Drag drop button and repaint

Where excatly in the code should I validate the parent,

In your event code, usually in the same place where you add or remove a component.

and who's parent?

The parent of the child component you are adding.

(the jButton's?)

Yes. Like this:

void jButton2_mouseClicked(MouseEvent e) {

botonquesedraga ani = new botonquesedraga();

this.add(ani, new XYConstraints(50,50,79,31));

this.validate();

///// SHOULD I VALIDATE IT HERE?Yes!

The validate method is a Container method and therefore can be used on AWT and

Swing containers. The revalidate method is a JComponent method and can be used on

Swing (up through j2se 1.5 anyway ?may apply to AWT someday). Validate whenever you make

changes to a containers children. It asks the container to do a new layout.

when I set a bakground and I drag a jButton, it leaves a shadow or a pintig bejind

where it was located before. Do you have any idea of how to avoid this rpobel

I'm not sure I understand exactly what you are doing. So I'll make up an example using

JLabels instead of JButtons. JButtons consume MouseEvents which is awkward for drag_n_drop

operations. Press the jButton2 to add a label to the centerPanel and then you can click

and drag the label. I've used a Swing/light-weight components for this. I'm not sure if

you would get the affect you mentioned if you used AWT/heavy-weight components. Otherwise,

I haven't a clue.

// <applet code="AppletpruebaRx" width="400" height="400"></applet>

import java.awt.*;

import java.awt.event.*;

import java.applet.*;

import javax.swing.*;

import javax.swing.event.MouseInputAdapter;

public class AppletpruebaRx extends Applet implements ActionListener {

private boolean isStandalone = false;

CenterPanel centerPanel;

public void init() {

try {

jbInit();

} catch(Exception e) {

e.printStackTrace();

}

}

private void jbInit() throws Exception {

JButton jButton2 = new JButton("jButton2");

jButton2.addActionListener(this);

JPanel south = new JPanel();

south.add(jButton2);

centerPanel = new CenterPanel();

setLayout(new BorderLayout());

add(centerPanel);

this.add(south, "Last");

}

public void actionPerformed(ActionEvent e) {

int count = centerPanel.getComponentCount();

JLabel label = new JLabel("Label " + (count+1), JLabel.CENTER);

label.setBorder(BorderFactory.createEtchedBorder());

centerPanel.add(label);

int x = count*50;

int y = count*50;

label.setBounds(x, y, 75, 30);

// Not needed for null layout but you might need

// this here for your Borland XYLayout.

//centerPanel.revalidate();

}

public String getParameter(String key, String def) {

return isStandalone ? System.getProperty(key, def) :

(getParameter(key) != null ? getParameter(key) : def);

}

public String getAppletInfo() { return "Applet Information"; }

public String[][] getParameterInfo() { return null; }

}

class CenterPanel extends JPanel {

public CenterPanel() {

super(null);

this.setBackground(new Color(0, 233, 216));

this.setForeground(Color.black);

PanelMouseAdapter adapter = new PanelMouseAdapter(this);

addMouseListener(adapter);

addMouseMotionListener(adapter);

}

public void setComponent(int index, int x, int y) {

Component c = getComponent(index);

c.setLocation(x, y);

repaint();

}

}

class PanelMouseAdapter extends MouseInputAdapter {

CenterPanel centerPanel;

Point offset = new Point();

int selectedIndex;

boolean dragging = false;

PanelMouseAdapter(CenterPanel cp) {

this.centerPanel = cp;

}

public void mousePressed(MouseEvent e) {

Point p = e.getPoint();

Component[] c = centerPanel.getComponents();

for(int j = 0; j < c.length; j++) {

Rectangle r = c[j].getBounds();

if(r.contains(p)) {

selectedIndex = j;

offset.x = p.x - r.x;

offset.y = p.y - r.y;

dragging = true;

break;

}

}

}

public void mouseReleased(MouseEvent e) {

dragging = false;

}

public void mouseDragged(MouseEvent e) {

if(dragging) {

int x = e.getX() - offset.x;

int y = e.getY() - offset.y;

centerPanel.setComponent(selectedIndex, x, y);

}

}

}

Message was edited by:

crwood

crwooda at 2007-7-12 20:36:09 >