Eclipse插件开发系列5.SWT中的布局管理器(3)

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*************************************************************************************作者：陈刚，桂林人，97年毕业于广西师范大学数学系，专注于java平台。现(2004.2-?)暂在IBM中国研究中心进行Eclipse插件的开发。Email: glchengang@163.comblog:　glchengang.yeah.net*************************************************************************************

　StackLayout称做堆栈式布局，所谓堆栈式就象一付叠在一起的扑克牌，一叠UI面板只显示位于最上面的那个面板。如下图，是Eclipse中比较典型的用到堆栈式布局的界面(打开方法：主菜单窗口-->首选项)。右边部分就是一个堆栈式的布局，当左边选不同的项，右边就显示这一项相应的面板。

StackLayout布局的使用是比较简单的。下面我们来写一个用StackLayout的例子，代码如下：

/*?* 陈刚 ,创建日期 2004-6-10?* ?* Email: glchengang@yeah.net ?* Blog : glchengang.yeah.net?*/package net.yeah.glchengang.layout;

import org.Eclipse.SWT.SWT;import org.Eclipse.SWT.custom.StackLayout;import org.Eclipse.SWT.events.SelectionAdapter;import org.Eclipse.SWT.events.SelectionEvent;import org.Eclipse.SWT.events.SelectionListener;import org.Eclipse.SWT.layout.FillLayout;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.Shell;import org.Eclipse.SWT.widgets.Text;

public class StackLayoutApp {

??? /*???? * 因为要在按钮b1,b2的事件中调用，所以以下变量必须定义成属性（类变量）???? * 否则在按钮b1,b2的事件中是访问不到的???? */??? private Composite c;??? private Text t1;??? private Text t2;??? private Text t3;??? private StackLayout stackLayout = new StackLayout();

??? public static void main(String[] args) {??????? StackLayoutApp window = new StackLayoutApp();??????? window.open();??? }??? public void open() {??????? Display display = new Display();??????? Shell shell = new Shell();??????? shell.setLayout(new FillLayout());??????? shell.setText("SWT Application");??????? //--------------核心代码如下:start------------------------ ??????? {??????????? /*???????????? * 在c面板下有两个Text框，因为c为stackLayout布局，???????????? * 所以这两个Text框是重叠在一起的???????????? */??????????? c = new Composite(shell, SWT.NONE);??????????? c.setLayout(stackLayout);

??????????? t1 = new Text(c, SWT.BORDER);??????????? t1.setText("11111111111111");

??????????? t2 = new Text(c, SWT.BORDER);??????????? t2.setText("222222222222");??????? }??????? {??????????? /*???????????? * 建立两个按钮来改变上面两个text框的显示???????????? */??????????? Composite composite = new Composite(shell, SWT.NONE);??????????? composite.setLayout(new RowLayout());

??????????? Button b1 = new Button(composite, SWT.NONE);??????????? b1.setText("显示111111111");??????????? b1.addSelectionListener(new SelectionListener() { //点击事件　??????????????? public void widgetSelected(SelectionEvent e) {??????????????????? /*****************************************************???????????????????? * --------下面两句是StackLayout的关键----------------???????????????????? ****************************************************/??????????????????? stackLayout.topControl = t1; //将t1框显示??????????????????? c.layout(); //将界面刷新一下,否则显示上会没任何反映的??????????????? }??????????????? public void widgetDefaultSelected(SelectionEvent e) {}??????????? });

??????????? Button b2 = new Button(composite, SWT.NONE);??????????? b2.setText("显示2222222222");??????????? //这里也可以用SelectionAdapter这个适配器，它是SelectionListener的空实现??????????? b2.addSelectionListener(new SelectionAdapter() {??????????????? public void widgetSelected(SelectionEvent e) {??????????????????? stackLayout.topControl = t2;??????????????????? c.layout();??????????????? }??????????? });

??????? }

??????? //--------------核心代码如上:end------------------------??????? ??????? shell.open();??????? while (!shell.isDisposed()) {??????????? if (!display.readAndDispatch())??????????????? display.sleep();??????? }??? }}

运行效果图如下：

点击按钮"显示11111"时，图变化如下：

点击按钮"显示22222"时，图变化如下：