A BorderLayout
//Send questions, comments, bug reports, etc. to the authors:
//Rob Warner (rwarner@interspatial.com)
//Robert Harris (rbrt_harris@yahoo.com)
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.*;
/**
* This class contains a BorderLayout, which is loosely patterned after the old
* AWT BorderLayout. It uses the <code>BorderData</code> class to determine
* positioning of controls. To position controls, call <code>control.setLayoutData()</code>,
* passing the <code>BorderData</code> of your choice.
*
* For example:
*
* <code>
* shell.setLayoutData(new BorderLayout());
* Button button = new Button(shell, SWT.PUSH);
* button.setLayoutData(BorderData.NORTH);
* </code>
*
* Note that you can add as many controls to the same direction as you like, but
* the last one added for the direction will be the one displayed.
*/
class YetAnotherBorderLayout extends Layout {
private Control north;
private Control south;
private Control east;
private Control west;
private Control center;
/**
* Computes the size for this BorderLayout.
*
* @param composite the composite that contains the controls
* @param wHint width hint in pixels for the minimum width
* @param hHint height hint in pixels for the minimum height
* @param flushCache if true, flushes any cached values
* @return Point
* @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) {
getControls(composite);
int width = 0, height = 0;
// The width is the width of the west control
// plus the width of the center control
// plus the width of the east control.
// If this is less than the width of the north
// or the south control, however, use the largest
// of those three widths.
width += west == null ? 0 : getSize(west, flushCache).x;
width += east == null ? 0 : getSize(east, flushCache).x;
width += center == null ? 0 : getSize(center, flushCache).x;
if (north != null) {
Point pt = getSize(north, flushCache);
width = Math.max(width, pt.x);
}
if (south != null) {
Point pt = getSize(south, flushCache);
width = Math.max(width, pt.x);
}
// The height is the height of the north control
// plus the height of the maximum height of the
// west, center, and east controls
// plus the height of the south control.
height += north == null ? 0 : getSize(north, flushCache).y;
height += south == null ? 0 : getSize(south, flushCache).y;
int heightOther = center == null ? 0 : getSize(center, flushCache).y;
if (west != null) {
Point pt = getSize(west, flushCache);
heightOther = Math.max(heightOther, pt.y);
}
if (east != null) {
Point pt = getSize(east, flushCache);
heightOther = Math.max(heightOther, pt.y);
}
height += heightOther;
// Respect the wHint and hHint
return new Point(Math.max(width, wHint), Math.max(height, hHint));
}
/**
* This does the work of laying out our controls.
*
* @see org.eclipse.swt.widgets.Layout#layout(org.eclipse.swt.widgets.Composite,
* boolean)
*/
protected void layout(Composite composite, boolean flushCache) {
getControls(composite);
Rectangle rect = composite.getClientArea();
int left = rect.x, right = rect.width, top = rect.y, bottom = rect.height;
if (north != null) {
Point pt = getSize(north, flushCache);
north.setBounds(left, top, rect.width, pt.y);
top += pt.y;
}
if (south != null) {
Point pt = getSize(south, flushCache);
south.setBounds(left, rect.height - pt.y, rect.width, pt.y);
bottom -= pt.y;
}
if (east != null) {
Point pt = getSize(east, flushCache);
east.setBounds(rect.width - pt.x, top, pt.x, (bottom - top));
right -= pt.x;
}
if (west != null) {
Point pt = getSize(west, flushCache);
west.setBounds(left, top, pt.x, (bottom - top));
left += pt.x;
}
if (center != null) {
center.setBounds(left, top, (right - left), (bottom - top));
}
}
protected Point getSize(Control control, boolean flushCache) {
return control.computeSize(SWT.DEFAULT, SWT.DEFAULT, flushCache);
}
protected void getControls(Composite composite) {
// Iterate through all the controls, setting
// the member data according to the BorderData.
// Note that we overwrite any previously set data.
// Note also that we default to CENTER
Control[] children = composite.getChildren();
for (int i = 0, n = children.length; i < n; i++) {
Control child = children[i];
BorderData borderData = (BorderData) child.getLayoutData();
if (borderData == BorderData.NORTH)
north = child;
else if (borderData == BorderData.SOUTH)
south = child;
else if (borderData == BorderData.EAST)
east = child;
else if (borderData == BorderData.WEST)
west = child;
else
center = child;
}
}
}
//Send questions, comments, bug reports, etc. to the authors:
//Rob Warner (rwarner@interspatial.com)
//Robert Harris (rbrt_harris@yahoo.com)
public class BorderLayoutTest {
public static void main(String[] args) {
Display display = new Display();
final Shell shell = new Shell(display);
shell.setLayout(new YetAnotherBorderLayout());
Button b1 = new Button(shell, SWT.PUSH);
b1.setText("North");
b1.setLayoutData(BorderData.NORTH);
Button b2 = new Button(shell, SWT.PUSH);
b2.setText("South");
b2.setLayoutData(BorderData.SOUTH);
Button b3 = new Button(shell, SWT.PUSH);
b3.setText("East");
b3.setLayoutData(BorderData.EAST);
Button b4 = new Button(shell, SWT.PUSH);
b4.setText("West");
b4.setLayoutData(BorderData.WEST);
Button b5 = new Button(shell, SWT.PUSH);
b5.setText("Center");
b5.setLayoutData(BorderData.CENTER);
shell.pack();
shell.open();
while (!shell.isDisposed()) {
if (!display.readAndDispatch()) {
display.sleep();
}
}
display.dispose();
}
}
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