Develop Reference

Too many JPanels inside a JPanel (with GridBagLayout)

So basically if I put JPanels inside a JPanel that uses GridBagLayout and I restrict the size with setPreferredSize, eventually it reaches a point where it can't hold all of them, and it exhibits the behavior shown in the attached picture:
I'm making an accordion. This is just an example to showcase the problem I'm having. Each part of the accordion can open individually and they're of arbitrary size and get added on the fly. Its easy enough to get the heights of all the individual panels and compare them against the total height, but when too many are added it exhibits the crunching behavior I've shown. This also shrinks the heights so its much more difficult to determine when the crunching has happened. I would have to cache heights and somehow pre-calculate the heights of the new parts getting added. The end goal is to remove older panels when a new panel is added and there isn't enough room for it.
Is there an easy way to determine what height something would be if it weren't constrained, or maybe a supported way to detect when such crunching has is happening (so I can quickly thin it out before it gets painted again)? An option that makes GridBagLayout behave like some other layouts and overflow into hammerspace instead of compressing would work too.
Code for example:
import java.awt.*;
import java.awt.event.*;
import javaisms.out;
import javax.swing.*;
public class FoldDrag extends JLayeredPane {
public TexturedPanel backingPanel = new TexturedPanel(new GridBagLayout(),"data/gui/grayerbricks.png");
static JPanel windowbase=new JPanel();
static JPanel restrictedpanel=new JPanel(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
public FoldDrag() {
JButton addpan = new JButton("Add things");
windowbase.add(addpan);
windowbase.add(restrictedpanel);
restrictedpanel.setBackground(Color.red);
restrictedpanel.setPreferredSize(new Dimension(200,200));
gbc.weighty=1;
gbc.weightx=1;
gbc.gridx=0;
gbc.gridy=0;
gbc.gridheight=1;
gbc.gridwidth=1;
gbc.fill=GridBagConstraints.HORIZONTAL;
addpan.addActionListener(new ActionListener() {
int number=0;
#Override
public void actionPerformed(ActionEvent e)
{
number++;
gbc.gridy=number;
JPanel tmppanel = new JPanel();
tmppanel.setPreferredSize(new Dimension(100,30));
if(number%3==0)
tmppanel.setBackground(Color.blue);
if(number%3==1)
tmppanel.setBackground(Color.yellow);
if(number%3==2)
tmppanel.setBackground(Color.green);
restrictedpanel.add(tmppanel,gbc);
restrictedpanel.validate();
}
});
windowbase.setVisible(true);
}
private static void createAndShowUI() {
JFrame frame = new JFrame("DragLabelOnLayeredPane");
frame.getContentPane().add(windowbase);
FoldDrag thedrag=new FoldDrag();
windowbase.add(thedrag);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setPreferredSize(new Dimension(300,300));
frame.pack();
frame.setResizable(true);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
out.active=true;
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
createAndShowUI();
}
});
}
}
EDIT: Seems I didn't describe my version of the accordion very well. Here's a link.

