I have a small problem when using JScrollPane in my Java application.
I have a JScrollPane containing a JPanel.
This JPanel is dynamically updated with buttons (vertically ordered) that can be of any width.
The JPanel automatically adjusts its width to the largest JButton component inside.
Now when the vertical scrollbar appears, it takes away some space on the right side of my JPanel, which causes the largest buttons not to appear completely. I don't want to use a horizontal scrollbar in addition to display the whole button.
Is there a way to resize my JPanel when a scrollbar appears, so it appears nicely next to my buttons? Or is there any other way to have the scrollbar appear next to my JPanel?
Thanks in advance!
EDIT: Here is a demo of my problem. When you resize the window to a smaller height, a little part of the buttons on the right side gets covered.
import java.awt.BorderLayout;
import java.awt.EventQueue;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import java.awt.GridLayout;
/**
* #author Dylan Kiss
*/
public class Demo {
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
JFrame myFrame = new JFrame("Demo");
JPanel sideBar = new JPanel();
JPanel centerPanel = new JPanel();
centerPanel.add(new JLabel("This is the center panel."));
JPanel buttonContainer = new JPanel();
JButton myButton = null;
for (int i = 0; i < 20; i++) {
buttonContainer.setLayout(new GridLayout(20, 1, 0, 0));
myButton = new JButton("This is my button nr. " + i);
buttonContainer.add(myButton);
}
sideBar.setLayout(new BorderLayout(0, 0));
JScrollPane scrollPane = new JScrollPane(buttonContainer);
sideBar.add(scrollPane);
myFrame.getContentPane().add(sideBar, BorderLayout.WEST);
myFrame.getContentPane().add(centerPanel, BorderLayout.CENTER);
myFrame.setLocationByPlatform(true);
myFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
myFrame.pack();
myFrame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
}
Here is a simple, not pretty, solution:
scrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
EDIT:
I thought that might not do the job in your case. Here is a better solution although it has quite a lot of boilerplate:
private class ButtonContainerHost extends JPanel implements Scrollable {
private static final long serialVersionUID = 1L;
private final JPanel buttonContainer;
public ButtonContainerHost(JPanel buttonContainer) {
super(new BorderLayout());
this.buttonContainer = buttonContainer;
add(buttonContainer);
}
#Override
public Dimension getPreferredScrollableViewportSize() {
Dimension preferredSize = buttonContainer.getPreferredSize();
if (getParent() instanceof JViewport) {
preferredSize.width += ((JScrollPane) getParent().getParent()).getVerticalScrollBar()
.getPreferredSize().width;
}
return preferredSize;
}
#Override
public int getScrollableBlockIncrement(Rectangle visibleRect, int orientation, int direction) {
return orientation == SwingConstants.HORIZONTAL ? Math.max(visibleRect.width * 9 / 10, 1)
: Math.max(visibleRect.height * 9 / 10, 1);
}
#Override
public boolean getScrollableTracksViewportHeight() {
if (getParent() instanceof JViewport) {
JViewport viewport = (JViewport) getParent();
return getPreferredSize().height < viewport.getHeight();
}
return false;
}
#Override
public boolean getScrollableTracksViewportWidth() {
return true;
}
#Override
public int getScrollableUnitIncrement(Rectangle visibleRect, int orientation, int direction) {
return orientation == SwingConstants.HORIZONTAL ? Math.max(visibleRect.width / 10, 1)
: Math.max(visibleRect.height / 10, 1);
}
}
It implements Scrollable to get full control of scrolling, does a fancy trick with tracking the viewport height to ensure the buttons expand when the space is available and adds on the width of the vertical scroll bar to the preferred width at all times. It could expand when the vertical scroll bar is visible but that looks bad anyway. Use it like this:
scrollPane = new JScrollPane(new ButtonContainerHost(buttonContainer));
It looks to me like this workaround is required because of a possible bug in javax.swing.ScrollPaneLayout:
if (canScroll && (viewSize.height > extentSize.height)) {
prefWidth += vsb.getPreferredSize().width;
}
Here extentSize is set to the preferred size of the viewport and viewSize is set to viewport.getViewSize(). This does not seem correct, AFAIK the size of the view inside the viewport should always equal the preferred size. It seems to me that the view size should be compared to the actual size of the viewport rather than its preferred size.
