import org.eclipse.swt.*;
import org.eclipse.swt.events.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.widgets.*;
import org.eclipse.swt.layout.*;
/**
* A simple SWT based program to handle the moving of an composite widget (Tomcat)
* on a canvas. It includes the code for,
*
* - handling the movement of a widget by the user using the mouse
* - pull-down menus
* - popup menus associated with a widget
* - use of images on a label
*
* @author Asanga Udugama (adu@comnets.uni-bremen.de)
*
*
*/
public class SWTTest implements Runnable {
Shell shell;
Display display;
Composite displayComp;
int beginX, beginY, locX, locY;
boolean mouseDown;
Label titleLabel, imageLabel;
/**
* Main thread method handling the view.
*
*/
public void run() {
ImageData imageData;
Image image;
display = new Display();
shell = new Shell(display, SWT.SHELL_TRIM);
shell.setLocation(1, 1);
shell.setMaximized(true);
shell.setText("SWT Test");
// setup title bar image
imageData = null;
try {
imageData = new ImageData(getClass().getClassLoader()
.getResource("images/eclipse.jpg").openStream());
} catch(Exception e) {
System.out.println(e.toString());
System.exit(1);
}
image = new Image(display, imageData);
shell.setImage(image);
// setup pull down menus
setupDropDownMenus();
//
setupDisplayItem();
// start the display loop
shell.open();
while(!shell.isDisposed()) {
if(!display.readAndDispatch())
display.sleep();
}
image.dispose ();
display.dispose();
}
/**
* Method to build the drop down menus of the view.
*
*/
void setupDropDownMenus() {
Menu mainMenuBar;
MenuItem actionsMenuItem;
Menu actionsMenu;
MenuItem quitMenuItem;
// setup the main menu bar
mainMenuBar = new Menu(shell, SWT.BAR);
shell.setMenuBar(mainMenuBar);
// setup the actions pull down
actionsMenuItem = new MenuItem(mainMenuBar, SWT.CASCADE);
actionsMenuItem.setText("Actions");
actionsMenu = new Menu(shell, SWT.DROP_DOWN);
actionsMenuItem.setMenu(actionsMenu);
// setup object appear menu item and event handler
quitMenuItem = new MenuItem(actionsMenu, SWT.PUSH);
quitMenuItem.setText("Make Tomcat Visible");
quitMenuItem.addListener(SWT.Selection, new Listener() {
public void handleEvent(Event e) {
displayComp.setVisible(true);
}
});
// setup quit menu item and event handler
quitMenuItem = new MenuItem(actionsMenu, SWT.PUSH);
quitMenuItem.setText("Quit");
quitMenuItem.addListener(SWT.Selection, new Listener() {
public void handleEvent(Event e) {
display.dispose();
System.exit(0);
}
});
}
/**
* Method to create the composite widget shown on the view that is able to be moved
* using the mouse.
*
*/
void setupDisplayItem() {
Point compSize, labelSize;
ImageData imageData;
Image image;
// setup the composite
locX = 10;
locY = 10;
displayComp = new Composite(shell, SWT.BORDER);
displayComp.setBackground(display.getSystemColor(SWT.COLOR_CYAN));
displayComp.setLocation(locX, locY);
displayComp.setSize(150, 150);
displayComp.addMouseListener(new CommonMouseHandler());
displayComp.addMouseMoveListener(new CommonMouseHandler());
displayComp.setMenu(buildPopupMenu());
displayComp.setLayout( new FillLayout());
// setup title label
titleLabel = new Label(displayComp, SWT.BORDER);
titleLabel.setText("Tomcat");
titleLabel.pack();
titleLabel.addMouseListener(new CommonMouseHandler());
titleLabel.addMouseMoveListener(new CommonMouseHandler());
titleLabel.setMenu(buildPopupMenu());
compSize = displayComp.getSize();
labelSize = titleLabel.getSize();
titleLabel.setLocation((compSize.x - labelSize.x) / 2, 5);
// setup image label
imageData = null;
try {
imageData = new ImageData(getClass().getClassLoader().getResource("images/tomcat.gif").openStream());
} catch(Exception e) {
System.out.println(e.toString());
System.exit(1);
}
image = new Image(display, imageData);
imageLabel = new Label(displayComp, SWT.BORDER);
imageLabel.setImage(image);
imageLabel.pack();
imageLabel.addMouseListener(new CommonMouseHandler());
imageLabel.addMouseMoveListener(new CommonMouseHandler());
imageLabel.setMenu(buildPopupMenu());
compSize = displayComp.getSize();
labelSize = imageLabel.getSize();
System.out.println(labelSize.x);
imageLabel.setLocation((compSize.x - labelSize.x) / 2, 30);
}
/**
* Method to build the popup menu items for making the widget
* dissapear.
*/
public Menu buildPopupMenu() {
Menu popupmenu;
MenuItem actionItem;
// setup main menu
popupmenu = new Menu(shell, SWT.POP_UP);
// setup make visible menu items & handler
actionItem = new MenuItem(popupmenu, SWT.PUSH);
actionItem.setText("Make Tomcat Invisivle");
actionItem.addListener(SWT.Selection, new Listener() {
public void handleEvent(Event e) {
displayComp.setVisible(false);
mouseDown = false;
}
});
// setup the cancel menu item and the even handler
actionItem = new MenuItem(popupmenu, SWT.PUSH);
actionItem.setText("Cancel");
return popupmenu;
}
/**
* An inner class that handles the mouse events on the displayed widget for
* the purpose of handling user mouse actions on the displayed widget.
*
*/
class CommonMouseHandler extends MouseAdapter implements MouseMoveListener {
/**
* When user clicks the right mouse on a widget setup
* for a possible movement of the widget in the view
*/
public void mouseDown (MouseEvent event) {
mouseDown = true;
beginX = event.x;
beginY = event.y;
}
/**
* When user releases the right mouse on a widget
* move widget to new location.
*/
public void mouseUp (MouseEvent event) {
mouseDown = false;
locX += (event.x - beginX);
locY += (event.y - beginY);
displayComp.setLocation(locX, locY);
}
/**
* When mouse is down and user moves cursor, move the widget
* on the view.
*/
public void mouseMove (MouseEvent event) {
if(mouseDown) {
locX += (event.x - beginX);
locY += (event.y - beginY);
displayComp.setLocation(locX, locY);
}
}
}
/**
* Main method starting the application.
*
* @param String args - command line arguments
*/
public static void main(String args[]) {
SWTTest swtTest;
Thread displayThread;
swtTest = new SWTTest();
displayThread = new Thread(swtTest);
displayThread.start();
try {
displayThread.join();
} catch(Exception e) {
System.out.println(e.toString());
System.exit(1);
}
}
}