实战SWT布局

雨点打透心脏的1/2处 2022-07-15 07:54 163阅读 0赞

自：http://dolive.javaeye.com/blog/288597

标准的SWT布局类  
FillLayout：在容器中以相同的大小单行或单列的排列组件  
RowLayout：以单行或多行的方式使用几个选项(fill,wrap,spacing,justify,type)定制组件的排列方式  
GridLayout：类似于swing的GridLayout的方式以格子的方式排列组件  
FormLayout（SWT 2.0的新特性）：通过定义组件四个边的“粘贴”位置来排列组件，被引用的相对的组件可以父组件，也可以是同一容器中的其它组件。  
在SWT中，可以由用户自定义布局类。  
  
在简单的布局中，使用FillLayout和RowLayout也许就够用了，也比较简单。但是通常的布局都比较复杂，而且要求很精确。无论复杂 程度如何，都可以由GridLayout或FormLayout来完成。通常GridLayout与FormLayout可以做成同样的效果，但是使用 FormLayout更有效，不会像GridLayout产生resize导致的布局错位，也更简单。下面通过一个例子简单介绍FormLayout的使 用。  
  
布局效果  
  
  
布局实施  
1.首先定义窗口和它的空白边  
Display.getDefault().dispose(); //移去平台核心启动画面  
display = new Display();  
shell = new Shell(display, SWT.TITLE);  
FormLayout layout = new FormLayout();  
layout.marginHeight = 10;  
layout.marginWidth = 20;  
shell.setLayout(layout);  
shell.setText("用户登录");  
  
2.创建窗口上的元素，其中下面的两个button由一个使用RowLayout的组件来包容。  
name = new Label(shell, SWT.NONE);  
name.setText("用户名");  
nameText = new Text(shell, SWT.SINGLE SWT.BORDER);  
pass = new Label(shell, SWT.NONE);  
pass.setText("密码");  
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定义组件在容器中分散开，效果类似于swing的FlowLayout  
bottom.setLayout(rowLayout);  
  
3.定义name标签的位置。它的顶边离父组件（窗口shell）的空白边距离是父组件clientArea（除空白边以外的空间）高度 (height)的15%，偏移的点数(points)为0。  
FormData data = new FormData();  
data.top = new FormAttachment(15, 0);  
name.setLayoutData(data);  
  
4.定义name文本输入的位置。它的顶边在name标签的中心位置（这不是正确的表达，但程序是这样解释，事实上它的中心位置与name标签在 同一条水平线上），左边距name标签的右边有10个点。  
data = new FormData();  
data.top = new FormAttachment(name, 0, SWT.CENTER);  
data.left = new FormAttachment(name, 10, SWT.RIGHT);  
nameText.setLayoutData(data);  
  
5.定义pass标签的位置。它的顶边距name标签的底边有10个点数的偏移。  
data = new FormData();  
data.top = new FormAttachment(name, 10, SWT.BOTTOM);  
pass.setLayoutData(data);  
  
6.定义pass文本输入的位置。它的顶边在name标签的中心位置（同上），左边与name文本框的左边对齐。  
data = new FormData();  
data.top = new FormAttachment(pass, 0, SWT.CENTER);  
data.left = new FormAttachment(nameText, 0, SWT.LEFT);  
passText.setLayoutData(data);  
  
7.定义bottom组件的位置。它的顶边距pass标签的底边15个点数，左边与pass标签的左边对齐，右边与pass文本输入的右边对齐。  
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);  
  
完整的源码  
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;  
\}  
  
/\*\*  
\* 显示登陆界面  
\*/  
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("用户登录");  
  
name = new Label(shell, SWT.NONE);  
name.setText("用户名");  
nameText = new Text(shell, SWT.SINGLE SWT.BORDER);  
pass = new Label(shell, SWT.NONE);  
pass.setText("密码");  
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("确定");  
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();  
\}  
\}