A simple workaround to meet your demands regarding
Is there a way to resize my JPanel when a scrollbar appears, so it
appears nicely next to my buttons?
is the use of EmptyBorder, this will let you achieve what you feel like, should happen, as shown in the image below :
I just added this line written below after this line JPanel buttonContainer = new JPanel();
ADDED LINE
buttonContainer.setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20));
Here is your code with that added line :
import java.awt.BorderLayout;
import java.awt.EventQueue;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import java.awt.GridLayout;
/**
* #author Dylan Kiss
*/
public class Demo
{
public static void main(String[] args)
{
EventQueue.invokeLater(new Runnable()
{
#Override
public void run()
{
try
{
JFrame myFrame = new JFrame("Demo");
JPanel sideBar = new JPanel();
JPanel centerPanel = new JPanel();
centerPanel.add(new JLabel("This is the center panel."));
JPanel buttonContainer = new JPanel();
buttonContainer.setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20));
JButton myButton = null;
for (int i = 0; i < 20; i++)
{
buttonContainer.setLayout(new GridLayout(20, 1, 0, 0));
myButton = new JButton("This is my button nr. " + i);
buttonContainer.add(myButton);
}
sideBar.setLayout(new BorderLayout(0, 0));
JScrollPane scrollPane = new JScrollPane(buttonContainer);
sideBar.add(scrollPane);
myFrame.getContentPane().add(sideBar, BorderLayout.WEST);
myFrame.getContentPane().add(centerPanel, BorderLayout.CENTER);
myFrame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
myFrame.pack();
myFrame.setLocationByPlatform(true);
myFrame.setVisible(true);
}
catch (Exception e)
{
e.printStackTrace();
}
}
});
}
}
You could resize the JPanel by calling setPreferredSize when the JPanel needs to be resized.
buttonContainer.setPreferredSize(Dimension d);
Related
This question already has answers here:
How to add JTable in JPanel with null layout?
(11 answers)
Closed 8 years ago.
I know this is horrible coding but I desperately need to fix this problem. I've tried multiple ways of trying to position the button but the button still stays in the top center with all the other buttons lined up after it.
import javax.imageio.ImageIO;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.Graphics;
import java.io.IOException;
import java.net.URL;
public class Template extends JFrame {
/**
* #param args
*/
public static void main(String[] args) throws IOException{
// TODO Auto-generated method stub
JFrame frame = new JFrame("The Impossible Quiz");//Construct JFrame
frame.setLayout(null);//manual setting for button placement
frame.setContentPane(new JPanel() {//sets panel as background
BufferedImage image = ImageIO.read(new URL("https://pbs.twimg.com/media/BoyFVfXIUAA0Tik.png"));//uses url image
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(image, 0, 0, 1360, 690, this);//sets image as jframe background
}
});
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//closes jframe when press exit
frame.setSize(1365, 730);//sets size of jframe
JPanel buttonpanel = new JPanel();//sets panel for all buttons
buttonpanel.setBounds(0, 0, 1460, 690);//sets placing and sizing of panel
buttonpanel.setOpaque(false);//makes panel transparent
JButton next = new JButton ("Start");//contructs correct start button
next.setBounds(10, 5, 40, 50);
buttonpanel.add(next);//adds button to panel
next.addActionListener(new ActionListener()//adds actionlistener to button
{
public void actionPerformed(ActionEvent e)
{
new Introduction();//continues to next question
}
});
JButton wrongstart = new JButton("Start!!");//constructs wrong start button
wrongstart.setSize(100, 400);//setes size of button
buttonpanel.add(wrongstart);//adds button to panel
wrongstart.addActionListener(new ActionListener()//adds actionlistener to button
{
public void actionPerformed(ActionEvent e)
{
new Wrong();//direct user to wrong panel
}
});
frame.add(buttonpanel);//adds panel to jframe
frame.setVisible(true);//sets jframe as visible
}
}
Your problem is that you're trying to use absolute positioning to position a component (your JButton) in a container (the containing JPanel) that uses FlowLayout as default, and FlowLayout completely ignores the components bounds. A quick solution is to set the JPanel's layout to null allowing for absolute positioning. A correct solution is to always avoid null layouts and absolute positioning and instead to nest JPanels, each using its own layouts, in order to create complex yet flexible and pleasing GUI's.
