dragjlabel.java

java实现的鼠标拖放的实现

package jdraganddropdemo;

import javax.swing.JLabel;
import java.awt.dnd.DragGestureEvent;
import java.awt.dnd.DragGestureListener;
import java.awt.dnd.*;
import java.awt.datatransfer.*;

class DragJLabel extends JLabel implements DragGestureListener, DragSourceListener {

  DragSource ds = DragSource.getDefaultDragSource();


  public DragJLabel(String title,int alignment){
    super(title,alignment);

    int action = DnDConstants.ACTION_COPY_OR_MOVE;
    ds.createDefaultDragGestureRecognizer(this,action,this);



  }
  public void dragGestureRecognized(DragGestureEvent dge) {
    /**@todo Implement this java.awt.dnd.DragGestureListener method*/
    //throw new java.lang.UnsupportedOperationException("Method dragGestureRecognized() not yet implemented.");
    try{
      Transferable tr = new StringSelection(this.getText());
      dge.startDrag(DragSource.DefaultCopyNoDrop,tr,this);
    }catch(Exception err){
      err.printStackTrace();
    }
  }
  public void dragEnter(DragSourceDragEvent dsde) {
    /**@todo Implement this java.awt.dnd.DragSourceListener method*/
    //throw new java.lang.UnsupportedOperationException("Method dragEnter() not yet implemented.");
    DragSourceContext dsc = dsde.getDragSourceContext();
    int action = dsde.getDropAction();
    if ((action&DnDConstants.ACTION_COPY)!=0)
      dsc.setCursor(DragSource.DefaultCopyDrop);
    else
      dsc.setCursor(DragSource.DefaultCopyNoDrop);
  }
  public void dragOver(DragSourceDragEvent dsde) {
    /**@todo Implement this java.awt.dnd.DragSourceListener method*/
    //throw new java.lang.UnsupportedOperationException("Method dragOver() not yet implemented.");
  }
  public void dropActionChanged(DragSourceDragEvent dsde) {
    /**@todo Implement this java.awt.dnd.DragSourceListener method*/
    //throw new java.lang.UnsupportedOperationException("Method dropActionChanged() not yet implemented.");
  }
  public void dragExit(DragSourceEvent dse) {
    /**@todo Implement this java.awt.dnd.DragSourceListener method*/
    //throw new java.lang.UnsupportedOperationException("Method dragExit() not yet implemented.");
  }
  public void dragDropEnd(DragSourceDropEvent dsde) {
    /**@todo Implement this java.awt.dnd.DragSourceListener method*/
    //throw new java.lang.UnsupportedOperationException("Method dragDropEnd() not yet implemented.");
    if (!dsde.getDropSuccess())
      return;
   // int action = dsde.getDropAction();
    //if ((action&DnDConstants.ACTION_MOVE)!=0)
     // this.setText("");
  }
}