SWT(JFace)体验之FormLayout规划

测试代码如下：
package swt_jface.demo2;
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.Button;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
public class FormLayoutSample {
Display display = new Display();
Shell shell = new Shell(display);
public FormLayoutSample() {
shell.setLayout(new FormLayout());
Button button1 = new Button(shell, SWT.PUSH);
button1.setText("button1");
FormData formData = new FormData();
formData.left = new FormAttachment(20);
formData.top = new FormAttachment(20);
button1.setLayoutData(formData);

Button button2 = new Button(shell, SWT.PUSH);
button2.setText("button number 2");

formData = new FormData();
formData.left = new FormAttachment(button1, 0, SWT.CENTER);
formData.top = new FormAttachment(button1, 0, SWT.CENTER);
button2.setLayoutData(formData);

// Button button3 = new Button(shell, SWT.PUSH);
// button3.setText("3");
//
// formData = new FormData();
// formData.top = new FormAttachment(button2, 10);
// formData.left = new FormAttachment(button2, 0, SWT.LEFT);
// button3.setLayoutData(formData);
shell.pack();
//shell.setSize(500, 600);
shell.open();
while (!shell.isDisposed()) {
if (!display.readAndDispatch()) {
display.sleep();
}
}
display.dispose();
}
public static void main(String[] args) {
new FormLayoutSample();
}
}

再看一个例子：
package swt_jface.demo2;
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Point;
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.Label;
import org.eclipse.swt.widgets.List;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Shell;
public class Main {
public static void main(String[] args) {
Display display = new Display();
final Shell shell = new Shell(display);
Label label = new Label(shell, SWT.WRAP);
label
.setText("This is a long text string that will wrap when the dialog is resized.");
List list = new List(shell, SWT.BORDER | SWT.H_SCROLL | SWT.V_SCROLL);
list.setItems(new String[] { "Item 1", "Item2" });
Button button1 = new Button(shell, SWT.PUSH);
button1.setText("Ok");
Button button2 = new Button(shell, SWT.PUSH);
button2.setText("Cancel");
final int insetX = 4, insetY = 4;
FormLayout formLayout = new FormLayout();
formLayout.marginWidth = insetX;
formLayout.marginHeight = insetY;
shell.setLayout(formLayout);
Point size = label.computeSize(SWT.DEFAULT, SWT.DEFAULT);
final FormData labelData = new FormData(size.x, SWT.DEFAULT);
labelData.left = new FormAttachment(0, 0);
labelData.right = new FormAttachment(100, 0);
label.setLayoutData(labelData);
shell.addListener(SWT.Resize, new Listener() {
public void handleEvent(Event e) {
Rectangle rect = shell.getClientArea();
labelData.width = rect.width - insetX * 2;
shell.layout();
}
});
FormData button2Data = new FormData();
button2Data.right = new FormAttachment(100, -insetX);
button2Data.bottom = new FormAttachment(100, 0);
button2.setLayoutData(button2Data);
FormData button1Data = new FormData();
button1Data.right = new FormAttachment(button2, -insetX);
button1Data.bottom = new FormAttachment(100, 0);
button1.setLayoutData(button1Data);
FormData listData = new FormData();
listData.left = new FormAttachment(0, 0);
listData.right = new FormAttachment(100, 0);
listData.top = new FormAttachment(label, insetY);
listData.bottom = new FormAttachment(button2, -insetY);
list.setLayoutData(listData);
shell.pack();
shell.open();
while (!shell.isDisposed()) {
if (!display.readAndDispatch())
display.sleep();
}
display.dispose();
}
}