You're setting the JFrame contentPane's layout to null as well -- don't do that either.
And then adding a JPanel as the contentPane which uses a default FlowLayout -- don't do that. Let the contentPane's layout be BorderLayout.
Edit
For example, if we leave the contentPane alone with its BorderLayout, and add another image panel on top of it, one that uses GridBagLayout, we can easily position our JButton to the top left corner of the GUI if desired. ....
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.image.BufferedImage;
import javax.swing.*;
#SuppressWarnings("serial")
public class Template2 extends JPanel {
private static final int PREF_W = 1460;
private static final int PREF_H = 690;
private BufferedImage img;
private JButton startButton = new JButton("Start");
public Template2() {
setLayout(new GridBagLayout());
// TODO: .... read in your image here
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridx = 1;
gbc.gridy = 1;
gbc.gridwidth = 1;
gbc.gridheight = 1;
gbc.insets = new Insets(5, 10, 0, 0);
gbc.anchor = GridBagConstraints.NORTHWEST;
gbc.fill = GridBagConstraints.NONE;
gbc.weightx = 1.0;
gbc.weighty = 1.0;
add(startButton, gbc);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(PREF_W, PREF_H);
}
#Override
public void paintComponents(Graphics g) {
super.paintComponents(g);
if (img != null) {
g.drawImage(img, 0, 0, this);
}
}
private static void createAndShowGui() {
Template2 mainPanel = new Template2();
JFrame frame = new JFrame("Some Horrendous Program");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
I have a 100 by 100 grid of labels. I've got a method which creates and populates an array of Strings. The next method creates an array of labels and then adds the String (created from previous method) to the labels using the setText() method. Some of the labels contain images too. Method after that takes those JLabels and adds them to a JPanel of Grid Layout(lets call this x1). Then I've added the JPanel to a JScrollPane(x2), the JScrollPane gets added to another JPanel(x3) with an empty border and this final JPanel(x3) gets added to the JFrame. So that's how I've created the grid and I'm happy with that, I don't want to change it.
I would like to add an image to x1 - the JPanel with Grid Layout.
For this I would have to add the paintComponent method and use the drawImage() method. My question is how will Eclipse know which panel to add the image to? I's prefer not to create a separate class for x1, I did that before and it just didn't work out right and I rather not go down that incredibly frustrating road again, I'm sorry!
I have considered using a Glass Pane however I would no longer be able to see the images of the JLabels - which is really important.
I think adding the image to the background of the JPanel will be best because I also want to have a button which shows/hides the grid lines - the borders of the JLabels.
I hope I'm making sense.
Below is the code. I understand it's a lot of code in one class. I did have it in two separate classes but it just didn't work me. I find this much easier. I hope you don't mind
package roverMars;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.BorderFactory;
import javax.swing.Box;
import javax.swing.BoxLayout;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
import javax.swing.border.Border;
import javax.swing.border.EtchedBorder;
public class MenuPanel extends JPanel {
private static final long serialVersionUID = -3928152660110599311L;
public JPanel frame, textfield, buttons, cpPanel;
public JTextField Commands;
public JButton Plot, Submit, Undo;
public JLabel Position, cpLabel;
public Border loweredetched;
public JCheckBox gridLines;
public SubmitButton sub;
static final int rows = 100, columns = 100;
// ******IMAGES******
static BufferedImage North, South, West, East;
public void ImageLoader() {
try {
North = ImageIO.read(this.getClass().getResource("North.png"));
South = ImageIO.read(this.getClass().getResource("South.png"));
West = ImageIO.read(this.getClass().getResource("West.png"));
East = ImageIO.read(this.getClass().getResource("East.png"));
} catch (IOException e) {
// TODO Auto-generated catch block
System.out.println("Error occured: " + e);
e.printStackTrace();
}
}
// ******IMAGES******
public void createMenu(JPanel p) {
// Text Field Panel
Commands = new JTextField(20);
textfield = new JPanel();
textfield.setPreferredSize(new Dimension(150, 50));
textfield.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
textfield.setBackground(new Color(204, 153, 255));
textfield.add(Commands);
// Have a button next to the Text Field to clear contents.
// Might need to give the JPanel a new Flow Layout.
