Swap Component in JPanel
Hi there,
I have a JPanel that holds several Components (ThumbnailPanel ... own Class for Displaying Thumbs and Infos of a Pic). I want to have a function to sort this Panel. That means I have Arrow Buttons and can shift a ThumbPanel one to the left or to the right. I try to show you here (its better to understand if you see this):
http://www.rebelman.de/images/tpscreenshot.jpg
the arrows to sort are the small buttons in the upper right corner.
Logically the Components (ThumbnailPanels) are stored in a Vector and they are displayed in a JPanel with GridBagLayout. To shift a Component to the right, I have to swap it with its right neighbour. In the Vector its no problem
public void sortToRight() {
if(selIndex<currList.getImageCount()-2) {
//Vector swap
ImageData startImage = currList.getImage(selIndex);
ImageData swappedImage = currList.getImage(selIndex+1);
currList.setImage(selIndex, swappedImage);
currList.setImage(selIndex+1, startImage);
}But I cant swap the Components in the JPanel where they are displayed. I can get the reference to the component (panelName.getComponent(index)) ... but I cant set the reference e.g. panelName.setComponent(index, Component).
Any working idea? (I just think of swapping the constraint value of gridX ... but how? and does this work? The value for selIndex could point to the wrong component then and selection could run into trouble).
- Frankie
Edit: As mentioned in the last lines, I tried to swap the gridx Value:
Component startComponent = thumbScrollPanel.getComponent(selIndex);
Component swappedComponent = thumbScrollPanel.getComponent(selIndex+1);
GridBagConstraints startConstraints = panelLayout.getConstraints(startComponent);
GridBagConstraints swappedConstraints = panelLayout.getConstraints(swappedComponent);
int startX = startConstraints.gridx;
int swappedX = swappedConstraints.gridx;
startConstraints.gridx = swappedX;
swappedConstraints.gridx = startX;
thumbScrollPanel.validate();This does not work. The order, both Components are displayed is not changing.
Edited by: rebelman on Dec 13, 2007 1:14 AM
Maybe use a GridLayout so you don't have to worry about constraints.
Either way as mentioned above the key is to revalidate() the parent container after you add or remove a component from it. (Sometimes the repaint() is also necessary).
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import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.util.Vector;
import javax.swing.*;
import javax.swing.border.LineBorder;
import javax.swing.event.*;
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protected JLabel[] labels;
protected JPanel[] panels;
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int cx, cy;
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jp.setLayout(null);
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System.out.println("c.length = " + c.length);
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selectedJPanel = (JPanel)c[j];
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add(jp);
revalidate();
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setLayout(null);
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label3.setBounds( 125, 575, 125, 25);
label4.setBounds(425, 575, 125, 25);
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btn.setBounds(10, 5, 205, 25);
add(btn);
determineCenterOfComponents();
ComponentMover mover = new ComponentMover();
ActionListener lst = new ActionListener() {
public void actionPerformed(ActionEvent e) {
ComponentMover mover = new ComponentMover();
addMouseListener(mover);
addMouseMotionListener(mover);
btn.addActionListener(lst);
addMouseListener(ml);
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super.paintComponent(g);
Graphics2D g2 = (Graphics2D)g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON);
Point[] p;
g2.setStroke(new BasicStroke(4f));
for(int i = 0 ; i < order.size()-1; i++) {
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JPanel l2 = (JPanel)order.elementAt(i+1);
p = getCenterPoints(l1, l2);
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p2 = new Point();
Rectangle
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r2 = c2.getBounds();
p1.x = r1.x + r1.width/2;
p1.y = r1.y + r1.height/2;
p2.x = r2.x + r2.width/2;
p2.y = r2.y + r2.height/2;
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xMin = Integer.MAX_VALUE,
yMin = Integer.MAX_VALUE,
xMax = 0,
yMax = 0;
for(int i = 0; i < labels.length; i++)
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if(r.x < xMin)
xMin = r.x;
if(r.y < yMin)
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if(r.x + r.width > xMax)
xMax = r.x + r.width;
if(r.y + r.height > yMax)
yMax = r.y + r.height;
cx = xMin + (xMax - xMin)/2;
cy = yMin + (yMax - yMin)/2;
private class ComponentMover extends MouseInputAdapter
Point offsetP = new Point();
boolean dragging;
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for(int i = 0; i < panels.length; i++)
Rectangle r = panels[i].getBounds();
if(r.contains(p))
selectedJPanel = panels[i];
order.addElement(panels[i]);
offsetP.x = p.x - r.x;
offsetP.y = p.y - r.y;
dragging = true;
repaint(); //added
break;
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dragging = false;
public void mouseDragged(MouseEvent e)
if(dragging)
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r.x = e.getX() - offsetP.x;
r.y = e.getY() - offsetP.y;
selectedJPanel.setBounds(r.x, r.y, r.width, r.height);
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label1 = new JLabel("Label 1");
label2 = new JLabel("Label 2");
label3 = new JLabel("Label 3");
label4 = new JLabel("Label 4");
labels = new JLabel[] {
label1, label2, label3, label4
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import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;
import javax.swing.event.MouseInputAdapter;
