BorderLayout.java Source code

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Here is the source code for BorderLayout.java

Source

/******************************************************************************
 * Copyright (c) 1998, 2004 Jackwind Li Guojie
 * All right reserved. 
 * 
 * Created on Jan 30, 2004 11:52:21 PM by JACK
 * $Id$
 * 
 * visit: http://www.asprise.com/swt
 *****************************************************************************/

import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Layout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Text;

/**
 * Lays out a composite, arranging and resizing its components to fit in five
 * regions: north, south, east, west, and center.
 */
class BorderLayout extends Layout {
    // Region constants.
    public static final int NORTH = 0;
    public static final int SOUTH = 1;
    public static final int CENTER = 2;
    public static final int EAST = 3;
    public static final int WEST = 4;

    /**
     * Indicates the region that a control belongs to.
     *  
     */
    public static class BorderData {
        public int region = CENTER; // default.

        public BorderData() {
        }

        public BorderData(int region) {
            this.region = region;
        }
    }

    // Controls in all the regions.
    public Control[] controls = new Control[5];

    // Cached sizes.
    Point[] sizes;

    // Preferred width and height
    int width;
    int height;

    /*
     * (non-Javadoc)
     * 
     * @see org.eclipse.swt.widgets.Layout#computeSize(org.eclipse.swt.widgets.Composite,
     *      int, int, boolean)
     */
    protected Point computeSize(Composite composite, int wHint, int hHint, boolean flushCache) {

        if (sizes == null || flushCache == true)
            refreshSizes(composite.getChildren());
        int w = wHint;
        int h = hHint;
        if (w == SWT.DEFAULT)
            w = width;
        if (h == SWT.DEFAULT)
            h = height;

        return new Point(w, h);
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.eclipse.swt.widgets.Layout#layout(org.eclipse.swt.widgets.Composite,
     *      boolean)
     */
    protected void layout(Composite composite, boolean flushCache) {
        if (flushCache || sizes == null)
            refreshSizes(composite.getChildren());

        Rectangle clientArea = composite.getClientArea();

        // Enough space for all.
        if (controls[NORTH] != null) {
            controls[NORTH].setBounds(clientArea.x, clientArea.y, clientArea.width, sizes[NORTH].y);
        }
        if (controls[SOUTH] != null) {
            controls[SOUTH].setBounds(clientArea.x, clientArea.y + clientArea.height - sizes[SOUTH].y,
                    clientArea.width, sizes[SOUTH].y);
        }
        if (controls[WEST] != null) {
            controls[WEST].setBounds(clientArea.x, clientArea.y + sizes[NORTH].y, sizes[WEST].x,
                    clientArea.height - sizes[NORTH].y - sizes[SOUTH].y);
        }
        if (controls[EAST] != null) {
            controls[EAST].setBounds(clientArea.x + clientArea.width - sizes[EAST].x, clientArea.y + sizes[NORTH].y,
                    sizes[EAST].x, clientArea.height - sizes[NORTH].y - sizes[SOUTH].y);
        }
        if (controls[CENTER] != null) {
            controls[CENTER].setBounds(clientArea.x + sizes[WEST].x, clientArea.y + sizes[NORTH].y,
                    clientArea.width - sizes[WEST].x - sizes[EAST].x,
                    clientArea.height - sizes[NORTH].y - sizes[SOUTH].y);
        }

    }

    private void refreshSizes(Control[] children) {
        for (int i = 0; i < children.length; i++) {
            Object layoutData = children[i].getLayoutData();
            if (layoutData == null || (!(layoutData instanceof BorderData)))
                continue;
            BorderData borderData = (BorderData) layoutData;
            if (borderData.region < 0 || borderData.region > 4) // Invalid.
                continue;
            controls[borderData.region] = children[i];
        }

        width = 0;
        height = 0;

        if (sizes == null)
            sizes = new Point[5];

        for (int i = 0; i < controls.length; i++) {
            Control control = controls[i];
            if (control == null) {
                sizes[i] = new Point(0, 0);
            } else {
                sizes[i] = control.computeSize(SWT.DEFAULT, SWT.DEFAULT, true);
            }
        }

        width = Math.max(width, sizes[NORTH].x);
        width = Math.max(width, sizes[WEST].x + sizes[CENTER].x + sizes[EAST].x);
        width = Math.max(width, sizes[SOUTH].x);

        height = Math.max(Math.max(sizes[WEST].y, sizes[EAST].y), sizes[CENTER].y) + sizes[NORTH].y
                + sizes[SOUTH].y;

    }

}

/******************************************************************************
 * Copyright (c) 1998, 2004 Jackwind Li Guojie
 * All right reserved. 
 * 
 * Created on Jan 31, 2004 1:05:58 AM by JACK
 * $Id$
 * 
 * visit: http://www.asprise.com/swt
 *****************************************************************************/
public class BorderLayoutSample {
    Display display = new Display();
    Shell shell = new Shell(display);

    public BorderLayoutSample() {
        shell.setLayout(new BorderLayout());

        Button buttonWest = new Button(shell, SWT.PUSH);
        buttonWest.setText("West");
        buttonWest.setLayoutData(new BorderLayout.BorderData(BorderLayout.WEST));

        Button buttonEast = new Button(shell, SWT.PUSH);
        buttonEast.setText("East");
        buttonEast.setLayoutData(new BorderLayout.BorderData(BorderLayout.EAST));

        Button buttonNorth = new Button(shell, SWT.PUSH);
        buttonNorth.setText("North");
        buttonNorth.setLayoutData(new BorderLayout.BorderData(BorderLayout.NORTH));

        Button buttonSouth = new Button(shell, SWT.PUSH);
        buttonSouth.setText("South");
        buttonSouth.setLayoutData(new BorderLayout.BorderData(BorderLayout.SOUTH));

        Text text = new Text(shell, SWT.MULTI | SWT.BORDER | SWT.V_SCROLL | SWT.H_SCROLL);
        text.setText("Center");
        text.setLayoutData(new BorderLayout.BorderData(BorderLayout.CENTER));

        shell.pack();
        shell.open();
        //textUser.forceFocus();

        // Set up the event loop.
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch()) {
                // If no more entries in event queue
                display.sleep();
            }
        }

        display.dispose();
    }

    private void init() {

    }

    public static void main(String[] args) {
        new BorderLayoutSample();
    }
}