// Buttons Panel
buttons = new JPanel();
buttons.setPreferredSize(new Dimension(150, 250));
buttons.setLayout(new BoxLayout(buttons, BoxLayout.Y_AXIS));
buttons.setBackground(new Color(170, 051, 170));
// Create and Add buttons to the Buttons Panel
buttons.add(Box.createRigidArea(new Dimension(30, 10)));
Plot = new JButton("Plot");
Plot.setAlignmentX(Component.CENTER_ALIGNMENT);
Plot.setAlignmentY(Component.CENTER_ALIGNMENT);
buttons.add(Plot);
buttons.add(Box.createRigidArea(new Dimension(30, 10)));
Submit = new JButton("Submit");
Submit.setAlignmentX(Component.CENTER_ALIGNMENT);
Submit.setAlignmentY(Component.CENTER_ALIGNMENT);
Submit.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
sub = new SubmitButton();
sub.Submit(Commands);
cpLabel.setText("*****SET CURRENT POSITION*****");
labels[2][2].setIcon(new ImageIcon(North));
// I will be able to move the rover from here using for loops
// and if statements.
}
});
buttons.add(Submit);
buttons.add(Box.createRigidArea(new Dimension(30, 10)));
Undo = new JButton("Undo");
Undo.setAlignmentX(Component.CENTER_ALIGNMENT);
Undo.setAlignmentY(Component.CENTER_ALIGNMENT);
buttons.add(Undo);
buttons.add(Box.createRigidArea(new Dimension(30, 10)));
gridLines = new JCheckBox();
gridLines.setText("Show gridlines");
gridLines.setAlignmentX(Component.CENTER_ALIGNMENT);
gridLines.setAlignmentY(Component.CENTER_ALIGNMENT);
gridLines.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent arg0) {
// Set the colour of the JLabels array from here.
System.out.println("clicked");
}
});
buttons.add(gridLines);
buttons.add(Box.createRigidArea(new Dimension(30, 20)));
loweredetched = BorderFactory
.createEtchedBorder(EtchedBorder.RAISED);
cpLabel = new JLabel("Current position: ", JLabel.CENTER);
cpPanel = new JPanel();
cpPanel.setBackground(new Color(153, 153, 204));
cpPanel.add(cpLabel);
cpPanel.setBorder(loweredetched);
// Panel for the main window
JPanel frame = new JPanel();
frame.setPreferredSize(new Dimension(150, 350));
frame.setLayout(new BorderLayout());
frame.add(textfield, BorderLayout.NORTH);
frame.add(buttons, BorderLayout.CENTER);
// This Main Panel
p.setPreferredSize(new Dimension(350, 700));
p.setBackground(new Color(153, 153, 204));
p.setLayout(new BoxLayout(p, BoxLayout.Y_AXIS));
p.setBorder(BorderFactory.createEmptyBorder(10, 50, 10, 25));
p.add(Box.createRigidArea(new Dimension(100, 100)));
p.add(frame);
p.add(Box.createRigidArea(new Dimension(15, 15)));
p.add(cpPanel);
p.add(Box.createRigidArea(new Dimension(100, 300)));
}
// From line 142 to 202 is everything to do with creating the Grid
public void StringArray(String[][] labelText) {
int x = 1; // increment rows
for (int i = 0; i < labelText.length; i++) { // x
for (int j = 0; j < labelText.length; j++) { // y
labelText[i][j] = Integer.toString(x); // populate string
x++;
}
}
}
public void JLabelArray(JLabel[][] label, String[][] labelText) {
for (int i = 0; i < label.length; i++) { // x
for (int j = 0; j < label.length; j++) { // y
label[i][j] = new JLabel();
label[i][j].setText(labelText[i][j]);
label[i][j].setOpaque(false);
label[i][j].setBorder(BorderFactory.createLineBorder(new Color(
0, 155, 200), 1));
// label[i][j].setBackground(Color.WHITE);
}
}
}
public void populateGrid(JPanel Grid, JLabel[][] label) { // Add Labels to
// Panel,
String x1[][] = new String[rows][columns];
StringArray(x1);
JLabelArray(label, x1);
Grid.setBackground(Color.RED);
int gHeight = label.length, gWidth = label.length;
Grid.setLayout(new GridLayout(gWidth, gHeight));
for (int i = 0; i < label.length; i++) { // x
for (int j = 0; j < label.length; j++) { // y
Grid.add(label[i][j]);
}
}
}
public void createGrid(JPanel finalPanel, JPanel Grid) {
// Add Grid to Scroll Pane
JScrollPane x4 = new JScrollPane(Grid);
x4.setPreferredSize(new Dimension(600, 600)); // DO NOT DELETE THIS.
