Trail: Creating a GUI With JFC/Swing
Lesson: Drag and Drop and Data Transfer
Drop Location Rendering
Home Page > Creating a GUI With JFC/Swing > Drag and Drop and Data Transfer

Drop Location Rendering

This is a more advanced topic and most people do not need to worry about it. However, if you have a custom component you will need to handle the drop location rendering yourself.

You can register to be notified whenever the dropLocation property changes. You would listen for this change and do your own rendering of the drop location in a custom renderer for the component or in the paintComponent method, using the getDropLocation method.

Here is an example of listening for the dropLocation property:

class Repainter extends PropertyChangeListener {
    public void propertyChange(PropertyChangeEvent pce) {
        repaintDropLocation(pce.getOldValue());
        repaintDropLocation(pce.getNewValue());
    }
}

comp.addPropertyChangeListener("dropLocation", newRepainter());

Here is an example of the paintComponent approach:

public void paintComponent(Graphics g) {
    super.paintComponent(g);

    DropLocation loc= getDropLocation();
    if (loc == null) {
        return;
    }

    renderPrettyIndicatorAt(loc);
}

Problems with the examples? Try Compiling and Running the Examples: FAQs.
Complaints? Compliments? Suggestions? Give us your feedback.

Previous page: Empty Table Drop
Next page: Top-Level Drop



Spec-Zone.ru - all specs in one place