Re: Drag two images with a mouse anywhere in the frame

bH <>
Tue, 22 Mar 2011 07:38:12 -0700 (PDT)
On Mar 21, 7:48 am, "John B. Matthews" <nos...@nospam.invalid> wrote:

In article <im66uv$>,
 Daniele Futtorovic <da.futt.n...@laposte-dot-net.invalid> wrote:

On 21/03/2011 00:42, bH allegedly wrote:

Hi All, I need a java application/applet program that will load two
images in one frame. I should also be able to drag each image
independently with the mouse within that one frame. Where I drag
the images to will be independent and thus the placement of each
image will not have preset locations available. I already have a
java program where images can be moved with the mouse to a open,
preset locations.

I have searched for demos. I find that there are none. Perhaps I
didn't word the search phrase correctly. For instance "java demo
'move two images with a mouse.'"

How about a layered layout? Put your images in a JLabel on some
different layers, then attach a simple MouseListener to each of the
labels, store the mouse position (careful whether it's absolute or
relative) on MOUSE_DOWN, compare to the position on MOUSE_UP, do a
diff and setBounds, possibly with some sandboxing. Or implement
mouseDragged and do the diffs in real-time.

bH: Let me endorse DF's suggestion. Here's one of my favorite examples
of using JLayeredPane in this way:


As an alternative, JInternalFrame is also worth a look:


John B. Matthews
trashgod at gmail dot com
<>- Hide quoted text -

- Show quoted text -

Hi Daniele and John,
A big "THANKS" for your replies.
The program below takes 3 images
allows for showing them in random order
at random locations. The user then uses the mouse to
move the images to reorder. It is a work in progress.
I have not studied the entire list of your
recommendations but eventually hope to do so.

I appreciate your responses very much.

/* original:
 * Version2: 22 March 2011:
 * Three XX.png images stored in folder named "images"
 * The program takes the images puts them in random order
 * at random locations. The user then uses the mouse to
 * move the images to reorder. bH
import java.awt.EventQueue;
import java.awt.Container;
import java.awt.Component;
import java.awt.GridLayout;

import java.awt.event. MouseListener;
import java.awt.event.MouseMotionListener;
import java.awt.event.MouseEvent;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Random;

import javax.swing.JFrame;
import javax.swing. JLayeredPane;
import javax.swing.ImageIcon;
import javax.swing.JLabel;

public class LabelDragAndDropVer2 extends JFrame implements
    MouseListener, MouseMotionListener
    JLayeredPane layeredPane;
    Component dragComponent;
    int xAdjustment;
    int yAdjustment;
    private String strNumber[] = new String [3];
    private int number = 0 ;

    private Random wheel = new Random();
    int high= 60;
    int low = 20;
    int numPictures = 3;

    // two arrays stores x,y values
    int[] xPoints = new int[numPictures];
    int[] yPoints = new int[numPictures];

    public LabelDragAndDropVer2() {

    public void init() {
    // Use a Layered Pane for this this application
        layeredPane = new JLayeredPane();
        layeredPane.setLayout( null );
        layeredPane.addMouseListener( this );
        layeredPane.addMouseMotionListener( this );

        // ordering the location of picture random
        for (int i= 0;i <numPictures; i++){
            int m = wheel.nextInt(high - low + 1 ) + low;
            xPoints[i]= m;
            int n = wheel.nextInt(high - low + 1 ) + low;
            yPoints[i]= n;
            System.out.println(i+ " "+ m + " ," + n);

        for(int i = 0; i<3; i++){
            strNumber[i] = Integer.toString(i);
            number = Integer.parseInt(strNumber[i]);
        // ordering the images randomly
        List<String> inputList = Arrays.asList(strNumber);

        for (int i= 0;i <3; i++){
            number = Integer.parseInt(strNumber[i]);
            ImageIcon julia = new ImageIcon("images/MH"+
                                            number + ".png");
            JLabel label = new JLabel(julia);
            label.setLocation(xPoints[i], yPoints[i]);
            label.setSize( label.getPreferredSize() );

        Container contentPane= getContentPane();
        contentPane.setLayout(new GridLayout(1,2) );
        setSize(600,600);// frame size
     ** Determine if we clicked on a moveable component
    public void mousePressed(MouseEvent e)
        dragComponent = null;
        Component c = layeredPane.findComponentAt(e.getX(),
        if (c instanceof JLayeredPane) return;
        dragComponent = c;
        xAdjustment = dragComponent.getLocation().x - e.getX();
        yAdjustment = dragComponent.getLocation().y - e.getY();
        dragComponent.setLocation(e.getX() + xAdjustment,
                                  e.getY() + yAdjustment);
     ** Move the component around the panel
    public void mouseDragged(MouseEvent me)
        if (dragComponent == null) return;
        dragComponent.setLocation(me.getX() + xAdjustment,
                                  me.getY() + yAdjustment);
     ** Deselect the component
    public void mouseReleased(MouseEvent e)
        dragComponent = null;
    public void mouseClicked(MouseEvent e) {}
    public void mouseMoved(MouseEvent e) {}
    public void mouseEntered(MouseEvent e) {}
    public void mouseExited(MouseEvent e) {}

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                new LabelDragAndDropVer2();

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