You have particular requirement which may be better served through the use of it's layout manager. This provides you the ability to control every aspect of the layout without the need to resort to hacks or "work arounds" which never quite work or have bizarre side effects
public class AccordionLayout implements LayoutManager {
// This "could" be controlled by constraints, but that would assume
// that more then one component could be expanded at a time
private Component expanded;
public void setExpanded(Component expanded) {
this.expanded = expanded;
}
public Component getExpanded() {
return expanded;
}
#Override
public void addLayoutComponent(String name, Component comp) {
}
#Override
public void removeLayoutComponent(Component comp) {
}
#Override
public Dimension preferredLayoutSize(Container parent) {
Dimension size = minimumLayoutSize(parent);
if (expanded != null) {
size.height -= expanded.getMinimumSize().height;
size.height += expanded.getPreferredSize().height;
}
return size;
}
#Override
public Dimension minimumLayoutSize(Container parent) {
int height = 0;
int width = 0;
for (Component comp : parent.getComponents()) {
width = Math.max(width, comp.getPreferredSize().width);
height += comp.getMinimumSize().height;
}
return new Dimension(width, height);
}
#Override
public void layoutContainer(Container parent) {
Insets insets = parent.getInsets();
int availableHeight = parent.getHeight() - (insets.top + insets.bottom);
int x = insets.left;
int y = insets.top;
int maxSize = 0;
Dimension minSize = minimumLayoutSize(parent);
if (expanded != null) {
minSize.height -= expanded.getMinimumSize().height;
// Try an honour the preferred size the expanded component...
maxSize = Math.max(expanded.getPreferredSize().height, availableHeight - minSize.height);
}
int width = parent.getWidth() - (insets.left + insets.right);
for (Component comp : parent.getComponents()) {
if (expanded != comp) {
comp.setSize(width, comp.getMinimumSize().height);
} else {
comp.setSize(width, maxSize);
}
comp.setLocation(x, y);
y += comp.getHeight();
}
}
}
And the runnable example...
This goes to the enth degree, creating a specialised component to act as each "fold", but this just reduces the complexity of the API from the outside, meaning, you just need to think about the title and the content and let the rest of the API take care of itself
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.FlowLayout;
import java.awt.Insets;
import java.awt.LayoutManager;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.border.LineBorder;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private AccordionLayout layout;
public TestPane() {
layout = new AccordionLayout();
setLayout(layout);
AccordionListener listener = new AccordionListener() {
#Override
public void accordionSelected(Component comp) {
layout.setExpanded(comp);
revalidate();
repaint();
}
};
Color colors[] = {Color.RED, Color.BLUE, Color.CYAN, Color.GREEN, Color.MAGENTA, Color.ORANGE, Color.PINK, Color.YELLOW};
String titles[] = {"Red", "Blue", "Cyan", "Green", "Magenta", "Orange", "Pink", "Yellow"};
for (int index = 0; index < colors.length; index++) {
AccordionPanel panel = new AccordionPanel(titles[index], new ContentPane(colors[index]));
panel.setAccordionListener(listener);
add(panel);
}
}
}
public class ContentPane extends JPanel {
public ContentPane(Color background) {
setBackground(background);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(100, 100);
}
}
public interface AccordionListener {
public void accordionSelected(Component comp);
}
public class AccordionPanel extends JPanel {
private JLabel title;
private JPanel header;
private Component content;
private AccordionListener accordionListener;
public AccordionPanel() {
setLayout(new BorderLayout());
title = new JLabel("Title");
header = new JPanel(new FlowLayout(FlowLayout.LEADING));
header.setBackground(Color.GRAY);
header.setBorder(new LineBorder(Color.BLACK));
header.add(title);
add(header, BorderLayout.NORTH);
header.addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
AccordionListener listener = getAccordionListener();
if (listener != null) {
listener.accordionSelected(AccordionPanel.this);
}
}
});
}
public AccordionPanel(String title) {
this();
setTitle(title);
}
public AccordionPanel(String title, Component content) {
this(title);
setContentPane(content);
}
public void setAccordionListener(AccordionListener accordionListener) {
this.accordionListener = accordionListener;
}
public AccordionListener getAccordionListener() {
return accordionListener;
}
public void setTitle(String text) {
title.setText(text);
revalidate();
}
public String getText() {
return title.getText();
}
public void setContentPane(Component content) {
if (this.content != null) {
remove(this.content);
}
this.content = content;
if (this.content != null) {
add(this.content);
}
revalidate();
}
public Component getContent() {
return content;
}
#Override
public Dimension getMinimumSize() {
return header.getPreferredSize();
}
#Override
public Dimension getPreferredSize() {
Dimension size = content != null ? content.getPreferredSize() : super.getPreferredSize();
Dimension min = getMinimumSize();
size.width = Math.max(min.width, size.width);
size.height += min.height;
return size;
}
}
public class AccordionLayout implements LayoutManager {
// This "could" be controled by constraints, but that would assume
// that more then one component could be expanded at a time
private Component expanded;
public void setExpanded(Component expanded) {
this.expanded = expanded;
}
public Component getExpanded() {
return expanded;
}
#Override
public void addLayoutComponent(String name, Component comp) {
}
#Override
public void removeLayoutComponent(Component comp) {
}
#Override
public Dimension preferredLayoutSize(Container parent) {
Dimension size = minimumLayoutSize(parent);
if (expanded != null) {
size.height -= expanded.getMinimumSize().height;
size.height += expanded.getPreferredSize().height;
}
return size;
}
#Override
public Dimension minimumLayoutSize(Container parent) {
int height = 0;
int width = 0;
for (Component comp : parent.getComponents()) {
width = Math.max(width, comp.getPreferredSize().width);
height += comp.getMinimumSize().height;
}
return new Dimension(width, height);
}
#Override
public void layoutContainer(Container parent) {
Insets insets = parent.getInsets();
int availableHeight = parent.getHeight() - (insets.top + insets.bottom);
int x = insets.left;
int y = insets.top;
int maxSize = 0;
Dimension minSize = minimumLayoutSize(parent);
if (expanded != null) {
minSize.height -= expanded.getMinimumSize().height;
// Try an honour the preferred size the expanded component...
maxSize = Math.max(expanded.getPreferredSize().height, availableHeight - minSize.height);
}
int width = parent.getWidth() - (insets.left + insets.right);
for (Component comp : parent.getComponents()) {
if (expanded != comp) {
comp.setSize(width, comp.getMinimumSize().height);
} else {
comp.setSize(width, maxSize);
}
comp.setLocation(x, y);
y += comp.getHeight();
}
}
}
}
Now, if you're really up for a challenge, you could use something a animated layout proxy and do something like...

