Java Tutorial/SWT/Sash

Make Split Dragger slim

import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.FormAttachment;
import org.eclipse.swt.layout.FormData;
import org.eclipse.swt.layout.FormLayout;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Sash;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Text;
public class SashSlimDragger {
  public static void main(String[] args) {
    Display display = new Display();
    Shell shell = new Shell(display);
    shell.setText("Sash One");
    shell.setLayout(new FormLayout());
    Sash sash = new Sash(shell, SWT.VERTICAL);
    FormData data = new FormData();
    data.top = new FormAttachment(0, 0); // Attach to top
    data.bottom = new FormAttachment(100, 0); // Attach to bottom
    data.left = new FormAttachment(50, 0); // Attach halfway across
    sash.setLayoutData(data);
    Text one = new Text(shell, SWT.BORDER);
    data = new FormData();
    data.top = new FormAttachment(0, 0);
    data.bottom = new FormAttachment(100, 0);
    data.left = new FormAttachment(0, 0);
    data.right = new FormAttachment(sash, 0);
    one.setLayoutData(data);
    Text two = new Text(shell, SWT.BORDER);
    data = new FormData();
    data.top = new FormAttachment(0, 0);
    data.bottom = new FormAttachment(100, 0);
    data.left = new FormAttachment(sash, 0);
    data.right = new FormAttachment(100, 0);
    two.setLayoutData(data);
    shell.pack();
    shell.open();
    while (!shell.isDisposed()) {
      if (!display.readAndDispatch()) {
        display.sleep();
      }
    }
    display.dispose();
  }
}

Making a Sash Stick

1. The default behavior of the sash allows dragging, but you must write code to make the sash stay.
2. You implement an event handler to adjust the FormAttachment object associated with the sash"s movable direction.
3. For a vertical sash, adjust the left FormAttachment.
4. For a horizontal sash, adjust the top FormAttachment.

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.layout.FormAttachment;
import org.eclipse.swt.layout.FormData;
import org.eclipse.swt.layout.FormLayout;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Sash;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Text;
public class SashFormSticker {
  public static void main(String[] args) {
    Display display = new Display();
    Shell shell = new Shell(display);
    shell.setText("Sash One");
    shell.setLayout(new FormLayout());
    final Sash sash = new Sash(shell, SWT.VERTICAL);
    FormData data = new FormData();
    data.top = new FormAttachment(0, 0); // Attach to top
    data.bottom = new FormAttachment(100, 0); // Attach to bottom
    data.left = new FormAttachment(50, 0); // Attach halfway across
    sash.setLayoutData(data);
    Text one = new Text(shell, SWT.BORDER);
    data = new FormData();
    data.top = new FormAttachment(0, 0);
    data.bottom = new FormAttachment(100, 0);
    data.left = new FormAttachment(0, 0);
    data.right = new FormAttachment(sash, 0);
    one.setLayoutData(data);
    Text two = new Text(shell, SWT.BORDER);
    data = new FormData();
    data.top = new FormAttachment(0, 0);
    data.bottom = new FormAttachment(100, 0);
    data.left = new FormAttachment(sash, 0);
    data.right = new FormAttachment(100, 0);
    two.setLayoutData(data);
    
    sash.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent event) {
        // Reattach to the left edge, and use the x value of the event to
        // determine the offset from the left
        ((FormData) sash.getLayoutData()).left = new FormAttachment(0, event.x);
        // Until the parent window does a layout, the sash will not be redrawn in
        // its new location. So, force a layout.
        sash.getParent().layout();
      }
    });
    
    
    shell.pack();
    shell.open();
    while (!shell.isDisposed()) {
      if (!display.readAndDispatch()) {
        display.sleep();
      }
    }
    display.dispose();
  }
}

Sashes

Sashes, also called splitters

1. Sashes can be horizontal or vertical;
2. The type is determined at construction time, and cannot be changed.
3. The default is vertical.
4. Passing SWT.HORIZONTAL or SWT.VERTICAL to the constructor determines the type:

Sash horizontalSash = new Sash(shell, SWT.HORIZONTAL); // Horizontal sash
Sash verticalSash = new Sash(shell, SWT.VERTICAL); // Vertical sash

Sash: implement a simple splitter (with a 20 pixel limit)

/*******************************************************************************
 * Copyright (c) 2000, 2004 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;
/*
 * Sash example snippet: implement a simple splitter (with a 20 pixel limit)
 *
 * For a list of all SWT example snippets see
 * http://www.eclipse.org/swt/snippets/
 */
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.layout.FormAttachment;
import org.eclipse.swt.layout.FormData;
import org.eclipse.swt.layout.FormLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Sash;
import org.eclipse.swt.widgets.Shell;
public class Splitter20PixelLimit {
  public static void main(String[] args) {
    Display display = new Display();
    final Shell shell = new Shell(display);
    Button button1 = new Button(shell, SWT.PUSH);
    button1.setText("Button 1");
    final Sash sash = new Sash(shell, SWT.VERTICAL);
    Button button2 = new Button(shell, SWT.PUSH);
    button2.setText("Button 2");
    final FormLayout form = new FormLayout();
    shell.setLayout(form);
    FormData button1Data = new FormData();
    button1Data.left = new FormAttachment(0, 0);
    button1Data.right = new FormAttachment(sash, 0);
    button1Data.top = new FormAttachment(0, 0);
    button1Data.bottom = new FormAttachment(100, 0);
    button1.setLayoutData(button1Data);
    final int limit = 20, percent = 50;
    final FormData sashData = new FormData();
    sashData.left = new FormAttachment(percent, 0);
    sashData.top = new FormAttachment(0, 0);
    sashData.bottom = new FormAttachment(100, 0);
    sash.setLayoutData(sashData);
    sash.addListener(SWT.Selection, new Listener() {
      public void handleEvent(Event e) {
        Rectangle sashRect = sash.getBounds();
        Rectangle shellRect = shell.getClientArea();
        int right = shellRect.width - sashRect.width - limit;
        e.x = Math.max(Math.min(e.x, right), limit);
        if (e.x != sashRect.x) {
          sashData.left = new FormAttachment(0, e.x);
          shell.layout();
        }
      }
    });
    FormData button2Data = new FormData();
    button2Data.left = new FormAttachment(sash, 0);
    button2Data.right = new FormAttachment(100, 0);
    button2Data.top = new FormAttachment(0, 0);
    button2Data.bottom = new FormAttachment(100, 0);
    button2.setLayoutData(button2Data);
    shell.pack();
    shell.open();
    while (!shell.isDisposed()) {
      if (!display.readAndDispatch())
        display.sleep();
    }
    display.dispose();
  }
}