一、SWT简介
Java语言的声望和它在桌面应用程序(GUI程序)所取得的成就显然极不相符,至今仍然很少能看到非常成功Java桌面程序。虽然有JBuilder,Netbean,JProbe等大型软件作为代表,但这仍不能证明Java的GUI程序是成功的:它们的外观总是和同一操作系统平台下的其它软件显得格格不入。对机器配置的需求也似乎永无止境,这使得它们只能被一些总是拥有当前最高性能PC的程序员们所容忍,或是那些不在乎金钱和时间的专业用户所接受。对绝大多数计算机使用者来说,AWT或SWING代表着怪异的界面和无法接受的速度。Standard Widget Toolkit(SWT)或许是Java这一噩梦的终结者,广大Java程序员终于可以开发出高效率的GUI程序,它们拥有标准的外观,几乎没有人能看出你的程序是用Java写出来的,更为重要的是,这些程序是跨平台的。
SWT本身仅仅是Eclipse组织为了开发Eclipse IDE环境所编写的一组底层图形界面 API。或许是无心插柳,或是有意为之,至今为止,SWT无论是在性能和外观上,都超越了SUN公司提供的AWT和SWING。目前Eclipse IDE已经开发到了2.1版本,SWT已经十分稳定。这里指的稳定应该包含两层意思:
一是指性能上的稳定,其中的关键是源于SWT的设计理念。SWT最大化了操作系统的图形构件API,就是说只要操作系统提供了相应图形的构件,那么SWT只是简单应用JNI技术调用它们,只有那些操作系统中不提供的构件,SWT才自己去做一个模拟的实现。可以看出SWT的性能上的稳定大多时候取决于相应操作系统图形构件的稳定性。
另一个稳定是指SWT API包中的类、方法的名称和结构已经少有改变,程序员不用担心由于Eclipse组织开发进度很快(Eclipse IDE每天都会有一个Nightly版本的发布),而导致自己的程序代码变化过大。从一个版本的SWT更新至另一版本,通常只需要简单将SWT包换掉就可以了。
二、Eclipse3.0的SWT编程
1.SWT比AWT和Swing要快多,因为它是利用操作系统的界面组件生成UI的,在java桌面设计领域掀起一场革命
2.环境配置:
windows系统+eclipse3.0
3.具体操作:
(1).新建一java项目,命名SWT,文件结构如下:
+swt
+bin(编译输出)
+src(原文件)
+AddressBookUI.java
+swt-awt-win32-3062.dll(以下均从eclipse/plugins/org.eclipse.swt.win32_3.0.1/os/win32/x86下导入)
+swt-win32-3062.dll
+javaw.exe.manifest
(2).到项目的properties里,在java build path | libraries里将swt.jar导入
(3).AddressBookUI.java原代码如下:
import org.eclipse.swt.widgets.Display;<br />import org.eclipse.swt.widgets.Shell;<br />import org.eclipse.swt.SWT;<br />import org.eclipse.swt.widgets.Button;<br />import org.eclipse.swt.widgets.Group;<br />import org.eclipse.swt.widgets.Label;<br />import org.eclipse.swt.widgets.Text;<br />import org.eclipse.swt.widgets.*;<br />import org.eclipse.swt.events.SelectionAdapter;<br />import org.eclipse.swt.events.SelectionEvent;<br />public class AddressBookUI {<br /> private Shell shell;<br /> private Text miscText;<br /> private Text addrText;<br /> private Text emailText;<br /> private Text phoneText;<br /> private Text lnameText;<br /> private Text fnameText;<br /> private Button cancelButton;<br /> private Button saveButton;<br /> private Button nextButton;<br /> private Button prevButton;<br /> private Button editButton;<br /> private Button deleteButton;<br /> private Button newButton;<br /> public static void main(String[] args) {<br /> AddressBookUI window = new AddressBookUI();<br /> window.open();<br /> }<br /> public void open() {<br /> final Display display = new Display();<br /> shell = new Shell();<br /> shell.setSize(610, 477);<br /> shell.setText("Address Book");<br /> {<br /> newButton = new Button(shell, SWT.NONE);<br /> newButton.addSelectionListener(new SelectionAdapter() {<br /> public void widgetSelected(SelectionEvent e) {<br /> clearText(); <br /> setTextEditable(true);<br /> enableEditButtons(false);<br /> enableSaveButtons(true);<br /> System.out.println("New button selected.");<br /> }<br /> });<br /> newButton.setBounds(10, 380, 75, 35);<br /> newButton.setText("New");<br /> }<br /> {<br /> deleteButton = new Button(shell, SWT.NONE);<br /> deleteButton.addSelectionListener(new SelectionAdapter() {<br /> public void widgetSelected(SelectionEvent e) {<br /> clearText();<br /> System.out.println("Delete button