The end goal is to remove older panels when a new panel is added and there isn't enough room for it
I would guess that after you add a panel you compare the preferred height with the actual height. When the preferred height is greater you have a problem and you remove components as required.
So then the next problem is to use a layout manager that doesn't change the heights of the panels. This can still be done with the GridBagLayout. You just need to override the getMinimumSize() method to return the getPreferredSize() Dimension.
Each part of the accordion can open individually and they're of arbitrary size and get added on the fly
You might want to consider using the Relative Layout. You can add components whose preferred size will be respected. So you will be able to check when the preferred height is greater than the actual height.
Then you can also add components that will be sized based on the amount of space left in the panel. These would be your expanding panels.
So in your example you example when you expand an item you could configure that component to take up the entire space available. If you expand two items then they would each get half the space available.
Maybe something like this:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class ExpandingPanel extends JPanel
{
private JPanel expanding;
public ExpandingPanel(String text, Color color)
{
setLayout( new BorderLayout() );
JButton button = new JButton( text );
add(button, BorderLayout.NORTH);
expanding = new JPanel();
expanding.setBackground( color );
expanding.setVisible( false );
add(expanding, BorderLayout.CENTER);
button.addActionListener( new ActionListener()
{
#Override
public void actionPerformed(ActionEvent e)
{
expanding.setVisible( !expanding.isVisible() );
Container parent = ExpandingPanel.this.getParent();
LayoutManager2 layout = (LayoutManager2)parent.getLayout();
if (expanding.isVisible())
layout.addLayoutComponent(ExpandingPanel.this, new Float(1));
else
layout.addLayoutComponent(ExpandingPanel.this, null);
revalidate();
repaint();
}
});
}
private static void createAndShowGUI()
{
RelativeLayout rl = new RelativeLayout(RelativeLayout.Y_AXIS);
rl.setFill( true );
JPanel content = new JPanel( rl );
content.add( new ExpandingPanel("Red", Color.RED) );
content.add( new ExpandingPanel("Blue", Color.BLUE) );
content.add( new ExpandingPanel("Green", Color.GREEN) );
JFrame frame = new JFrame("Expanding Panel");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add( content);
frame.setLocationByPlatform( true );
frame.setSize(200, 300);
frame.setVisible( true );
}
public static void main(String[] args)
{
EventQueue.invokeLater(new Runnable()
{
public void run()
{
createAndShowGUI();
}
});
}
}

You can tell something is "crunched" when panel.getPreferredSize().height != panel.getHeight() and panel.getPreferredSize().width != panel.getWidth()

Java transparent panels & custom effect on panels

I want to have transparent panels in my GUI (if like Windows 7 window headers, it is better).
Before I have used com.sun.awt.AWTUtilities as
AWTUtilities.setWindowOpacity(frame, (float)0.90);
but its parameter is a window like JFrame and couldn't be used for JPanel.
Also I want to have effects on JPanel or JLabel for example luminescence, as is on Windows 7 header buttons. Any other interesting effect is also helpful for me.

