Extending the GUI - Beginning Java 2 SDK - page 909

tempElement = createElement(start, last); // No, so create one
} else {
tempElement.draw(g2D); // Yes - draw to erase it
tempElement.modify(start, last); // Modify it
}
tempElement.draw(g2D); // and draw it
} else if(button1Down && mode == MOVE && selectedElement != null) {
selectedElement.draw(g2D); // Draw to erase the element
selectedElement.move(last.x-start.x, last.y-start.y); // Move it
selectedElement.draw(g2D); // Draw in its new position
start = last; // Make start current point
}
}
Now we only execute the previous code in NORMAL mode. For MOVE mode, if button 1 is down and
there is an element selected to move, we move it by erasing it at the current position, moving the
element by calling its move() method, and drawing it at the new position. The current last will be
start for the next MOUSE _ DRAGGED event.
The final alterations to our code occur in the mouseReleased() method:
public void mouseReleased(MouseEvent e) {
if(e.isPopupTrigger()) {
start = e.getPoint();
if(highlightElement==null)
theApp.getWindow().getPopup().show((Component)e.getSource(),
start.x, start.y);
else
elementPopup.show((Component)e.getSource(), start.x, start.y);
} else if((e.getButton()==MouseEvent.BUTTON1) &&
(theApp.getWindow().getElementType() != TEXT) && mode == NORMAL) {
button1Down = false; // Reset the button 1 flag
if(tempElement != null) {
theApp.getModel().add(tempElement); // Add element to the model
tempElement = null; // No temporary element now stored
}
} else if((e.getButton()==MouseEvent.BUTTON1) &&
(mode == MOVE || mode == ROTATE)) {
button1Down = false; // Reset the button 1 flag
if(selectedElement != null)
repaint();
mode = NORMAL;
}
if(g2D != null) {
g2D.dispose(); // Release graphic context resource
g2D = null; // Set it to null
}