Is there a way such that a component that is added to the BorderLayout.PAGE_START area will become scrollable if (and only if) there's not enough space?
I have attached a minimal example. If you resize the complete frame the label in the center will become scrollable, the label at the top won't.
Unfortunately, I can't change the BorderLayout.PAGE_START positioning, as this is given by a framework. However I do have full control over the creation of myComponent.
public static void main(String[] args){
JPanel panel = new JPanel(new BorderLayout());
JComponent myComponent = new JScrollPane(new JLabel("<html>START-START<br><br>START-START</html>"));
panel.add(myComponent, BorderLayout.PAGE_START);
panel.add(new JScrollPane(new JLabel("<html>CENTER-CENTER<br><br>CENTER-CENTER</html>")), BorderLayout.CENTER);
final JFrame mainframe = new JFrame("Test");
mainframe.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
mainframe.getContentPane().add(panel);
javax.swing.SwingUtilities.invokeLater(() -> {
mainframe.pack();
mainframe.setVisible(true);});
}
Is there a way such that a component that is added to the BorderLayout.PAGE_START area will become scrollable if there's not enough space?
Yes there is. Make its preferred height less than its actual height. BorderLayout respects the preferred height of the component contained at PAGE_START, so it doesn't matter how many lines you put in your JLabel, it will be displayed at its preferred height – without scrollbars.
Try the following.
public static void main(String[] args) {
JPanel panel = new JPanel(new BorderLayout());
JComponent myComponent = new JScrollPane(new JLabel("<html>START-START<br><br>START-START</html>"));
myComponent.setPreferredSize(new Dimension(100, 20));
panel.add(myComponent, BorderLayout.PAGE_START);
panel.add(new JScrollPane(new JLabel("<html>CENTER-CENTER<br><br>CENTER-CENTER</html>")),
BorderLayout.CENTER);
final JFrame mainframe = new JFrame("Test");
mainframe.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
mainframe.getContentPane().add(panel);
javax.swing.SwingUtilities.invokeLater(() -> {
mainframe.pack();
mainframe.setVisible(true);
});
}
EDIT
The below code doesn't give the best result but I think it is the way to go. You just need to play around with the different sizes of the different components.
I added a ComponentListener to the content pane of the JFrame. When the JFrame is resized, you need to recalculate the heights of the top component and the center component according to your needs and then update the relevant component sizes. Note that the below code is not a complete solution but hopefully enough to allow you to arrive at a complete solution.
public static void main(String[] args) {
final JFrame mainframe = new JFrame("Test");
JLabel topLabel = new JLabel("<html>START-START<br><br>START-START");
JScrollPane topPane = new JScrollPane(topLabel);
mainframe.add(topPane, BorderLayout.PAGE_START);
JLabel centerLabel = new JLabel("<html>CENTER-CENTER<br><br>CENTER-CENTER");
centerLabel.setMinimumSize(centerLabel.getPreferredSize());
JPanel centerPane = new JPanel();
centerPane.add(centerLabel);
mainframe.add(centerPane, BorderLayout.CENTER);
javax.swing.SwingUtilities.invokeLater(() -> {
mainframe.pack();
mainframe.setVisible(true);
final Dimension centerPaneDim = centerPane.getPreferredSize();
final Dimension topLabelDim = topLabel.getPreferredSize();
mainframe.getContentPane().addComponentListener(new ComponentListener() {
#Override
public void componentShown(ComponentEvent e) {
// Do nothing.
}
#Override
public void componentResized(ComponentEvent e) {
Dimension size = e.getComponent().getSize();
if (size.height < centerPaneDim.height + topLabelDim.height + 10) {
topPane.setPreferredSize(new Dimension(topLabelDim.width, 10 + size.height - centerPaneDim.height));
}
else {
topPane.setPreferredSize(new Dimension(topLabelDim.width, topLabelDim.height + 10));
}
e.getComponent().revalidate();
e.getComponent().repaint();
}
#Override
public void componentMoved(ComponentEvent e) {
// Do nothing.
}
#Override
public void componentHidden(ComponentEvent e) {
// Do nothing.
}
});
});
}
Related
I can't seem to figure out how I would add in a background WITH all of my panels showing.
I tried to set the JFrame content pane as a label with an imageicon and the frame does show, it just doesn't show the image like above.
