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-rw-r--r--java/awt/dnd/DropTarget.java124
1 files changed, 103 insertions, 21 deletions
diff --git a/java/awt/dnd/DropTarget.java b/java/awt/dnd/DropTarget.java
index 1e7b2c4cd..63be5ac04 100644
--- a/java/awt/dnd/DropTarget.java
+++ b/java/awt/dnd/DropTarget.java
@@ -38,12 +38,12 @@ exception statement from your version. */
package java.awt.dnd;
-import gnu.classpath.NotImplementedException;
-
import java.awt.Component;
import java.awt.GraphicsEnvironment;
import java.awt.HeadlessException;
+import java.awt.Insets;
import java.awt.Point;
+import java.awt.Rectangle;
import java.awt.datatransfer.FlavorMap;
import java.awt.datatransfer.SystemFlavorMap;
import java.awt.dnd.peer.DropTargetPeer;
@@ -55,6 +55,8 @@ import java.io.Serializable;
import java.util.EventListener;
import java.util.TooManyListenersException;
+import javax.swing.Timer;
+
/**
* @author Michael Koch
* @since 1.2
@@ -70,30 +72,87 @@ public class DropTarget
protected static class DropTargetAutoScroller
implements ActionListener
{
+ /**
+ * The threshold that keeps the autoscroller running.
+ */
+ private static final int HYSTERESIS = 10;
+
+ /**
+ * The initial timer delay.
+ */
+ private static final int DELAY = 100;
+
private Component component;
private Point point;
-
+
+ /**
+ * The timer that triggers autoscrolling.
+ */
+ private Timer timer;
+
+ /**
+ * The outer region of the scroller. This is the component's size.
+ */
+ private Rectangle outer;
+
+ /**
+ * The inner region of the scroller. This is the component size without
+ * the autoscroll insets.
+ */
+ private Rectangle inner;
+
protected DropTargetAutoScroller (Component c, Point p)
{
component = c;
point = p;
+ timer = new Timer(DELAY, this);
+ timer.setCoalesce(true);
+ timer.start();
}
protected void updateLocation (Point newLocn)
{
+ Point previous = point;
point = newLocn;
+ if (Math.abs(point.x - previous.x) > HYSTERESIS
+ || Math.abs(point.y - previous.y) > HYSTERESIS)
+ {
+ if (timer.isRunning())
+ timer.stop();
+ }
+ else
+ {
+ if (! timer.isRunning())
+ timer.start();
+ }
}
protected void stop ()
- throws NotImplementedException
{
- // FIXME: implement this
+ timer.start();
}
public void actionPerformed (ActionEvent e)
- throws NotImplementedException
{
- // FIXME: implement this
+ Autoscroll autoScroll = (Autoscroll) component;
+
+ // First synchronize the inner and outer rectangles.
+ Insets i = autoScroll.getAutoscrollInsets();
+ int width = component.getWidth();
+ int height = component.getHeight();
+ if (width != outer.width || height != outer.height)
+ outer.setBounds(0, 0, width, height);
+ if (inner.x != i.left || inner.y != i.top)
+ inner.setLocation(i.left, i.top);
+ int inWidth = width - i.left - i.right;
+ int inHeight = height - i.top - i.bottom;
+ if (inWidth != inner.width || inHeight != inner.height)
+ inner.setSize(inWidth, inHeight);
+
+ // Scroll if the outer rectangle contains the location, but the
+ // inner doesn't.
+ if (outer.contains(point) && ! inner.contains(point))
+ autoScroll.autoscroll(point);
}
}
@@ -182,6 +241,8 @@ public class DropTarget
*/
public void setComponent (Component c)
{
+ if (component != null)
+ clearAutoscroll();
component = c;
}
@@ -212,6 +273,8 @@ public class DropTarget
public void setActive (boolean active)
{
this.active = active;
+ if (! active)
+ clearAutoscroll();
}
public boolean isActive()
@@ -250,30 +313,47 @@ public class DropTarget
public void dragEnter(DropTargetDragEvent dtde)
{
- if (dropTargetListener != null)
- dropTargetListener.dragEnter(dtde);
+ if (active)
+ {
+ if (dropTargetListener != null)
+ dropTargetListener.dragEnter(dtde);
+ initializeAutoscrolling(dtde.getLocation());
+ }
}
public void dragOver(DropTargetDragEvent dtde)
{
- if (dropTargetListener != null)
- dropTargetListener.dragOver(dtde);
+ if (active)
+ {
+ if (dropTargetListener != null)
+ dropTargetListener.dragOver(dtde);
+ updateAutoscroll(dtde.getLocation());
+ }
}
public void dropActionChanged(DropTargetDragEvent dtde)
{
- if (dropTargetListener != null)
- dropTargetListener.dropActionChanged(dtde);
+ if (active)
+ {
+ if (dropTargetListener != null)
+ dropTargetListener.dropActionChanged(dtde);
+ updateAutoscroll(dtde.getLocation());
+ }
}
public void dragExit(DropTargetEvent dte)
{
- if (dropTargetListener != null)
- dropTargetListener.dragExit(dte);
+ if (active)
+ {
+ if (dropTargetListener != null)
+ dropTargetListener.dragExit(dte);
+ clearAutoscroll();
+ }
}
public void drop(DropTargetDropEvent dtde)
{
+ clearAutoscroll();
if (dropTargetListener != null)
dropTargetListener.drop(dtde);
}
@@ -332,15 +412,13 @@ public class DropTarget
protected DropTarget.DropTargetAutoScroller createDropTargetAutoScroller
(Component c, Point p)
{
- if (autoscroller == null)
- autoscroller = new DropTarget.DropTargetAutoScroller (c, p);
-
- return autoscroller;
+ return new DropTarget.DropTargetAutoScroller (c, p);
}
protected void initializeAutoscrolling(Point p)
{
- createDropTargetAutoScroller (component, p);
+ if (component instanceof Autoscroll) // Checks for null too.
+ autoscroller = createDropTargetAutoScroller (component, p);
}
protected void updateAutoscroll(Point dragCursorLocn)
@@ -351,6 +429,10 @@ public class DropTarget
protected void clearAutoscroll()
{
- autoscroller = null;
+ if (autoscroller != null)
+ {
+ autoscroller.stop();
+ autoscroller = null;
+ }
}
} // class DropTarget