Java tutorial
/******************************************************************************* * Copyright (c) 2000, 2016 IBM Corporation and others. * * This program and the accompanying materials * are made available under the terms of the Eclipse Public License 2.0 * which accompanies this distribution, and is available at * https://www.eclipse.org/legal/epl-2.0/ * * SPDX-License-Identifier: EPL-2.0 * * Contributors: * IBM Corporation - initial API and implementation *******************************************************************************/ package org.eclipse.swt.custom; import org.eclipse.swt.*; import org.eclipse.swt.events.*; import org.eclipse.swt.graphics.*; import org.eclipse.swt.widgets.*; /** * * A TableEditor is a manager for a Control that appears above a cell in a Table and tracks with the * moving and resizing of that cell. It can be used to display a text widget above a cell * in a Table so that the user can edit the contents of that cell. It can also be used to display * a button that can launch a dialog for modifying the contents of the associated cell. * * <p> Here is an example of using a TableEditor:</p> * <pre><code> * final Table table = new Table(shell, SWT.FULL_SELECTION | SWT.HIDE_SELECTION); * TableColumn column1 = new TableColumn(table, SWT.NONE); * TableColumn column2 = new TableColumn(table, SWT.NONE); * for (int i = 0; i < 10; i++) { * TableItem item = new TableItem(table, SWT.NONE); * item.setText(new String[] {"item " + i, "edit this value"}); * } * column1.pack(); * column2.pack(); * * final TableEditor editor = new TableEditor(table); * //The editor must have the same size as the cell and must * //not be any smaller than 50 pixels. * editor.horizontalAlignment = SWT.LEFT; * editor.grabHorizontal = true; * editor.minimumWidth = 50; * // editing the second column * final int EDITABLECOLUMN = 1; * * table.addSelectionListener(new SelectionAdapter() { * public void widgetSelected(SelectionEvent e) { * // Clean up any previous editor control * Control oldEditor = editor.getEditor(); * if (oldEditor != null) oldEditor.dispose(); * * // Identify the selected row * TableItem item = (TableItem)e.item; * if (item == null) return; * * // The control that will be the editor must be a child of the Table * Text newEditor = new Text(table, SWT.NONE); * newEditor.setText(item.getText(EDITABLECOLUMN)); * newEditor.addModifyListener(new ModifyListener() { * public void modifyText(ModifyEvent e) { * Text text = (Text)editor.getEditor(); * editor.getItem().setText(EDITABLECOLUMN, text.getText()); * } * }); * newEditor.selectAll(); * newEditor.setFocus(); * editor.setEditor(newEditor, item, EDITABLECOLUMN); * } * }); * </code></pre> * * @see <a href="http://www.eclipse.org/swt/snippets/#tableeditor">TableEditor snippets</a> * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a> */ public class TableEditor extends ControlEditor { Table table; TableItem item; int column = -1; ControlListener columnListener; Runnable timer; static final int TIMEOUT = 1500; /** * Creates a TableEditor for the specified Table. * * @param table the Table Control above which this editor will be displayed * */ public TableEditor(Table table) { super(table); this.table = table; columnListener = new ControlListener() { @Override public void controlMoved(ControlEvent e) { layout(); } @Override public void controlResized(ControlEvent e) { layout(); } }; timer = () -> layout(); // To be consistent with older versions of SWT, grabVertical defaults to true grabVertical = true; } @Override Rectangle computeBounds() { if (item == null || column == -1 || item.isDisposed()) return new Rectangle(0, 0, 0, 0); Rectangle cell = item.getBounds(column); Rectangle rect = item.getImageBounds(column); if (rect.width != 0) { int imageGap = Math.max(rect.x - cell.x, 0); cell.x = rect.x + rect.width; cell.width -= (imageGap + rect.width); } Rectangle area = table.getClientArea(); if (cell.x < area.x + area.width) { if (cell.x + cell.width > area.x + area.width) { cell.width = area.x + area.width - cell.x; } } Rectangle editorRect = new Rectangle(cell.x, cell.y, minimumWidth, minimumHeight); if (grabHorizontal) { editorRect.width = Math.max(cell.width, minimumWidth); } if (grabVertical) { editorRect.height = Math.max(cell.height, minimumHeight); } if (horizontalAlignment == SWT.RIGHT) { editorRect.x += cell.width - editorRect.width; } else if (horizontalAlignment == SWT.LEFT) { // do nothing - cell.x is the right answer } else { // default is CENTER editorRect.x += (cell.width - editorRect.width) / 2; } if (verticalAlignment == SWT.BOTTOM) { editorRect.y += cell.height - editorRect.height; } else if (verticalAlignment == SWT.TOP) { // do nothing - cell.y is the right answer } else { // default is CENTER editorRect.y += (cell.height - editorRect.height) / 2; } return editorRect; } /** * Removes all associations between the TableEditor and the cell in the table. The * Table and the editor Control are <b>not</b> disposed. */ @Override public void dispose() { if (table != null && !table.isDisposed()) { if (this.column > -1 && this.column < table.getColumnCount()) { TableColumn tableColumn = table.getColumn(this.column); tableColumn.removeControlListener(columnListener); } } columnListener = null; table = null; item = null; column = -1; timer = null; super.dispose(); } /** * Returns the zero based index of the column of the cell being tracked by this editor. * * @return the zero based index of the column of the cell being tracked by this editor */ public int getColumn() { return column; } /** * Returns the TableItem for the row of the cell being tracked by this editor. * * @return the TableItem for the row of the cell being tracked by this editor */ public TableItem getItem() { return item; } void resize() { layout(); /* * On some platforms, the table scrolls when an item that * is partially visible at the bottom of the table is * selected. Ensure that the correct row is edited by * laying out one more time in a timerExec(). */ if (table != null) { Display display = table.getDisplay(); display.timerExec(-1, timer); display.timerExec(TIMEOUT, timer); } } /** * Sets the zero based index of the column of the cell being tracked by this editor. * * @param column the zero based index of the column of the cell being tracked by this editor */ public void setColumn(int column) { int columnCount = table.getColumnCount(); // Separately handle the case where the table has no TableColumns. // In this situation, there is a single default column. if (columnCount == 0) { this.column = (column == 0) ? 0 : -1; resize(); return; } if (this.column > -1 && this.column < columnCount) { TableColumn tableColumn = table.getColumn(this.column); tableColumn.removeControlListener(columnListener); this.column = -1; } if (column < 0 || column >= table.getColumnCount()) return; this.column = column; TableColumn tableColumn = table.getColumn(this.column); tableColumn.addControlListener(columnListener); resize(); } /** * Specifies the <code>TableItem</code> that is to be edited. * * @param item the item to be edited */ public void setItem(TableItem item) { this.item = item; resize(); } @Override public void setEditor(Control editor) { super.setEditor(editor); resize(); } /** * Specify the Control that is to be displayed and the cell in the table that it is to be positioned above. * * <p>Note: The Control provided as the editor <b>must</b> be created with its parent being the Table control * specified in the TableEditor constructor. * * @param editor the Control that is displayed above the cell being edited * @param item the TableItem for the row of the cell being tracked by this editor * @param column the zero based index of the column of the cell being tracked by this editor */ public void setEditor(Control editor, TableItem item, int column) { setItem(item); setColumn(column); setEditor(editor); } @Override public void layout() { if (table == null || table.isDisposed()) return; if (item == null || item.isDisposed()) return; int columnCount = table.getColumnCount(); if (columnCount == 0 && column != 0) return; if (columnCount > 0 && (column < 0 || column >= columnCount)) return; super.layout(); } }