Please see the tutorials How to Create Translucent and Shaped Windows and* How to Create Translucent and Shaped Windows*. Follow the links to excellent example depots by #camickr.
For example,
import java.awt.event.*;
import java.awt.Color;
import java.awt.AlphaComposite;
import javax.swing.*;
import javax.swing.UIManager.LookAndFeelInfo;
public class ButtonTest {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new ButtonTest().createAndShowGUI();
}
});
}
private JFrame frame;
private JButton opaqueButton1;
private JButton opaqueButton2;
private SoftJButton softButton1;
private SoftJButton softButton2;
public void createAndShowGUI() {
opaqueButton1 = new JButton("Opaque Button");
opaqueButton2 = new JButton("Opaque Button");
softButton1 = new SoftJButton("Transparent Button");
softButton2 = new SoftJButton("Transparent Button");
opaqueButton1.setBackground(Color.GREEN);
softButton1.setBackground(Color.GREEN);
frame = new JFrame();
frame.getContentPane().setLayout(new java.awt.GridLayout(2, 2, 10, 10));
frame.add(opaqueButton1);
frame.add(softButton1);
frame.add(opaqueButton2);
frame.add(softButton2);
frame.setSize(567, 350);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
Timer alphaChanger = new Timer(30, new ActionListener() {
private float incrementer = -.03f;
#Override
public void actionPerformed(ActionEvent e) {
float newAlpha = softButton1.getAlpha() + incrementer;
if (newAlpha < 0) {
newAlpha = 0;
incrementer = -incrementer;
} else if (newAlpha > 1f) {
newAlpha = 1f;
incrementer = -incrementer;
}
softButton1.setAlpha(newAlpha);
softButton2.setAlpha(newAlpha);
}
});
alphaChanger.start();
Timer uiChanger = new Timer(3500, new ActionListener() {
private LookAndFeelInfo[] laf = UIManager.getInstalledLookAndFeels();
private int index = 1;
#Override
public void actionPerformed(ActionEvent e) {
try {
UIManager.setLookAndFeel(laf[index].getClassName());
SwingUtilities.updateComponentTreeUI(frame);
} catch (Exception exc) {
exc.printStackTrace();
}
index = (index + 1) % laf.length;
}
});
uiChanger.start();
}
public static class SoftJButton extends JButton {
private static final JButton lafDeterminer = new JButton();
private static final long serialVersionUID = 1L;
private boolean rectangularLAF;
private float alpha = 1f;
public SoftJButton() {
this(null, null);
}
public SoftJButton(String text) {
this(text, null);
}
public SoftJButton(String text, Icon icon) {
super(text, icon);
setOpaque(false);
setFocusPainted(false);
}
public float getAlpha() {
return alpha;
}
public void setAlpha(float alpha) {
this.alpha = alpha;
repaint();
}
#Override
public void paintComponent(java.awt.Graphics g) {
java.awt.Graphics2D g2 = (java.awt.Graphics2D) g;
g2.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, alpha));
if (rectangularLAF && isBackgroundSet()) {
Color c = getBackground();
g2.setColor(c);
g.fillRect(0, 0, getWidth(), getHeight());
}
super.paintComponent(g2);
}
#Override
public void updateUI() {
super.updateUI();
lafDeterminer.updateUI();
rectangularLAF = lafDeterminer.isOpaque();
}
}
}

If you have time I recommend you go through this Filty Rich Clients. By using this book you can learn to create stunning visual and animated effects with Swing and Java 2D. Learn graphics and animation fundamentals as well as advanced rendering techniques.
EDIT:
To creat transparent panels call
setOpaque(false)
It'll pass off painting the background to its parent, which may draw its own background.
You can do a screen capture and then use that to paint the background of the panel.

allowing users to "draw" and resize JTextArea

I want to allow users to be able to "draw" with their mouse (click and drag) to create and size a JTextArea. As well, I would like to have the text areas as resizeable.
Something like this:
comes to mind, but as a JTextArea instead of just a square.
Is there something in Java that would allow me to easily do this? I first thought to allow the user to draw a rectangle and just grab the co-ordinates and size to create the JTextArea. I am unsure on how to do the resizing though.
Edit: "Component Resizer / Reszing" was the term I was looking for and I'm adding it here in case someone else is looking for something similar!