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public Resizing() {
super(null);
addPanel();
PanelControlAdapter control = new PanelControlAdapter(this);
addMouseListener(control);
addMouseMotionListener(control);
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JLabel jl = new JLabel("This is resizeable JPanel at Runtime");
jl.setBackground(Color.green);
jl.setOpaque(true);
jl.setFont(new Font("Helvetica", Font.BOLD, 18));
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jp.setLayout(new BorderLayout());
jp.setBorder(new LineBorder(Color.black, 3, false));
jp.add(jl, BorderLayout.NORTH);
jp.setBounds(50,50,400,200);
add(jp);
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f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.getContentPane().add(new Resizing());
f.setSize(500,400);
f.setLocation(100,100);
f.setVisible(true);
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Resizing host;
Component selectedComponent;
LineBorder black;
LineBorder green;
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Point start = new Point();
boolean dragging = false;
boolean resizing = false;
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host = r;
black = new LineBorder(Color.black, 3, false);
green = new LineBorder(Color.green, 3, false);
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Point p = e.getPoint();
boolean hovering = false;
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((JComponent)selectedComponent).setBorder(black);
selectedComponent = c;
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break;
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cursor = Cursor.getPredefinedCursor(Cursor.NW_RESIZE_CURSOR);
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cursor = Cursor.getPredefinedCursor(Cursor.W_RESIZE_CURSOR);
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cursor = Cursor.getPredefinedCursor(Cursor.SW_RESIZE_CURSOR);
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cursor = Cursor.getPredefinedCursor(Cursor.S_RESIZE_CURSOR);
break;
case Rectangle.OUT_BOTTOM + Rectangle.OUT_RIGHT:
cursor = Cursor.getPredefinedCursor(Cursor.SE_RESIZE_CURSOR);
break;
case Rectangle.OUT_RIGHT:
cursor = Cursor.getPredefinedCursor(Cursor.E_RESIZE_CURSOR);
break;
case Rectangle.OUT_RIGHT + Rectangle.OUT_TOP:
cursor = Cursor.getPredefinedCursor(Cursor.NE_RESIZE_CURSOR);
break;
default:
cursor = Cursor.getDefaultCursor();
selectedComponent.setCursor(cursor);
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Point p = e.getPoint();
if(selectedComponent != null) {
Rectangle r = selectedComponent.getBounds();
if(selectedComponent.getCursor() == Cursor.getDefaultCursor()) {
offset.x = p.x - r.x;
offset.y = p.y - r.y;
dragging = true;
} else {
start = p;
resizing = true;
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dragging = false;
resizing = false;
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Point p = e.getPoint();
if(dragging || resizing) {
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if(dragging) {
r.x = p.x - offset.x;
r.y = p.y - offset.y;
selectedComponent.setLocation(r.x, r.y);
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int type = selectedComponent.getCursor().getType();
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r.y = p.y;
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r.width -= p.x - start.x;
r.x = p.x;
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break;
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r.height += p.y - start.y;
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r.width += p.x - start.x;
r.height += p.y - start.y;
break;
case Cursor.E_RESIZE_CURSOR:
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r.width += p.x - start.x;
r.height -= p.y - start.y;
r.y = p.y;
break;
default:
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Hi
I'm creating a MultiComboBox component made up of a variable number of combo boxes. It's essentially a way for the user to select from a list, then a sub-selection list (then, if appropriate, a sub-sub-selection list etc) until a final selection is made. A sort of category hierarchy thing.
Anyway, I've got it working, but it's bothering me that the layout (I'm currently using a grid layout) and the border are currently hard-coded in the constructor of the MultiComboBox. This seems to be the way that most custom components are created, although my MultiComboBox could easily work with a number of different layouts, so I'm thinking there must be a better way that would enable the user of the component to set their own layout and border. Is there an effective standard approach for going about this? I'm thinking I should be overriding a few methods of Component / JComponent / JPanel (which my MultiComboBox currently extends), like the getLayout(), getBorder(), so that they either return my default layout, or a layout the user has set with setLayout(). But then would I need to call validate() or something, and where should I be creating my array of combo boxes (currently I'm doing this in the constructor)?
Any advice appreciated
MartinHm ...
I use JTree for example to organize my application - say it is a kind of alternative menu and organizing system. It is a simple to use and very flexible component if you really have studied, how view, model and controller are working together - each of them can be manipulated or even replaced.
The whole swing architecture is highly reconfigurable - I like it's design very much even so you have to struggle with it when you start using swing components for the first time :) - a very important point is to understand the event handling of the components - some people don't study that and struggle with invalidate() revalidate() and repaint() what is not needed at all, if you have understood which event to fire from which object :)
greetings Marsian
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