This is the code that I've used.
frame.setContentPane(new JLabel(new ImageIcon("res/Wallpaper.png")));
The second attempt I've used is to ADD (not set) an image into the content pane of the frame. This did not work as shown in the second picture above and it only shows the panels but no background. The code is on the bottom.
frame.getContentPane().add(new JLabel(new ImageIcon("res/Wallpaper.png")));
The third attempt I've tried is to create a subclass of JComponent and Override the paintComponents method then setan object of it as the contentpane. This does not work and instead turns my screen blank.
Here is the code I've used and the class code is in the 1st answer of this link Setting background images in JFrame. The result is the 3rd image of this post.
File img = new File("res/Wallpaper.png");
BufferedImage myImage;
try {
myImage = ImageIO.read(img);
frame.setContentPane(new ImagePanel(myImage));
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
The 4th attempt I've tried is adding the picture into the main panel that fills up the screen. This does not work at all and instead breaks the image in half so half of the screen has the image half doesn't.
Here is the code I've used for my 4th attempt. The result is the 4th last image on the top.
BufferedImage myPicture;
try {
myPicture = ImageIO.read(new File("res/Wallpaper.png"));
JLabel picLabel = new JLabel(new ImageIcon(myPicture));
pMain.add(picLabel);
} catch (IOException e) {
e.printStackTrace();
}
I'm not sure why the JPanels aren't showing up.
I know that in the 1st example when you set the frame as a JLabel it gives it a null layout but that was the only way I could find to DISPLAY the image.
I would like to somehow add the panels ontop of the frame with that background but after reading numerous threads I could not find out how.
If anyone does find out, please post the code and explain if you can. I also have the class get the system class theme that sets it into the theme of what the computer is using. Ex. I am using a windows operating system so it shows it kind of like my operating system.
This thread is not a duplicate. In other threads they only have a frame but in my thread I have several panels that aren't showing for some particular reason.
EDIT: I don't know what's up, I tried to use this thread Setting background images in JFrame but I had no luck.
The 1st method it gave me I tried and then instead of showing anything it showed nothing at all, no picture no components nothing at all. In case if you need more information I have: 4 JPanels on the bottom of the screen, I also have a border surrounding my window but doesn't show up in the 1st window. I also have borders surrounding my panels too.
So the 1st method I've tried setting it on the content pane, image loads but all of the components are gone.
2nd method I've tried adding it into the content pane but yet again with no luck and I get a panel with no background.
3rd method I've tried is creating a separate class and overriding the paintComponent method and adding an image to the constructor of it then placing this object of the class into the setcontentPane() parameter of the frame. Does not work at all, all I get is a blank frame.
Code I am using for my frame:
public class LoginScreen {
JCheckBox remember_User;
JButton login, create_Account, forums, faqs;
Border whiteLine;
JTextField userField;
JFormattedTextField passField;
private void createView() {
// Created essential details for the frame
JFrame frame = new JFrame();
frame.setTitle("Name of the game");
frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Defining panels and a constraint on the bottomPanel.
// More info - Total amt of panels: 5
// pLogin and pInfo are in the bottomCompPanel and bottomCompPanel is in
// bottomPanel
// bottom panel is in pMain
// Giving panels some attributes like backgrounds and borders
JPanel pMain = new JPanel(new BorderLayout());
pMain.setBorder(BorderFactory.createMatteBorder(3, 3, 6, 3,
Color.DARK_GRAY));
frame.getContentPane().add(pMain);
whiteLine = BorderFactory.createLineBorder(Color.LIGHT_GRAY);
JPanel pLogin = new JPanel(new GridBagLayout());
pLogin.setBackground(Color.cyan);
pLogin.setPreferredSize(new Dimension(400, 250));
pLogin.setBorder(whiteLine);
JPanel pInfo = new JPanel(new GridBagLayout());
pInfo.setBackground(Color.green);
pInfo.setPreferredSize(new Dimension(200, 100));
pInfo.setBorder(whiteLine);
JPanel bottomCompPanel = new JPanel(new GridBagLayout());
GridBagConstraints bGBC = new GridBagConstraints();
bGBC.gridx = 0;
bGBC.gridy = 0;
bGBC.insets = new Insets(0, 20, 0, 0);
bGBC.anchor = GridBagConstraints.PAGE_END;
bottomCompPanel.add(pLogin, bGBC);
bGBC.gridx++;
bottomCompPanel.add(pInfo, bGBC);
JPanel bottomPanel = new JPanel(new FlowLayout(FlowLayout.RIGHT));
bottomPanel.add(bottomCompPanel);
pMain.add(bottomPanel, BorderLayout.SOUTH);
frame.setVisible(true);
}
public static void main(String[] args) {
LoginScreen login = new LoginScreen();
login.createView();
}
}
POST UPDATE 2: Here is the code that I've used using #peeskillet's 1st method. It works sort of but it gives me the same results as the 3rd photo, a cut off picture. P.S I add the panels down at the bottom to my JLabel at the end.