You can found a solution here
I have already try it and the result is very well. In the tutorial there is a reference to another implementation here.

The resizing the JTextArea can be done easily enough via calling setBounds(...) on it -- or better on the JScrollPane that holds it, but you will need to use a null or similar (JLayeredPane) layout on the container that holds the JTextArea and will likely need to repaint the container after resizing the JScrollPane. You will also have to revalidate the scrollpane's viewport so it will re-layout the textarea that it holds.
e.g.,
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
#SuppressWarnings("serial")
public class ResizeableTextArea extends JPanel {
private static final int PREF_WIDTH = 700;
private static final int PREF_HEIGHT = 500;
private static final int ROWS = 60;
private static final int COLS = 80;
private static final Color RECT_COLOR = new Color(180, 180, 255);
private JTextArea textArea = new JTextArea(ROWS, COLS);
private JScrollPane scrollPane = new JScrollPane(textArea);
private int x, y, width, height;
private boolean drawRect = false;
public ResizeableTextArea() {
setLayout(null);
add(scrollPane);
MyMouseAdapter myMouseAdapter = new MyMouseAdapter();
addMouseListener(myMouseAdapter);
addMouseMotionListener(myMouseAdapter);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (drawRect) {
g.setColor(RECT_COLOR);
g.drawRect(x, y, width, height);
}
}
#Override
public Dimension getPreferredSize() {
return new Dimension(PREF_WIDTH, PREF_HEIGHT);
}
private class MyMouseAdapter extends MouseAdapter {
private int innerX, innerY;
#Override
public void mousePressed(MouseEvent e) {
x = e.getX();
y = e.getY();
innerX = x;
innerY = y;
width = 0;
height = 0;
drawRect = true;
}
#Override
public void mouseDragged(MouseEvent e) {
calcBounds(e);
drawRect = true;
ResizeableTextArea.this.repaint();
}
#Override
public void mouseReleased(MouseEvent e) {
calcBounds(e);
drawRect = false;
scrollPane.setBounds(x, y, width, height);
scrollPane.getViewport().revalidate();
ResizeableTextArea.this.repaint();
}
private void calcBounds(MouseEvent e) {
width = Math.abs(innerX - e.getX());
height = Math.abs(innerY - e.getY());
x = Math.min(innerX, e.getX());
y = Math.min(innerY, e.getY());
}
}
private static void createAndShowUI() {
JFrame frame = new JFrame("ResizeableTextArea");
frame.getContentPane().add(new ResizeableTextArea());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
createAndShowUI();
}
});
}
}

You should be able to use the Component Resizer.

that not really good idea, sure is possible to put Image or ImageIcon as BackGround, better would be use for that JLabel with Icon, then you can painting selection easily

