Java tutorial
/******************************************************************************* * All Right Reserved. Copyright (c) 1998, 2004 Jackwind Li Guojie * * Created on Feb 23, 2004 8:40:41 PM by JACK $Id$ * ******************************************************************************/ import java.io.BufferedReader; import java.io.File; import java.io.FileReader; import java.io.FileWriter; import java.io.IOException; import org.eclipse.jface.action.Action; import org.eclipse.jface.action.IAction; import org.eclipse.jface.action.MenuManager; import org.eclipse.jface.action.Separator; import org.eclipse.jface.action.ToolBarManager; import org.eclipse.jface.resource.ImageDescriptor; import org.eclipse.jface.resource.ImageRegistry; import org.eclipse.swt.SWT; import org.eclipse.swt.custom.StyledText; import org.eclipse.swt.events.ModifyEvent; import org.eclipse.swt.events.ModifyListener; import org.eclipse.swt.graphics.Font; import org.eclipse.swt.graphics.Image; import org.eclipse.swt.layout.GridData; import org.eclipse.swt.layout.GridLayout; import org.eclipse.swt.widgets.Decorations; import org.eclipse.swt.widgets.Display; import org.eclipse.swt.widgets.FileDialog; import org.eclipse.swt.widgets.MenuItem; import org.eclipse.swt.widgets.MessageBox; import org.eclipse.swt.widgets.Shell; import org.eclipse.swt.widgets.ToolBar; public class BasicEditor2 { Display display = new Display(); Shell shell = new Shell(display); // The control used for text displaying and editing. StyledText text; // Is there any changes since last saving action? boolean hasUnsavedChanges; // The file associated with current text content. File file; // The recent directory private String lastOpenDirectory; // The name of this program. public static final String APP_NAME = "BasicEditor v2.0"; MenuItem miWrap = null; public BasicEditor2() { // Action: create new text. Action actionNew = new Action("&New", ImageDescriptor.createFromFile(null, "icons/new.gif")) { public void run() { if (handleChangesBeforeDiscard()) { file = null; text.setText(""); } } }; actionNew.setAccelerator(SWT.CTRL + 'N'); // Action: open a text file. Action actionOpen = new Action("&Open", ImageDescriptor.createFromFile(null, "icons/open.gif")) { public void run() { if (handleChangesBeforeDiscard()) loadTextFromFile(); } }; actionOpen.setAccelerator(SWT.CTRL + 'O'); // Action: save the text to a file. Action actionSave = new Action("&Save\tCtrl+S", ImageDescriptor.createFromFile(null, "icons/save.gif")) { public void run() { saveTextToFile(); } }; //actionSave.setAccelerator(SWT.CTRL + 'S'); // Action: copy selected text. Action actionCopy = new Action("&Copy", ImageDescriptor.createFromFile(null, "icons/copy.gif")) { public void run() { text.copy(); } }; actionCopy.setAccelerator(SWT.CTRL + 'C'); // Separator. // Action: cut the selected text. Action actionCut = new Action("Cu&t", ImageDescriptor.createFromFile(null, "icons/cut.gif")) { public void run() { text.cut(); } }; actionCut.setAccelerator(SWT.CTRL + 'X'); // Action: paste the text on clipboard. Action actionPaste = new Action("&Paste", ImageDescriptor.createFromFile(null, "icons/paste.gif")) { public void run() { text.paste(); } }; actionPaste.setAccelerator(SWT.CTRL + 'P'); // Separator. // Action: set wrap property. Action actionWrap = new Action("&Wrap", IAction.AS_CHECK_BOX) { public void run() { text.setWordWrap(isChecked()); } }; actionWrap.setAccelerator(SWT.CTRL + 'W'); // Action: exit. Action actionExit = new Action("&Exit@Ctrl+X") { public void run() { if (handleChangesBeforeDiscard()) shell.dispose(); } }; System.out.println(actionWrap.getText()); // Add a tool bar. ToolBar toolBar = new ToolBar(shell, SWT.FLAT | SWT.RIGHT); ToolBarManager toolBarManager = new ToolBarManager(toolBar); toolBarManager.add(actionNew); toolBarManager.add(actionOpen); toolBarManager.add(actionSave); toolBarManager.add(new Separator()); toolBarManager.add(actionCopy); toolBarManager.add(actionCut); toolBarManager.add(actionPaste); toolBarManager.add(new Separator()); toolBarManager.add(actionWrap); toolBarManager.update(true); shell.setLayout(new GridLayout()); System.out.println("Client area: " + shell.getClientArea()); text = new StyledText(shell, SWT.MULTI | SWT.WRAP | SWT.BORDER | SWT.H_SCROLL | SWT.V_SCROLL); text.setLayoutData(new