private void createView() {
//Created essential details for the frame
JFrame frame = new JFrame();
frame.setTitle("Name of the game");
frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
JLabel background = new JLabel(new ImageIcon("res/Wallpaper.png"));
background.setLayout(new BorderLayout());
frame.setContentPane(background);
//Defining panels and a constraint on the bottomPanel.
//More info - Total amt of panels: 5
//pLogin and pInfo are in the bottomCompPanel and bottomCompPanel is in bottomPanel
//bottom panel is in pMain
//Giving panels some attributes like backgrounds and borders
whiteLine = BorderFactory.createLineBorder(Color.LIGHT_GRAY);
JPanel pLogin = new JPanel(new GridBagLayout());
pLogin.setBackground(Color.cyan);
pLogin.setPreferredSize(new Dimension(400,250));
pLogin.setBorder(whiteLine);
JPanel pInfo = new JPanel(new GridBagLayout());
pInfo.setBackground(Color.green);
pInfo.setPreferredSize(new Dimension(200,100));
pInfo.setBorder(whiteLine);
JPanel bottomCompPanel = new JPanel(new GridBagLayout());
GridBagConstraints bGBC = new GridBagConstraints();
bGBC.gridx = 0;
bGBC.gridy = 0;
bGBC.insets = new Insets(0,20,0,0);
bGBC.anchor = GridBagConstraints.PAGE_END;
bottomCompPanel.add(pLogin, bGBC);
bGBC.gridx++;
bottomCompPanel.add(pInfo, bGBC);
JPanel bottomPanel = new JPanel(new FlowLayout(FlowLayout.RIGHT));
bottomPanel.add(bottomCompPanel);
background.add(bottomPanel, BorderLayout.SOUTH);
"I tried to set the JFrame content pane as a label with an imageicon"
You need to set the layout on the JLabel. It will be null be default.
import java.awt.*;
import java.net.URL;
import javax.swing.*;
import javax.swing.border.Border;
public class BackgroundImage {
private static final String IMG = "http://i.stack.imgur.com/JEoYs.jpg";
private void init() throws Exception {
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JLabel background = new JLabel(new ImageIcon(new URL(IMG)));
background.setLayout(new GridBagLayout());
background.add(loginPanel());
f.setContentPane(background);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
private JPanel loginPanel() {
Border whiteLine = BorderFactory.createLineBorder(Color.LIGHT_GRAY);
JPanel pLogin = new JPanel(new GridBagLayout());
pLogin.setBackground(Color.cyan);
pLogin.setPreferredSize(new Dimension(400, 250));
pLogin.setBorder(whiteLine);
return pLogin;
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
try {
new BackgroundImage().init();
} catch (Exception ex) {}
});
}
}
"I've tried is to create a subclass of JComponent and Override the paintComponents method then setan object of it as the contentpane"
Should be paintComponent (no "s"), but just like with JLabel, you need to set the layout. JComponent layout is null be default. You also need to give it a preferred size when painting.
import java.awt.*;
import java.net.URL;
import javax.swing.*;
import javax.swing.border.Border;
public class BackgroundImage {
private static final String IMG = "http://i.stack.imgur.com/JEoYs.jpg";
private void init() throws Exception {
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JComponent background = new BackgroundComponent(new ImageIcon(new URL(IMG)));
background.setLayout(new GridBagLayout());
background.add(loginPanel());
f.setContentPane(background);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
private JPanel loginPanel() {
Border whiteLine = BorderFactory.createLineBorder(Color.LIGHT_GRAY);
JPanel pLogin = new JPanel(new GridBagLayout());
pLogin.setBackground(Color.cyan);
pLogin.setPreferredSize(new Dimension(400, 250));
pLogin.setBorder(whiteLine);
return pLogin;
}
class BackgroundComponent extends JComponent {
public ImageIcon background;
public BackgroundComponent(ImageIcon background) {
this.background = background;
}
#Override
public Dimension getPreferredSize() {
return new Dimension(background.getIconWidth(), background.getIconHeight());
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(background.getImage(),
0, 0,
background.getIconWidth(),
background.getIconHeight(), this);
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
try {
new BackgroundImage().init();
} catch (Exception ex) {}
});
}
}
Using (extending) JPanel instead of JComponent would be similar except JPanel does have a default layout which is FlowLayout.