JScrollpane resizing with variable-sized content

My resizable JScrollPane's content has a minimum width. If the JScrollPane is smaller than this width, horizontal scroll bars should appear. If it's greater than this width, the viewport content should expand to fill up the entire viewport.
Seems like a simple concept, and I've got something that's working, but it feels like a hack:
import javax.swing.*;
import java.awt.*;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;
public class SSBTest {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
final Component view = new MyView();
final JScrollPane jScrollPane = new JScrollPane(view);
jScrollPane.addComponentListener(new ComponentAdapter() {
#Override
public void componentResized(final ComponentEvent e) {
final Dimension minimumSize = view.getMinimumSize();
final int width = Math.max(minimumSize.width, jScrollPane.getViewport().getWidth());
view.setPreferredSize(new Dimension(width, minimumSize.height));
}
});
showInDialog(jScrollPane);
}
});
}
private static void showInDialog(final JScrollPane jScrollPane) {
final JDialog dialog = new JOptionPane(jScrollPane).createDialog("JScrollPane Resize Test");
dialog.setResizable(true);
dialog.setModal(true);
dialog.setVisible(true);
System.exit(0);
}
private static final class MyView extends JPanel {
#Override
protected void paintComponent(final Graphics g) {
super.paintComponent(g);
g.setColor(Color.RED);
g.drawString("Dimensions are " + getSize(), 10, 20);
g.drawRect(0, 0, getMinimumSize().width-1, getMinimumSize().height-1);
g.setColor(Color.BLUE);
g.drawRect(0, 0, getPreferredSize().width-1, getPreferredSize().height-1);
}
#Override
public Dimension getMinimumSize() {
return new Dimension(200, 200);
}
#Override
public Dimension getPreferredSize() {
return super.getPreferredSize();
}
}
}
Resizing the dialog triggers the ComponentListener, which explicitly sets the preferred size of the viewport view, triggering component validation. However, resizing causes jittery scroll bars. Is there a cleaner way to do this?
EDIT: thanks to camickr for the ScrollablePanel link, I've modified my JPanel class to implement Scrollable, and dynamically change the return value for getScrollableTracksViewportWidth().
When the viewport is big, I return true for getScrollableTracksViewportWidth(), telling the JScrollPane to fill the view with my component. When the viewport is small, I return false, so the scrollbars appear.
import javax.swing.*;
import java.awt.*;
public class SSBTest {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
final Component view = new MyView();
final JScrollPane jScrollPane = new JScrollPane(view);
showInDialog(jScrollPane);
}
});
}
private static void showInDialog(final JScrollPane jScrollPane) {
final JDialog dialog = new JOptionPane(jScrollPane).createDialog("JScrollPane Resize Test");
dialog.setResizable(true);
dialog.setModal(true);
dialog.setVisible(true);
System.exit(0);
}
private static final class MyView extends JPanel implements Scrollable {
#Override
protected void paintComponent(final Graphics g) {
super.paintComponent(g);
g.setColor(Color.RED);
g.drawString("MyView: " + getWidth() + "x" + getHeight(), 10, 20);
g.drawRect(0, 0, getMinimumSize().width-1, getMinimumSize().height-1);
g.setColor(Color.BLUE);
g.drawRect(0, 0, getPreferredSize().width-1, getPreferredSize().height-1);
g.drawString("Preferred/Minimum Size", 10, getPreferredSize().height/2);
g.setColor(Color.GREEN);
g.drawLine(0, 0, getWidth(), getHeight());
}
#Override
public Dimension getMinimumSize() {
return new Dimension(200, 200);
}
#Override
public Dimension getPreferredSize() {
return getMinimumSize();
}
public Dimension getPreferredScrollableViewportSize() {
return getPreferredSize();
}
public int getScrollableUnitIncrement(final Rectangle visibleRect, final int orientation, final int direction) {
return 10;
}
public int getScrollableBlockIncrement(final Rectangle visibleRect, final int orientation, final int direction) {
return visibleRect.width;
}
public boolean getScrollableTracksViewportWidth() {
final Container viewport = getParent();
return viewport.getWidth() > getMinimumSize().width;
}
public boolean getScrollableTracksViewportHeight() {
return true;
}
}
}

Not sure, but you might be able to use the Scrollable Panel. You can configure the component resizing (try using STRETCH). The code works on the preferred size of the component not the minimum size so it may not be exactly what you want.