selected.");<br /> }<br /> });<br /> deleteButton.setBounds(85, 380, 75, 35);<br /> deleteButton.setText("Delete");<br /> }<br /> {<br /> editButton = new Button(shell, SWT.NONE);<br /> editButton.addSelectionListener(new SelectionAdapter() {<br /> public void widgetSelected(SelectionEvent e) {<br /> setTextEditable(true);<br /> enableEditButtons(false);<br /> enableSaveButtons(true);<br /> <br /> System.out.println("Edit button selected."); <br /> }<br /> });<br /> editButton.setBounds(160, 380, 75, 35);<br /> editButton.setText("Edit");<br /> }<br /> {<br /> prevButton = new Button(shell, SWT.NONE);<br /> prevButton.addSelectionListener(new SelectionAdapter() {<br /> public void widgetSelected(SelectionEvent e) {<br /> System.out.println("Previous button selected.");<br /> }<br /> });<br /> prevButton.setBounds(265, 380, 75, 35);<br /> prevButton.setText("Previous");<br /> }<br /> {<br /> nextButton = new Button(shell, SWT.NONE);<br /> nextButton.addSelectionListener(new SelectionAdapter() {<br /> public void widgetSelected(SelectionEvent e) {<br /> System.out.println("Next button selected.");<br /> }<br /> });<br /> nextButton.setBounds(340, 380, 75, 35);<br /> nextButton.setText("Next");<br /> }<br /> {<br /> saveButton = new Button(shell, SWT.NONE);<br /> saveButton.addSelectionListener(new SelectionAdapter() {<br /> public void widgetSelected(SelectionEvent e) {<br /> setTextEditable(false);<br /> enableEditButtons(true);<br /> enableSaveButtons(false);<br /> <br /> System.out.println("Save button selected."); <br /> }<br /> });<br /> saveButton.setBounds(445, 380, 75, 35);<br /> saveButton.setText("Save");<br /> saveButton.setEnabled(false);<br /> }<br /> {<br /> cancelButton = new Button(shell, SWT.NONE);<br /> cancelButton.addSelectionListener(new SelectionAdapter() {<br /> public void widgetSelected(SelectionEvent e) {<br /> setTextEditable(false);<br /> enableEditButtons(true);<br /> enableSaveButtons(false);<br /> System.out.println("Cancel button selected."); <br /> }<br /> });<br /> cancelButton.setBounds(520, 380, 75, 35);<br /> cancelButton.setText("Cancel");<br /> cancelButton.setEnabled(false);<br /> }<br /> {<br /> final Group group = new Group(shell, SWT.NONE);<br /> group.setText("Details");<br /> group.setBounds(10, 10, 585, 355);<br /> {<br /> final Label label = new Label(group, SWT.NONE);<br /> label.setBounds(10, 20, 135, 25);<br /> label.setText("First Name:");<br /> }<br /> {<br /> final Label label = new Label(group, SWT.NONE);<br /> label.setBounds(10, 60, 135, 25);<br /> label.setText("Last Name:");<br /> }<br /> {<br /> final Label label = new Label(group, SWT.NONE);<br /> label.setBounds(10, 100, 135, 25);<br /> label.setText("Phone:");<br /> }<br /> {<br /> final Label label = new Label(group, SWT.NONE);<br /> label.setBounds(10, 140, 135, 25);<br /> label.setText("Email:");<br /> }<br /> {<br /> final Label label = new Label(group, SWT.NONE);<br /> label.setBounds(10, 180, 135, 25);<br /> label.setText("Address:");<br /> }<br /> {<br /> final Label label = new Label(group, SWT.NONE);<br /> label.setBounds(10, 255, 135, 25);<br /> label.setText("Miscellaneous Information:");<br /> }<br /> {<br /> fnameText = new Text(group, SWT.BORDER | SWT.READ_ONLY);<br /> fnameText.setBounds(150, 15, 420, 25);<br /> }<br /> {<br /> lnameText = new Text(group, SWT.BORDER | SWT.READ_ONLY);<br /> lnameText.setBounds(150, 55, 420, 25);<br /> }<br /> {<br /> phoneText = new Text(group, SWT.BORDER | SWT.READ_ONLY);<br /> phoneText.setBounds(150, 95, 420, 25);<br /> }<br /> {<br /> emailText = new Text(group, SWT.BORDER | SWT.READ_ONLY);<br /> emailText.setBounds(150, 135, 420, 25);<br /> }<br /> {<br /> addrText = new Text(group, SWT.BORDER | SWT.READ_ONLY | SWT.V_SCROLL);<br /> addrText.setBounds(150, 175, 420, 60);<br /> }<br /> {<br /> miscText = new Text(group, SWT.BORDER | SWT.READ_ONLY | SWT.V_SCROLL);<br /> miscText.setBounds(150, 250, 420, 65);<br /> }<br /> }<br /> setupMenu();<br /> shell.open();<br /> while (!shell.isDisposed()) {<br /> if (!display.readAndDispatch())<br /> display.sleep();<br /> }<br />}<br />private void setupMenu() {<br /> //create the menu bar<br /> Menu menu = new Menu(shell, SWT.BAR);<br /> shell.setMenuBar(menu);<br /> //add the File option to it<br /> MenuItem file = new MenuItem(menu, SWT.CASCADE);<br /> file.setText("File");<br /> //create a menu for the File option<br /> file.setMenu(new Menu(file));<br /> //add MenuItems to the File menu<br /> MenuItem prevItem = new MenuItem(new Menu(file), SWT.NONE);<br /> prevItem.setText("Previous");<br /> MenuItem nextItem = new MenuItem(new Menu(file), SWT.PUSH);<br /> nextItem.setText("Next");<br /> MenuItem seperaTor = new MenuItem(new Menu(file), SWT.SEPARATor);<br /> MenuItem quitItem = new MenuItem(new Menu(file), SWT.PUSH);<br /> quitItem.setText("Quit");<br /> //add listeners for the actions<br /> prevItem.addListener(SWT.Selection, new Listener() {<br /> public void handleEvent(Event e) {<br /> System.out.println("Previous menu item selected.");<br /> }<br /> });<br /> nextItem.addListener(SWT.Selection, new Listener() {<br /> public void handleEvent(Event e) {<br /> System.out.println("Next menu item selected.");<br /> }<br /> });<br /> quitItem.addListener(SWT.Selection, new Listener() {<br /> public void handleEvent(Event e) {<br /> shell.dispose();<br /> }<br /> });<br />}<br />private void clearText() {<br /> fnameText.setText("");<br /> lnameText.setText("");<br /> phoneText.setText("");<br /> emailText.setText("");<br /> addrText.setText("");<br /> miscText.setText(""); <br />}<br />private void setTextEditable(boolean editable) {<br /> fnameText.setEditable(editable);<br /> lnameText.setEditable(editable);<br /> phoneText.setEditable(editable);<br /> emailText.setEditable(editable);<br /> addrText.setEditable(editable);<br /> miscText.setEditable(editable);<br />}<br />private void enableEditButtons(boolean enable) {<br /> newButton.setEnabled(enable);<br /> deleteButton.setEnabled(enable);<br /> editButton.setEnabled(enable);<br />}<br />private void enableSaveButtons(boolean enable) {<br /> saveButton.setEnabled(enable);<br /> cancelButton.setEnabled(enable); <br />}<br />}
(4).测试运行,run就可以啦
一个有信念者所开发出的力量,大于99个只有兴趣者。