x4.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
x4.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
// Add Scroll Pane to another Panel with the Border
finalPanel.setBackground(new Color(153, 153, 204));
finalPanel.setBorder(BorderFactory.createEmptyBorder(50, 25, 50, 50));
finalPanel.add(x4);
}
// Variables for creaeteGUI method.
static MenuPanel t = new MenuPanel();
static JPanel menu = new JPanel();
static JPanel finalPanel = new JPanel();
static JPanel gridPanel = new JPanel();
static JLabel labels[][] = new JLabel[rows][columns];
public static void createGUI() {
t.createMenu(menu);
t.populateGrid(gridPanel, labels);
t.createGrid(finalPanel, gridPanel);
JFrame f = new JFrame();
f.setTitle("Project Testing");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setVisible(true);
f.setLocation(100, 100);
f.setAlwaysOnTop(true);
f.setSize(500, 500);
f.add(finalPanel, BorderLayout.CENTER);
f.add(menu, BorderLayout.WEST);
f.pack();
}
public static void main(String args[]) {
createGUI();
t.ImageLoader();
labels[2][2].setIcon(new ImageIcon(West));
}
}
Thank you so much! I really appreciate any help or suggestions :D
As you said what you need to do is to override the paintComponent method of the JPanel and put a drawImage(...) in there. So:
#Override
public void paintComponent(Graphics g)
{
//super.paintComponent(g);
g.drawImage(image, 0, 0, null);
}
Where image is an instance of the class Image that you loaded previously in the initialization code (don't load it in the paintComponent, that would be too slow and you only want to load it once).
There are 2 ways to accomplish that:
Make your own class extending JPanel and put that code there. You probably will want to create also a method setBackgroundImage(Image) that you can call from you main class to pass the image that you loaded from the disk.
Make an anonymous class, that is doing something similar but without explicitely defining a new class. To do so instead of creating the panel like this:
JPanel gridPanel = new JPanel();
do it like this:
JPanel gridPanel = new JPanel()
{
#Override
public void paintComponent(Graphics g)
{
//super.paintComponent(g);
g.drawImage(image, 0, 0, null);
}
};
Of course you must do this in the actual code (not as an static initialization) since you want to make sure that you load the image before.
Finally a couple of suggestions:
Variable names start in lower case by convention (as opposite to class names that start in upper case). You don't do this for example in the JPanel Grid argument and Comands field.
You are violating Swing's single threading rule. That is, you must call invokeLater in your main wrapping your GUI initializing code. For example look at Swing's Hello World. You can find a detailed explanation of this here.
I have a problem with showing specific component placed in JScrollPane. I have horizontal JScrollPane with GridLayout(1,0) and it contains variable number of JPanels - each containing image. It's like a preview of frames in GIF image. I use button to move among these JPanels (by changing borders and keeping index of chosen one), but I don't know how to force JScrollPane to show me JPanel if it's chosen (and center it if possible).
So I want this
force to do this:
Thanks in advance!
