Java Tips - How to detect a drag initiating gesture in your application

This Java Swing tip illustrates a method of detecting a drag initiating gesture in your application. The tip demonstrates a simple test of the DragGesture classes to see if we can recognize a simple drag gesture. Developers may use this gesture to execute different functionalities.


import java.awt.*;

import java.awt.dnd.*;

import java.awt.datatransfer.*;

import java.awt.event.*;

import java.io.*;

import java.util.*;

import javax.swing.*;



public class GestureTest extends JFrame implements DragGestureListener {



  DragSource ds;

  JList jl;

  String[] items = {"Java", "C", "C++", "Lisp", "Perl", "Python"};



  public GestureTest() {

    super("Gesture Test");

    setSize(200,150);

    addWindowListener(new WindowAdapter() {

      public void windowClosing(WindowEvent we) {

        System.exit(0);

      }

    });

    jl = new JList(items);

    jl.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);

    getContentPane().add(new JScrollPane(jl), BorderLayout.CENTER);



    ds = new DragSource();

    DragGestureRecognizer dgr = ds.createDefaultDragGestureRecognizer(

        jl, DnDConstants.ACTION_COPY, this);

    setVisible(true);

  }



  public void dragGestureRecognized(DragGestureEvent dge) {

    System.out.println("Drag Gesture Recognized!");

  }



  public static void main(String args[]) {

    new GestureTest();

  }

}

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