Table events: MeasureItem, PaintItem and EraseItem : Table Event « SWT « Java Tutorial






Table events: MeasureItem, PaintItem and EraseItem
/*******************************************************************************
 * Copyright (c) 2000, 2006 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
 *******************************************************************************/
//package org.eclipse.swt.snippets;
/* 
 * example snippet: Multiple lines per TableItem
 *
 * For a list of all SWT example snippets see
 * http://www.eclipse.org/swt/snippets/
 * 
 * @since 3.2
 */

import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Table;
import org.eclipse.swt.widgets.TableColumn;
import org.eclipse.swt.widgets.TableItem;

public class TableEventMeasureItemPaintItemEraseItem {

  public static void main(String[] args) {
    Display display = new Display();
    Shell shell = new Shell(display);
    shell.setText("Multiple lines in a TableItem");
    shell.setLayout(new FillLayout());
    final Table table = new Table(shell, SWT.MULTI | SWT.FULL_SELECTION);
    table.setHeaderVisible(true);
    table.setLinesVisible(true);
    int columnCount = 4;
    for (int i = 0; i < columnCount; i++) {
      TableColumn column = new TableColumn(table, SWT.NONE);
      column.setText("Column " + i);
    }
    int itemCount = 8;
    for (int i = 0; i < itemCount; i++) {
      TableItem item = new TableItem(table, SWT.NONE);
      item.setText(new String[] { "item " + i + " a", "item " + i + " b", "item " + i + " c",
          "item " + i + " d" });
    }
    /*
     * NOTE: MeasureItem, PaintItem and EraseItem are called repeatedly.
     * Therefore, it is critical for performance that these methods be as
     * efficient as possible.
     */
    Listener paintListener = new Listener() {
      public void handleEvent(Event event) {
        switch (event.type) {
        case SWT.MeasureItem: {
          TableItem item = (TableItem) event.item;
          String text = getText(item, event.index);
          Point size = event.gc.textExtent(text);
          event.width = size.x;
          event.height = Math.max(event.height, size.y);
          break;
        }
        case SWT.PaintItem: {
          TableItem item = (TableItem) event.item;
          String text = getText(item, event.index);
          Point size = event.gc.textExtent(text);
          int offset2 = event.index == 0 ? Math.max(0, (event.height - size.y) / 2) : 0;
          event.gc.drawText(text, event.x, event.y + offset2, true);
          break;
        }
        case SWT.EraseItem: {
          event.detail &= ~SWT.FOREGROUND;
          break;
        }
        }
      }

      String getText(TableItem item, int column) {
        String text = item.getText(column);
        if (column != 0) {
          int index = table.indexOf(item);
          if ((index + column) % 3 == 1) {
            text += "\nnew line";
          }
          if ((index + column) % 3 == 2) {
            text += "\nnew line\nnew line";
          }
        }
        return text;
      }
    };
    table.addListener(SWT.MeasureItem, paintListener);
    table.addListener(SWT.PaintItem, paintListener);
    table.addListener(SWT.EraseItem, paintListener);
    for (int i = 0; i < columnCount; i++) {
      table.getColumn(i).pack();
    }
    shell.pack();
    shell.open();
    while (!shell.isDisposed()) {
      if (!display.readAndDispatch())
        display.sleep();
    }
    display.dispose();
  }
}








17.52.Table Event
17.52.1.Table SetData EventTable SetData Event
17.52.2.Add Table Selection Listener and Get Selected TableItemAdd Table Selection Listener and Get Selected TableItem
17.52.3.Add Default Table Selection Listener and Get the Selected TableItemAdd Default Table Selection Listener and Get the Selected TableItem
17.52.4.Table measure item listenerTable measure item listener
17.52.5.Table events: MeasureItem, PaintItem and EraseItemTable events: MeasureItem, PaintItem and EraseItem
17.52.6.Table paint item listenerTable paint item listener
17.52.7.TableColumn Move ListenerTableColumn Move Listener
17.52.8.Find a table cell from mouse down (works for any table style)Find a table cell from mouse down (works for any table style)
17.52.9.Get TableItem from Mouse positionGet TableItem from Mouse position
17.52.10.Table Selection EventTable Selection Event
17.52.11.Make a dropped data type depend on a target item in tableMake a dropped data type depend on a target item in table