org.eclipse.swt.custom.TableEditor.java Source code

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/*******************************************************************************
 * 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 &lt; 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();
    }
}