UPDATE
To get your desired layout, you need to play around with the different layout managers. The combination I used is
Outer (main panel) -- BorderLayout
Bottom (bottom panel) -- BoxLayout inside (south) of outer layout
For the BorderLayout, you need to make sure the panel opaque property is set to false, as BorderLayout will stretch the panel and cover the background.
For the BoxLayout, you need to make sure to set the maximum size and the preferred size
import java.awt.*;
import java.net.URL;
import javax.swing.*;
import javax.swing.border.Border;
public class BackgroundImage {
private static final String IMG = "http://i.stack.imgur.com/JEoYs.jpg";
private final Border whiteLine = BorderFactory.createLineBorder(Color.LIGHT_GRAY);
private void init() throws Exception {
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JComponent background = new BackgroundComponent(new ImageIcon(new URL(IMG)));
background.setLayout(new BorderLayout());
background.add(bottomPanel(), BorderLayout.SOUTH);
f.setContentPane(background);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
private JPanel bottomPanel() {
JPanel bottomPanel = new JPanel();
bottomPanel.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
BoxLayout layout = new BoxLayout(bottomPanel, BoxLayout.X_AXIS);
bottomPanel.setLayout(layout);
bottomPanel.setOpaque(false);
bottomPanel.add(Box.createHorizontalGlue());
bottomPanel.add(loginPanel());
bottomPanel.add(Box.createRigidArea(new Dimension(10, 0)));
bottomPanel.add(infoPanel());
return bottomPanel;
}
private JPanel infoPanel() {
JPanel pInfo = new JPanel(new GridBagLayout());
pInfo.setAlignmentY(Component.BOTTOM_ALIGNMENT);
pInfo.setBackground(Color.green);
pInfo.setMaximumSize(new Dimension(200, 100));
pInfo.setPreferredSize(new Dimension(200, 100));
pInfo.setBorder(whiteLine);
return pInfo;
}
private JPanel loginPanel() {
JPanel pLogin = new JPanel(new GridBagLayout());
pLogin.setAlignmentY(Component.BOTTOM_ALIGNMENT);
pLogin.setBackground(Color.cyan);
pLogin.setPreferredSize(new Dimension(400, 250));
pLogin.setMaximumSize(new Dimension(400, 250));
pLogin.setBorder(whiteLine);
return pLogin;
}
class BackgroundComponent extends JComponent {
public ImageIcon background;
public BackgroundComponent(ImageIcon background) {
this.background = background;
}
#Override
public Dimension getPreferredSize() {
return new Dimension(background.getIconWidth(), background.getIconHeight());
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(background.getImage(),
0, 0,
background.getIconWidth(),
background.getIconHeight(), this);
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
try {
new BackgroundImage().init();
} catch (Exception ex) {
}
});
}
}
For more information about using the different layout managers, see
Laying Out Components Within a Container
You can try JLayeredPane and setOpaque(boolean) method.
Code:
public class BackgroundImageTest{
private JFrame frame;
public BackgroundImageTest() {
frame = new JFrame("Background Image Frame");
// set frame properties
JPanel panel = new JPanel(new FlowLayout());
panel.setOpaque(false);
JButton btn = new JButton("Change Background");
panel.add(btn);
btn.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent ae) {
setBackgroundImage(getImage(new File("Wallpaper2.png")));
}
});
JPanel main = (JPanel) frame.getContentPane();
main.setLayout(new FlowLayout());
main.add(panel);
main.setOpaque(false);
setBackgroundImage(getImage(new File("Wallpaper.png")));
frame.setVisible(true);
}
private Image getImage(File imageFile) {
BufferedImage image = null;
try {
image = ImageIO.read(imageFile);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return image;
}
private void setBackgroundImage(Image img) {
if(img == null) return;
ImageIcon ii = new ImageIcon(img);
JLabel lblBG = new JLabel(ii);
lblBG.setName("BackgroundImageLabel");
JLayeredPane layeredPane = frame.getLayeredPane();
Component[] comps = layeredPane.getComponentsInLayer(new Integer(Integer.MIN_VALUE));
for (int i = 0; i < comps.length; i++) {
System.out.println(comps[i].getName());
if (comps[i] instanceof JLabel && comps[i].getName().equals("BackgroundImageLabel")){
layeredPane.remove(comps[i]);
break;
}
}
layeredPane.add(lblBG, new Integer(Integer.MIN_VALUE));
lblBG.setBounds(0,0,ii.getIconWidth(), ii.getIconHeight());
}
}
I have a custom component called FixtureComponent that extends JPanel, it is basically a JPanel containing a number of controls placed inside it, each with it's own size and location. What I am trying to do is to place a number of FixtureComponent vertically in my JFrame as follows:
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
main frame = new main();
FixtureComponent comPanel = new FixtureComponent();
frame.getContentPane().setLayout(new BoxLayout(frame.getContentPane(), BoxLayout.Y_AXIS));
frame.setSize(300, 400);
frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
for (Integer i = 0; i < 20; i++)
{
frame.getContentPane().add(comPanel);
}
frame.setVisible(true);
}
});
}
The problem I am getting is when I run the above code, I get a single FixtureComponent placed at the top of the JFrame instead of getting 20 FixtureComponents placed vertically above each other.
