDefaultString(getPreferenceName())); } /** * @see FieldEditor#doStore() */ @Override protected void doStore() { if (this.fValue == null) { getPreferenceStore().setToDefault(getPreferenceName()); return; } getPreferenceStore().setValue(getPreferenceName(), this.fValue); } /** * @see FieldEditor#getNumberOfControls() */ @Override public int getNumberOfControls() { return 2; } /** * Lazily create and return the Combo control. * * @param parent * @return Combo */ public Combo getComboBoxControl(Composite parent) { if (this.fCombo == null) { this.fCombo = new Combo(parent, SWT.READ_ONLY); this.fCombo.setFont(parent.getFont()); for (int i = 0; i < this.fEntryNamesAndValues.length; i++) { this.fCombo.add(this.fEntryNamesAndValues[i][0], i); } this.fCombo.addSelectionListener(new SelectionAdapter() { @Override public void widgetSelected(SelectionEvent evt) { String oldValue = ComboFieldEditor.this.fValue; String name = ComboFieldEditor.this.fCombo.getText(); ComboFieldEditor.this.fValue = getValueForName(name); setPresentsDefaultValue(false); fireValueChanged(VALUE, oldValue, ComboFieldEditor.this.fValue); } }); } return this.fCombo; } @Override protected void setPresentsDefaultValue(boolean b) { super.setPresentsDefaultValue(b); } @Override protected void fireValueChanged(String property, Object oldValue, Object newValue) { super.fireValueChanged(property, oldValue, newValue); } /** * Given the name (label) of an entry, return the corresponding value. * * @param name * String * @return String */ protected String getValueForName(String name) { for (int i = 0; i < this.fEntryNamesAndValues.length; i++) { String[] entry = this.fEntryNamesAndValues[i]; if (name.equals(entry[0])) { return entry[1]; } } return this.fEntryNamesAndValues[0][0]; } /** * Set the name in the combo widget to match the specified value. * * @param value */ protected void updateComboForValue(String value) { this.fValue = value; for (int i = 0; i < this.fEntryNamesAndValues.length; i++) { if (value.equals(this.fEntryNamesAndValues[i][1])) { this.fCombo.setText(this.fEntryNamesAndValues[i][0]); return; } } if (this.fEntryNamesAndValues.length > 0) { this.fValue = this.fEntryNamesAndValues[0][1]; } } }