- 1 year ago
Java drag cursor not changing under Windows
If you're facing an issue where the cursor doesn't change when dragging in a Java application on Windows, it could be due to the default behavior of the DragSource
in Java. By default, the DragSource
uses a default cursor during drag operations, which might not change to the expected cursor.
To change the cursor during a drag operation in a Java application on Windows, you can implement a custom DragSourceListener
and set the desired cursor manually. Here's an example:
javaimport java.awt.*;
import java.awt.datatransfer.*;
import java.awt.dnd.*;
public class CustomDragSourceListener implements DragSourceListener {
private Cursor dragCursor;
public CustomDragSourceListener() {
// Set the desired drag cursor
dragCursor = Cursor.getPredefinedCursor(Cursor.MOVE_CURSOR);
}
@Override
public void dragEnter(DragSourceDragEvent dsde) {
dsde.getDragSourceContext().setCursor(dragCursor);
}
@Override
public void dragExit(DragSourceEvent dse) {
dse.getDragSourceContext().setCursor(DragSource.DefaultMoveNoDrop);
}
@Override
public void dragOver(DragSourceDragEvent dsde) {
// No action needed
}
@Override
public void dropActionChanged(DragSourceDragEvent dsde) {
// No action needed
}
@Override
public void dragDropEnd(DragSourceDropEvent dsde) {
// No action needed
}
}
In the above example, we implement the DragSourceListener
interface and set the desired drag cursor in the constructor (Cursor.MOVE_CURSOR
in this case). We then override the dragEnter
method and set the custom cursor using DragSourceContext#setCursor
.
To use this custom drag source listener in your application, you'll need to create a DragSource
and associate it with the component that supports dragging. Here's an example:
javaimport javax.swing.*;
import java.awt.*;
import java.awt.datatransfer.*;
import java.awt.dnd.*;
public class DragExample {
public static void main(String[] args) {
JFrame frame = new JFrame("Drag Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JLabel label = new JLabel("Drag me");
label.setTransferHandler(new TransferHandler("text"));
DragSource dragSource = DragSource.getDefaultDragSource();
dragSource.createDefaultDragGestureRecognizer(
label, DnDConstants.ACTION_COPY_OR_MOVE, new DragGestureListener() {
@Override
public void dragGestureRecognized(DragGestureEvent dge) {
Cursor cursor = Cursor.getPredefinedCursor(Cursor.MOVE_CURSOR);
dge.startDrag(cursor, new StringSelection("Hello World"),
new CustomDragSourceListener());
}
});
frame.getContentPane().add(label);
frame.setSize(200, 200);
frame.setVisible(true);
}
}
In the above example, we create a DragSource
and associate it with the JLabel
component using DragSource#createDefaultDragGestureRecognizer
. We pass an implementation of DragGestureListener
to the method, where we set the desired cursor for the drag operation (Cursor.MOVE_CURSOR
) and use the custom DragSourceListener
(CustomDragSourceListener
).
With this implementation, the cursor will change to the desired cursor during a drag operation in a Java application on Windows.
Note: The above examples use the AWT and Swing libraries for simplicity. If you are using a different UI framework or library, the approach might vary slightly, but the general idea remains the same: implement a custom `DragSourceListener