GridData(GridData.FILL_BOTH)); Font font = new Font(shell.getDisplay(), "Courier New", 10, SWT.NORMAL); text.setFont(font); text.setText("BasicEditor version 1.0\r\nWriten by Jack Li Guojie. "); text.addModifyListener(new ModifyListener() { public void modifyText(ModifyEvent e) { hasUnsavedChanges = true; } }); // Add menus. MenuManager barMenuManager = new MenuManager(); MenuManager fileMenuManager = new MenuManager("&File"); MenuManager editMenuManager = new MenuManager("&Edit"); MenuManager formatMenuManager = new MenuManager("&Format"); barMenuManager.add(fileMenuManager); barMenuManager.add(editMenuManager); barMenuManager.add(formatMenuManager); fileMenuManager.add(actionNew); fileMenuManager.add(actionOpen); fileMenuManager.add(actionSave); fileMenuManager.add(new Separator()); fileMenuManager.add(actionExit); editMenuManager.add(actionCopy); editMenuManager.add(actionCut); editMenuManager.add(actionPaste); formatMenuManager.add(actionWrap); // Add the menu bar to the shell. // shell.setMenuBar(menuBar); barMenuManager.updateAll(true); shell.setMenuBar(barMenuManager.createMenuBar((Decorations) shell)); shell.setSize(400, 200); shell.open(); // Set up the event loop. while (!shell.isDisposed()) { if (!display.readAndDispatch()) { // If no more entries in event queue display.sleep(); } } display.dispose(); } ImageRegistry imageRegistry = new ImageRegistry(); /** * Retrieves the image corresponding to the given file name. Note that the * image is managed by an image registry. You should not dispose the image * after use. * * @param shortFileName * @return */ private Image getImage(String shortFileName) { if (imageRegistry.getDescriptor(shortFileName) == null) { ImageDescriptor descriptor = ImageDescriptor.createFromFile(null, "icons/" + shortFileName); imageRegistry.put(shortFileName, descriptor); } return imageRegistry.get(shortFileName); } /** * Hands unsaved changes before the text is discarded. * * @return whether furthur action should be carried on. */ boolean handleChangesBeforeDiscard() { if (!hasUnsavedChanges) return true; MessageBox messageBox = new MessageBox(shell, SWT.ICON_WARNING | SWT.YES | SWT.NO | SWT.CANCEL); messageBox.setMessage("Do you want to save the changes to " + (file == null ? "a file?" : file.getName())); messageBox.setText(APP_NAME); int ret = messageBox.open(); if (ret == SWT.YES) { return saveTextToFile(); } else if (ret == SWT.NO) { return true; } else { return false; } } /** * Loads the text from a file selected by the user. * * @return the status of the operation. */ boolean loadTextFromFile() { FileDialog dialog = new FileDialog(shell, SWT.OPEN); if (lastOpenDirectory != null) dialog.setFilterPath(lastOpenDirectory); String selectedFile = dialog.open(); if (selectedFile == null) { log("Action cancelled: loading the text from a file"); return false; } file = new File(selectedFile); lastOpenDirectory = file.getParent(); try { BufferedReader reader = new BufferedReader(new FileReader(file)); StringBuffer sb = new StringBuffer(); String line = null; while ((line = reader.readLine()) != null) { sb.append(line); sb.append("\r\n"); } text.setText(sb.toString()); return true; } catch (IOException e) { log("Failed to load the text from file: " + file); log(e.toString()); } return false; } /** * Saves the content of the styled text to the file. If the file has not * been specified yet, a FileDialog prompts up for the user to select a * file. * * @return the status of the operation. * @throws IOException */ boolean saveTextToFile() { if (file == null) { FileDialog dialog = new FileDialog(shell, SWT.SAVE); if (lastOpenDirectory != null) dialog.setFilterPath(lastOpenDirectory); String selectedFile = dialog.open(); if (selectedFile == null) { log("Action cancelled: saving the text to a file"); return false; } file = new File(selectedFile); lastOpenDirectory = file.getParent(); } try { FileWriter writer = new FileWriter(file); writer.write(text.getText()); writer.close(); log("The text has been saved to file: " + file); hasUnsavedChanges = false; return true; } catch (IOException e) { log("Failed to save the text to file: " + file); log(e.toString()); } return false; } /** * Logs system messages. * * @param message */ void log(String message) { System.out.println(message); } public static void main(String[] args) { new BasicEditor2(); } }