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; import org.eclipse.swt.widgets.Shell; import org.eclipse.swt.SWT; import org.eclipse.swt.widgets.Button; import org.eclipse.swt.widgets.Group; import org.eclipse.swt.widgets.Label; import org.eclipse.swt.widgets.Text; import org.eclipse.swt.widgets.*; import org.eclipse.swt.events.SelectionAdapter; import org.eclipse.swt.events.SelectionEvent; public class AddressBookUI { private Shell shell; private Text miscText; private Text addrText; private Text emailText; private Text phoneText; private Text lnameText; private Text fnameText; private Button cancelButton; private Button saveButton; private Button nextButton; private Button prevButton; private Button editButton; private Button deleteButton; private Button newButton; public static void main(String[] args) { AddressBookUI window = new AddressBookUI(); window.open(); } public void open() { final Display display = new Display(); shell = new Shell(); shell.setSize(610, 477); shell.setText("Address Book"); { newButton = new Button(shell, SWT.NONE); newButton.addSelectionListener(new SelectionAdapter() { public void widgetSelected(SelectionEvent e) { clearText(); setTextEditable(true); enableEditButtons(false); enableSaveButtons(true);
System.out.println("New button selected."); } }); newButton.setBounds(10, 380, 75, 35); newButton.setText("New"); } { deleteButton = new Button(shell, SWT.NONE); deleteButton.addSelectionListener(new SelectionAdapter() { public void widgetSelected(SelectionEvent e) { clearText();
System.out.println("Delete button selected."); } }); deleteButton.setBounds(85, 380, 75, 35); deleteButton.setText("Delete"); } { editButton = new Button(shell, SWT.NONE); editButton.addSelectionListener(new SelectionAdapter() { public void widgetSelected(SelectionEvent e) { setTextEditable(true); enableEditButtons(false); enableSaveButtons(true); System.out.println("Edit button selected."); } }); editButton.setBounds(160, 380, 75, 35); editButton.setText("Edit"); } { prevButton = new Button(shell, SWT.NONE); prevButton.addSelectionListener(new SelectionAdapter() { public void widgetSelected(SelectionEvent e) { System.out.println("Previous button selected."); } }); prevButton.setBounds(265, 380, 75, 35); prevButton.setText("Previous"); } { nextButton = new Button(shell, SWT.NONE); nextButton.addSelectionListener(new SelectionAdapter() { public void widgetSelected(SelectionEvent e) { System.out.println("Next button selected."); } }); nextButton.setBounds(340, 380, 75, 35); nextButton.setText("Next"); } { saveButton = new Button(shell, SWT.NONE); saveButton.addSelectionListener(new SelectionAdapter() { public void widgetSelected(SelectionEvent e) { setTextEditable(false); enableEditButtons(true); enableSaveButtons(false); System.out.println("Save button selected."); } }); saveButton.setBounds(445, 380, 75, 35); saveButton.setText("Save"); saveButton.setEnabled(false); } { cancelButton = new Button(shell, SWT.NONE); cancelButton.addSelectionListener(new SelectionAdapter() { public void widgetSelected(SelectionEvent e) { setTextEditable(false); enableEditButtons(true); enableSaveButtons(false);
System.out.println("Cancel button selected."); } }); cancelButton.setBounds(520, 380, 75, 35); cancelButton.setText("Cancel"); cancelButton.setEnabled(false); } { final Group group = new Group(shell, SWT.NONE); group.setText("Details"); group.setBounds(10, 10, 585, 355); { final Label label = new Label(group, SWT.NONE); label.setBounds(10, 20, 135, 25); label.setText("First Name:"); } { final Label label = new Label(group, SWT.NONE); label.setBounds(10, 60, 135, 25); label.setText("Last Name:"); } { final Label label = new Label(group, SWT.NONE); label.setBounds(10, 100, 135, 25); label.setText("Phone:"); } { final Label label = new Label(group, SWT.NONE); label.setBounds(10, 140, 135, 25); label.setText("Email:"); } { final Label label = new Label(group, SWT.NONE); label.setBounds(10, 180, 135, 25); label.setText("Address:"); } { final Label label = new Label(group, SWT.NONE); label.setBounds(10, 255, 135, 25); label.setText("Miscellaneous Information:"); } { fnameText = new Text(group, SWT.BORDER | SWT.READ_ONLY); fnameText.setBounds(150, 15, 420, 25); } { lnameText = new Text(group, SWT.BORDER | SWT.READ_ONLY); lnameText.setBounds(150, 55, 420, 25); } { phoneText = new Text(group, SWT.BORDER | SWT.READ_ONLY); phoneText.setBounds(150, 95, 420, 25); } { emailText = new Text(group, SWT.BORDER | SWT.READ_ONLY); emailText.setBounds(150, 135, 420, 25); } { addrText = new Text(group, SWT.BORDER | SWT.READ_ONLY | SWT.V_SCROLL); addrText.setBounds(150, 175, 420, 60); } { miscText = new Text(group, SWT.BORDER | SWT.READ_ONLY | SWT.V_SCROLL); miscText.setBounds(150, 250, 420, 65); } }
setupMenu();
shell.open(); while (!shell.isDisposed()) { if (!display.readAndDispatch()) display.sleep(); } }
private void setupMenu() { //create the menu bar Menu menu = new Menu(shell, SWT.BAR); shell.setMenuBar(menu); //add the File option to it MenuItem file = new MenuItem(menu, SWT.CASCADE); file.setText("File"); //create a menu for the File option file.setMenu(new Menu(file)); //add MenuItems to the File menu MenuItem prevItem = new MenuItem(new Menu(file), SWT.NONE); prevItem.setText("Previous");
MenuItem nextItem = new MenuItem(new Menu(file), SWT.PUSH); nextItem.setText("Next");
MenuItem seperator = new MenuItem(new Menu(file), SWT.SEPARATOR); MenuItem quitItem = new MenuItem(new Menu(file), SWT.PUSH); quitItem.setText("Quit"); //add listeners for the actions prevItem.addListener(SWT.Selection, new Listener() { public void handleEvent(Event e) { System.out.println("Previous menu item selected."); } }); nextItem.addListener(SWT.Selection, new Listener() { public void handleEvent(Event e) { System.out.println("Next menu item selected."); } }); quitItem.addListener(SWT.Selection, new Listener() { public void handleEvent(Event e) { shell.dispose(); } }); }
private void clearText() { fnameText.setText(""); lnameText.setText(""); phoneText.setText(""); emailText.setText(""); addrText.setText(""); miscText.setText(""); }
private void setTextEditable(boolean editable) { fnameText.setEditable(editable); lnameText.setEditable(editable); phoneText.setEditable(editable); emailText.setEditable(editable); addrText.setEditable(editable); miscText.setEditable(editable); }
private void enableEditButtons(boolean enable) { newButton.setEnabled(enable); deleteButton.setEnabled(enable); editButton.setEnabled(enable); }
private void enableSaveButtons(boolean enable) { saveButton.setEnabled(enable); cancelButton.setEnabled(enable); } } | (4).测试运行,run就可以啦 |