EDIT: almost working code with scrollRectToVisible() method
public class MiniatursPanel extends JPanel{
private int indexOfChosenFrame = 0;
private ArrayList<JPanel> frames;
private JScrollPane scrollPane;
private JPanel innerPanel;
public MiniatursPanel(){
setBorder(BorderFactory.createCompoundBorder(BorderFactory.createRaisedBevelBorder(),BorderFactory.createLoweredBevelBorder()));
setPreferredSize(new Dimension(1200,170));
setLayout(null);
}
public void initialize(){
int width = GifImageStats.getInstance().getWidth();
int height = GifImageStats.getInstance().getHeight();
int numberOfFrames = GifImageStats.getInstance().getNumberOfFrames();
frames = new ArrayList(numberOfFrames);
for (int i = 0; i < numberOfFrames; i++) {
JPanel frameBox = new JPanel();
frameBox.setLayout(new FlowLayout(FlowLayout.CENTER));
JButton button = new JButton(String.valueOf(i+1));
button.setPreferredSize(new Dimension(2*width,2*height));
button.setBackground(Color.white);
button.setFocusable(false);
frameBox.add(button);
frames.add(frameBox);
}
innerPanel = new JPanel();
innerPanel.setLayout(new GridLayout(1,0,10,10));
for (JPanel button : frames) {
innerPanel.add(button);
}
scrollPane = new JScrollPane(innerPanel);
scrollPane.setBounds(10, 10, 1180, 145);
scrollPane.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
scrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_NEVER);
highlightFrame(frames.get(0));
add(scrollPane);
}
public void nextFrame(){
if (indexOfChosenFrame == frames.size() - 1) {
unhighlightFrame(frames.get(indexOfChosenFrame));
indexOfChosenFrame = 0;
highlightFrame(frames.get(0));
}else{
unhighlightFrame(frames.get(indexOfChosenFrame));
indexOfChosenFrame++;
highlightFrame(frames.get(indexOfChosenFrame));
}
}
public void previousFrame(){
if (indexOfChosenFrame == 0) {
unhighlightFrame(frames.get(0));
indexOfChosenFrame = frames.size()-1;
highlightFrame(frames.get(indexOfChosenFrame));
}else{
unhighlightFrame(frames.get(indexOfChosenFrame));
indexOfChosenFrame--;
highlightFrame(frames.get(indexOfChosenFrame));
}
}
private void highlightFrame(JPanel frame){
Rectangle rect = frame.getBounds();
rect.setBounds(frame.getX()-550, frame.getY(), frame.getWidth()+1050, frame.getHeight());
innerPanel.scrollRectToVisible(rect);
frame.setBorder(BorderFactory.createLineBorder(Color.red,2));
}
private void unhighlightFrame(JPanel frame){
frame.setBorder(null);
}
The relevant method here is JComponent#scrollRectToVisible(Rectangle). It has to be called on the component that is in the viewport of the scroll pane. (In your case, this is the panel with the grid layout, which contains the other sub-panels).
The rectangle that is passed to this method can be the bounds of one sub-panel. In this case, the scoll pane will do the "minimum" scrolling that is necessary to make the given rectangle visible. If you want to make sure that the respective sub-panel is in the center, then you can increase the size of this rectangle - that is, you define a rectangle in a way that the desired sub-panel will be in the center.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.Rectangle;
import java.util.ArrayList;
import java.util.List;
import javax.swing.BorderFactory;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JSpinner;
import javax.swing.SpinnerNumberModel;
import javax.swing.SwingConstants;
import javax.swing.SwingUtilities;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
public class ScrollToVisible
{
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
#Override
public void run()
{
createAndShowGUI();
}
});
}
private static void createAndShowGUI()
{
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
int n = 20;
final JPanel panel = new JPanel(new GridLayout(1,0));
final List<JComponent> components = new ArrayList<JComponent>();
for (int i=0; i<n; i++)
{
JComponent component = new JLabel(String.valueOf(i), SwingConstants.CENTER);
component.setPreferredSize(new Dimension(100,100));
component.setBorder(BorderFactory.createLineBorder(Color.BLACK));
components.add(component);
panel.add(component);
}
final JScrollPane scrollPane = new JScrollPane(panel);
final JSpinner spinner = new JSpinner(new SpinnerNumberModel(0, 0, n-1, 1));
spinner.addChangeListener(new ChangeListener()
{
JComponent selectedComponent = components.get(0);
#Override
public void stateChanged(ChangeEvent e)
{
selectedComponent.setBorder(BorderFactory.createLineBorder(Color.BLACK));
int index = (Integer)spinner.getValue();
JComponent component = components.get(index);
Rectangle bounds = component.getBounds();
// This would make the component "just" visible:
//panel.scrollRectToVisible(bounds);
// This will center the component:
int cx = bounds.x + bounds.width / 2;
int w = scrollPane.getViewport().getWidth();
Rectangle r = new Rectangle(cx-w/2, bounds.y, w, bounds.height);
panel.scrollRectToVisible(r);
selectedComponent = component;
selectedComponent.setBorder(BorderFactory.createLineBorder(Color.RED));
}
});
f.getContentPane().setLayout(new BorderLayout());
f.getContentPane().add(scrollPane, BorderLayout.CENTER);
f.getContentPane().add(spinner, BorderLayout.NORTH);
f.setSize(800, 300);
f.setLocationRelativeTo(null);
f.setVisible(true);
}
}
EDIT: You should NOT use setLayout(null), and you should not do manual calls to setBounds, and you should rarely use setPreferredSize. And... when you post code that already is so close to a https://stackoverflow.com/help/mcve (or even was created from a runnable example of another post) then you should make it really runnable. It's annoying to re-insert the boilerplate code and waste some time with debugging until you realize that initialize() is not called at all...