Painted content invisible while resizing in Java

Please note I haven't tested this on a Windows-machine only on a Mac-machine. I'm not so sure whether this also occurs on a Windows-machine...
When I resize my Java-application the content is invisible. I already found a way to fix it after resizing it, but not while the user is resizing the window.
I'm not using Swing or something because it makes my binary so slow (in my opinion).
The structure is like this:
Frame My main-window
Container Content view of main-window
Container-based subviews that including the paint(Graphics g)-method
I've added all listeners to My main-window and now I'm able to redraw the Content-view after resizing the window.
public void componentResized(ComponentEvent e) {
this.contentView.paint(this.contentView.getGraphics());
}
I am beware of the fact using the paint(getGraphics())-method isn't a really good way to do this, but since the repaint()-method doesn't do anything at all, it's the only working possibility.
While resizing, all painted content becomes invisible. However, when I add a Button-instance to my Content-view and resize my Main-window, the button doesn't get invisible.
I am able to trace the 'live'-resize event:
public void componentMoved(ComponentEvent e) {
System.out.println("Live-resize");
}
When I start resizing this method is not being called.
While resizing it generates "Live-resize" in my log every single pixel I resize the window.
When I stop resizing this method is not being called, the componentResized-method does.
When I add my repaint-method (or the official repaint-method) to the 'live'-resize event like this, I still get the output, however, it's not repainting or something
public void componentMoved(ComponentEvent e) {
System.out.println("Live-resize");
this.contentView.paint(this.contentView.getGraphics());
}
Or
public void componentMoved(ComponentEvent e) {
System.out.println("Live-resize");
this.contentView.repaint();
}
When I minimize my application to the dock and maximize the application again, the same thing happens, I guess that the same code is needed to fix this.
I'm not using Graphics2D or something, just Graphics.
Could you please explain me how I can repaint the views?
Thanks in advance,
Tim

For reference, here is the same program using Swing. Because JPanel is double buffered, it doesn't flicker as the mouse is released after resizing.
import java.awt.*;
import java.awt.event.*;
import java.util.Random;
import javax.swing.*;
public class SwingPaint {
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.add(new CirclePanel());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
private static class CirclePanel extends JPanel {
private static final Random r = new Random();
public CirclePanel() {
this.setPreferredSize(new Dimension(320, 240));
this.setForeground(new Color(r.nextInt()));
this.addMouseListener(new MouseAdapter() {
#Override
public void mousePressed(MouseEvent e) {
CirclePanel.this.update();
}
});
}
public void update() {
this.setForeground(new Color(r.nextInt()));
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Dimension size = this.getSize();
int d = Math.min(size.width, size.height) - 10;
int x = (size.width - d) / 2;
int y = (size.height - d) / 2;
g.fillOval(x, y, d, d);
g.setColor(Color.blue);
g.drawOval(x, y, d, d);
}
}
}

I'm more familiar with Swing, but the article Painting in AWT and Swing distinguishes between system- and application-triggered painting. The example below shows how the system invokes paint() as the window is resized, while the application invokes repaint(), which calls update(), in response to a mouse event. The behavior is cross-platform.
import java.awt.*;
import java.awt.event.*;
import java.util.Random;
public class AWTPaint {
public static void main(String[] args) {
Frame frame = new Frame();
frame.add(new CirclePanel());
frame.addWindowListener(new WindowAdapter() {
#Override
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
frame.pack();
frame.setVisible(true);
}
private static class CirclePanel extends Panel {
private static final Random r = new Random();
public CirclePanel() {
this.setPreferredSize(new Dimension(320, 240));
this.setForeground(new Color(r.nextInt()));
this.addMouseListener(new MouseAdapter() {
#Override
public void mousePressed(MouseEvent e) {
CirclePanel.this.repaint();
}
});
}
#Override
public void update(Graphics g) {
this.setForeground(new Color(r.nextInt()));
}
#Override
public void paint(Graphics g) {
Dimension size = this.getSize();
int d = Math.min(size.width, size.height) - 10;
int x = (size.width - d) / 2;
int y = (size.height - d) / 2;
g.fillOval(x, y, d, d);
g.setColor(Color.blue);
g.drawOval(x, y, d, d);
}
}
}

Okay, I finally fixed it.
Instead of redrawing it every time in the paint(Graphics g)-method, you need to buffer the output and only redraw that image (I kinda hoped Java would be already doing that, just like Obj-C).
public BufferedImage buffer;
public void redraw() {
buffer = new BufferedImage(
200, // height
300, // width
BufferedImage.TYPE_4BYTE_ABGR); // ABGR = RGBA, 4-byte (r, g, b, a) per pixel
Graphics g = buffer.getGraphics();
// do your drawing here
if (this.getGraphics()) {
// 'this' is already shown, so it needs a redraw
this.paint(this.getGraphics()); // little hack
}
}
public void update(Graphics g) {
this.paint(g);
}
public void paint(Graphics g) {
g.drawImage(buffer, 0, 0, this);
}
Now, when you minimize the window and maximize it again, the paintings remain. Only, the window's flickering now for .1-second or so, but I don't really care about that.