標(biāo)準(zhǔn)的SWT布局類
FillLayout：在容器中以相同的大小單行或單列的排列組件
RowLayout：以單行或多行的方式使用幾個(gè)選項(xiàng)(fill,wrap,spacing,justify,type)定制組件的排列方式
GridLayout：類似于swing的GridLayout的方式以格子的方式排列組件
FormLayout（SWT 2.0的新特性）：通過定義組件四個(gè)邊的“粘貼”位置來排列組件，被引用的相對(duì)的組件可以父組件，也可以是同一容器中的其它組件。
在SWT中，可以由用戶自定義布局類。
在簡單的布局中，使用FillLayout和RowLayout也許就夠用了，也比較簡單。但是通常的布局都比較復(fù)雜，而且要求很精確。無論復(fù)雜程度如何，都可以由GridLayout或FormLayout來完成。通常GridLayout與FormLayout可以做成同樣的效果，但是使用FormLayout更有效，不會(huì)像GridLayout產(chǎn)生resize導(dǎo)致的布局錯(cuò)位，也更簡單。下面通過一個(gè)例子簡單介紹FormLayout的使用。
布局效果
布局實(shí)施1.首先定義窗口和它的空白邊
Display.getDefault().dispose(); //移去平臺(tái)核心啟動(dòng)畫面
display = new Display();
shell = new Shell(display, SWT.TITLE);
FormLayout layout = new FormLayout();
layout.marginHeight = 10;
layout.marginWidth = 20;
shell.setLayout(layout);
shell.setText("用戶登錄");
2.創(chuàng)建窗口上的元素，其中下面的兩個(gè)button由一個(gè)使用RowLayout的組件來包容。
name = new Label(shell, SWT.NONE);
name.setText("用戶名");
nameText = new Text(shell, SWT.SINGLE | SWT.BORDER);
pass = new Label(shell, SWT.NONE);
pass.setText("密碼");
passText = new Text(shell, SWT.SINGLE | SWT.BORDER);
passText.setEchoChar('*');
passText.setTabs(2);
bottom = new Composite(shell, SWT.NONE);
RowLayout rowLayout = new RowLayout();
rowLayout.justify = true; //justify定義組件在容器中分散開，效果類似于swing的FlowLayout
bottom.setLayout(rowLayout);
3.定義name標(biāo)簽的位置。它的頂邊離父組件（窗口shell）的空白邊距離是父組件clientArea（除空白邊以外的空間）高度(height)的15%，偏移的點(diǎn)數(shù)(points)為0。
FormData data = new FormData();
data.top = new FormAttachment(15, 0);
name.setLayoutData(data);
4.定義name文本輸入的位置。它的頂邊在name標(biāo)簽的中心位置（這不是正確的表達(dá)，但程序是這樣解釋，事實(shí)上它的中心位置與name標(biāo)簽在同一條水平線上），左邊距name標(biāo)簽的右邊有10個(gè)點(diǎn)。
data = new FormData();
data.top = new FormAttachment(name, 0, SWT.CENTER);
data.left = new FormAttachment(name, 10, SWT.RIGHT);
nameText.setLayoutData(data);
5.定義pass標(biāo)簽的位置。它的頂邊距name標(biāo)簽的底邊有10個(gè)點(diǎn)數(shù)的偏移。
data = new FormData();
data.top = new FormAttachment(name, 10, SWT.BOTTOM);
pass.setLayoutData(data);
6.定義pass文本輸入的位置。它的頂邊在name標(biāo)簽的中心位置（同上），左邊與name文本框的左邊對(duì)齊。
data = new FormData();
data.top = new FormAttachment(pass, 0, SWT.CENTER);
data.left = new FormAttachment(nameText, 0, SWT.LEFT);
passText.setLayoutData(data);
7.定義bottom組件的位置。它的頂邊距pass標(biāo)簽的底邊15個(gè)點(diǎn)數(shù)，左邊與pass標(biāo)簽的左邊對(duì)齊，右邊與pass文本輸入的右邊對(duì)齊。
data = new FormData();
data.top = new FormAttachment(pass, 15, SWT.BOTTOM);
data.left = new FormAttachment(pass, 0, SWT.LEFT);
data.right = new FormAttachment(passText, 0, SWT.RIGHT);
bottom.setLayoutData(data);
完整的源碼import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
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.layout.RowLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Text;
import cn.com.efly.clientframe.core.Hook;
/**
* @author efly
* @version 1.0.0,11/22/02
*/
public final class LoginUI {
private Display display;
private Shell shell;
private Composite bottom;
private Label name;
private Label pass;
private Text nameText;
private Text passText;
private Button ok;
private Button exit;
private Rectangle clientArea;
private RootHook rootHook;
public LoginUI(Hook hook) {
rootHook = (RootHook) hook;
}
/**
* 顯示登陸界面
*/
public void show() {
Display.getDefault().dispose();
display = new Display();
clientArea = display.getClientArea();
shell = new Shell(display, SWT.TITLE);
FormLayout layout = new FormLayout();
layout.marginHeight = 10;
layout.marginWidth = 20;
shell.setLayout(layout);
shell.setText("用戶登錄");
name = new Label(shell, SWT.NONE);
name.setText("用戶名");
nameText = new Text(shell, SWT.SINGLE | SWT.BORDER);
pass = new Label(shell, SWT.NONE);
pass.setText("密碼");
passText = new Text(shell, SWT.SINGLE | SWT.BORDER);
passText.setEchoChar('*');
passText.setTabs(2);
bottom = new Composite(shell, SWT.NONE);
RowLayout rowLayout = new RowLayout();
rowLayout.justify = true;
bottom.setLayout(rowLayout);
ok = new Button(bottom, SWT.PUSH);
ok.setText("確定");
ok.addSelectionListener(new SelectionAdapter() {
public void widgetSelected(SelectionEvent event) {
ok();
}
});
exit = new Button(bottom, SWT.PUSH);
exit.setText("取消");
exit.addSelectionListener(new SelectionAdapter() {
public void widgetSelected(SelectionEvent event) {
cancel();
}
});
FormData data = new FormData();
data.top = new FormAttachment(15, 0);
name.setLayoutData(data);
data = new FormData();
data.top = new FormAttachment(name, 0, SWT.CENTER);
data.left = new FormAttachment(name, 10, SWT.RIGHT);
nameText.setLayoutData(data);
data = new FormData();
data.top = new FormAttachment(name, 10, SWT.BOTTOM);
pass.setLayoutData(data);
data = new FormData();
data.top = new FormAttachment(pass, 0, SWT.CENTER);
data.left = new FormAttachment(nameText, 0, SWT.LEFT);
passText.setLayoutData(data);
data = new FormData();
data.top = new FormAttachment(pass, 15, SWT.BOTTOM);
data.left = new FormAttachment(pass, 0, SWT.LEFT);
data.right = new FormAttachment(passText, 0, SWT.RIGHT);
bottom.setLayoutData(data);
shell.pack();
Rectangle shellBounds = shell.getBounds();
shell.setLocation(
(clientArea.width - shellBounds.width) / 2,
(clientArea.height - shellBounds.height) / 2);
shell.open();
while (!shell.isDisposed()) {
if (!display.readAndDispatch())
display.sleep();
}
}
private void dispose() {
display.dispose();
}
private void cancel() {
dispose();
}
private void ok() {
verify();
}
private void verify() {
rootHook.runPlatform();
}
public static void main(String[]){
new LoginUI(null).show();
}
}