And I would like to also know in case of that I successfully got the above code to work, how to add a scroll bar to scroll across the FixtureComponent?
Thank you.
Create and add a JScrollPane to the frame, setting the JScrollPane context to the content you need scrolling, in the example below this is a JPanel named container.
Add your FixtureComponent objects to container, and boom. Here's the code:
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
Main frame = new Main();
JPanel container = new JPanel();
container.setLayout(new BoxLayout(container, BoxLayout.Y_AXIS));
JScrollPane scroller = new JScrollPane(container);
scroller.setPreferredSize(new Dimension(200, 1000));
for (Integer i = 0; i < 20; i++) {
FixtureComponent fixture = new FixtureComponent();
container.add(fixture);
}
frame.setLayout(new BorderLayout());
frame.add(scroller, BorderLayout.WEST);
frame.setSize(300, 400);
frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
frame.setVisible(true);
}
});
}
I have a panel with layout (for example, BorderLayout) and a JScrollPane on its center. JScrollPane has content inside it (a JPanel)
The thing is, that when this JScrollPane resizes, I do not want its content to resize. For example, if layout increases the JScrollPane, I want its content to be as small it was (and occupy only part of the pane), but it resizes to fit pane.
I also need an opportunity to reduce content inside the pane and increase it manually (there is no problems with increasing, they are in reducing).
So, how can I achieve content size independency? Of course, I need to save scrolling features, if content will be bigger than JScrollPane.
Here is a simple example:
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class TestScroll extends JFrame {
public TestScroll() {
setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
setSize(500, 500);
init();
}
private void init() {
setLayout(new BorderLayout());
// Inner panel
final JPanel innerPanel = new JPanel();
innerPanel.setOpaque(true);
innerPanel.setBackground(Color.BLUE);
innerPanel.setPreferredSize(new Dimension(200, 200));
// Scroll
final JScrollPane scrollPane = new JScrollPane(innerPanel);
add(scrollPane, BorderLayout.CENTER);
// Buttons
JPanel buttonPanel = new JPanel();
JButton extendButton = new JButton("Extend inner panel");
extendButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
innerPanel.setPreferredSize(new Dimension(innerPanel.getWidth() * 2,
innerPanel.getHeight() * 2));
innerPanel.revalidate();
}
});
buttonPanel.add(extendButton);
JButton reduceButton = new JButton("Reduce inner panel");
reduceButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
innerPanel.setPreferredSize(new Dimension(innerPanel.getWidth() / 2,
innerPanel.getHeight() / 2));
innerPanel.revalidate();
}
});
buttonPanel.add(reduceButton);
add(buttonPanel, BorderLayout.NORTH);
setVisible(true);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
new TestScroll();
}
});
}
}
So, problem statement:
I do not want inner panel to stretch to the pane (but pane can be resized by outer layout, so the panel must just keep its size).
I want to be able to reduce inner panel manually so it can occupy only a part of the scroll pane.
And, of course, I want to save scrolling functionality when inner panel is larger than scroll pane.
Did you follow Andrew's link about using layout managers to achieve your goal?
Here is another simple example:
//final JScrollPane scrollPane = new JScrollPane(innerPanel);
JPanel outer = new JPanel();
outer.add( innerPanel );
final JScrollPane scrollPane = new JScrollPane(outer);
My question shows I'm new in JAVA ;)
I'm trying to add a JPanel to JScrollPane but When I add a component bigger than JPanel the JScrollPane does not work.
I can fix it by setting JScrollPane smaller than JPanel but this is not a right solution ( I want to add components to JPannel dynamically later).
scroll2.setPreferredSize(new Dimension(500, 500));
What is solution? Thank you
public class Main extends JFrame {
private JPanel finalPan2;
JScrollPane scroll2;
public Main() throws HeadlessException {
super("V4.0.3");
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception e) {
e.printStackTrace();
}
setSize(520, 540);
setLocation(0, 200);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setLayout(new FlowLayout());
setResizable(false);
setVisible(true);
finalPan2 = new JPanel(new FlowLayout(FlowLayout.CENTER));
finalPan2.setPreferredSize(new Dimension(620, 540));
JButton bb = new JButton("Big Button");
bb.setPreferredSize(new Dimension(50, 800));
finalPan2.add(bb);
scroll2 = new JScrollPane(finalPan2);
scroll2.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
scroll2.setPreferredSize(new Dimension(500, 500));
add(scroll2, BorderLayout.CENTER);
setLocationRelativeTo(null);
}
public static void main(String args[]) {
EventQueue.invokeLater(new Runnable() {
// #Override
public void run() {
Main ba = new Main();
}
});
}
}
You have the ScrollPane for the JPanel, but the JPanel doesn't change size to accomodate for the size of the JButton because you have set its preferred size. If you take out finalPan2.setPreferredSize(new Dimension(620, 540));, the panel should resize to fit the button, and the scrollpane should work.
I have a class that extends a JPanel called Row. I have a bunch of Row added to a JLabel, the code is the following:
JFrame f=new JFrame();
JPanel rowPanel = new JPanel();
//southReviewPanel.setPreferredSize(new Dimension(400,130));
rowPanel.setLayout(new BoxLayout(rowPanel, BoxLayout.Y_AXIS));
rowPanel.add(test1);
rowPanel.add(test1);
rowPanel.add(test2);
rowPanel.add(test3);
rowPanel.add(test4);
rowPanel.setPreferredSize(new Dimension(600, 400));
rowPanel.setMaximumSize(rowPanel.getPreferredSize());
rowPanel.setMinimumSize(rowPanel.getPreferredSize());
f.setSize(new Dimension(300,600));
JScrollPane sp = new JScrollPane(rowPanel);
sp.setSize(new Dimension(300,600));
f.add(sp);
f.setVisible(true);
where test1...etc is a Row. However when I resize the window the layout of the Row somehow becomes messy (it resizes as well)... how can I prevent this from happening?
Read the Swing tutorial on Using Layout Managers. Each layout manager has its own rules about what happens when the container is resized. Experiment and play.
In the case of a BoxLayout it should respect the maximum size of the components added to the panel so you can do:
childPanel.setMaximumSize( childPanel.getPreferredSize() );
If you need more help post your SSCCE demonstrating the problem.
I took the code in http://download.oracle.com/javase/tutorial/uiswing/examples/layout/BoxLayoutDemoProject/src/layout/BoxLayoutDemo.java and adapted it with what you are trying to do, only using buttons instead of custom JPanels:
public class BoxLayoutDemo {
public static void addComponentsToPane(Container pane) {
JPanel rowPanel = new JPanel();
pane.add(rowPanel);
rowPanel.setLayout(new BoxLayout(rowPanel, BoxLayout.Y_AXIS));
rowPanel.add(addAButton("Button 1"));
rowPanel.add(addAButton("Button 2"));
rowPanel.add(addAButton("Button 3"));
rowPanel.add(addAButton("Button 4"));
rowPanel.add(addAButton("5"));
rowPanel.setPreferredSize(new Dimension(600, 400));
rowPanel.setMaximumSize(rowPanel.getPreferredSize());
rowPanel.setMinimumSize(rowPanel.getPreferredSize());
}
private static JButton addAButton(String text) {
JButton button = new JButton(text);
button.setAlignmentX(Component.CENTER_ALIGNMENT);
return button;
}
private static void createAndShowGUI() {
JFrame frame = new JFrame("BoxLayoutDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Set up the content pane.
addComponentsToPane(frame.getContentPane());
//Display the window.
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}
The end result is this:
As you can see, the button row is perfectly aligned. If you resize the JFrame, they stay aligned. Is that what you are looking for?