However, change the code according to this:
private void highlightFrame(JPanel frame){
Rectangle rect = frame.getBounds();
int c = rect.x + rect.width / 2;
int w = scrollPane.getViewport().getWidth();
int x = c-w/2;
rect.setBounds(x, rect.y, w, rect.height);
innerPanel.scrollRectToVisible(rect);
frame.setBorder(BorderFactory.createLineBorder(Color.red,2));
}
private void unhighlightFrame(JPanel frame){
frame.setBorder(BorderFactory.createEmptyBorder(2, 2, 2, 2));
}
The most important thing is to make sure that the size of the components is correct, by setting an empty border with the same size as the "highlighting" border.
I'm making a GUI for a a custom source server browser with improved filtering.
This is what I have so far.
However, when I resize...
When I resize the window I want the L4D2 'filter panel' to resize to the current maximum width of the container. I also want to be able to add more of these panels in a column (such as box layout provides).
Boxlayout get's the panels to appear in a column, but it doesn't do anything for their widths.
I'm thinking I may need to override the filter panels preferred size methods so that they can retrieve the size of the parent container, but I'm not sure how to do this.
How should I approach this problem?
EDIT: Here's an example program depicting the problem.
import javax.swing.*;
import java.awt.*;
public class guiExampleProblem {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
final MyWindows wnd = new MyWindows("guiExampleProblem");
wnd.setVisible(true);
}
});
}
}
class MyWindows extends JFrame {
public MyWindows(String text) {
super(text);
setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
JPanel mainPanel = new JPanel();
mainPanel.setLayout(new BoxLayout(mainPanel, BoxLayout.Y_AXIS));
JPanel containerPanel1 = new JPanel();
JPanel containerPanel2 = new JPanel();
JPanel containerPanel3 = new JPanel();
containerPanel1.setBackground(Color.BLACK);
containerPanel2.setBackground(Color.RED);
containerPanel3.setBackground(Color.GREEN);
mainPanel.add(containerPanel1);
mainPanel.add(containerPanel2);
mainPanel.add(containerPanel3);
this.add(mainPanel);
pack();
}
}
When the window is resized, I want the panels to expand only along the x-axis, and remain at a constant height on the y-axis, however in the example the panels expand on both the x y axis.
I managed to get the desired functionality by overriding the 'filter panels' getPrefferedSize methods so that they retrieve the parent containers width and use that. Here is the code in the form of an example:
import javax.swing.*;
import java.awt.*;
public class guiExampleProblem {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
final MyWindows wnd = new MyWindows("guiExampleProblem");
wnd.setVisible(true);
}
});
}
}
class MyWindows extends JFrame {
public MyWindows(String text) {
super(text);
setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
JPanel mainPanel = new JPanel();
mainPanel.setLayout(new FlowLayout());
JPanel containerPanel1 = new JPanel() {
#Override
public Dimension getPreferredSize() {
return new Dimension(this.getParent().getWidth(),60);
}
};
JPanel containerPanel2 = new JPanel() {
#Override
public Dimension getPreferredSize() {
return new Dimension(this.getParent().getWidth(),60);
}
};
JPanel containerPanel3 = new JPanel() {
#Override
public Dimension getPreferredSize() {
return new Dimension(this.getParent().getWidth(),60);
}
};
containerPanel1.setBackground(Color.BLACK);
containerPanel2.setBackground(Color.RED);
containerPanel3.setBackground(Color.GREEN);
mainPanel.add(containerPanel1);
mainPanel.add(containerPanel2);
mainPanel.add(containerPanel3);
this.add(mainPanel);
pack();
}
}
Put the panel (with BoxLayout) that is to stretch in the CENTER of a BorderLayout -- put the panel to the right in the EAST of that BorderLayout. You have given no detail of what else you want this to do, nor any code, but this might be what you want.
--
After your solution: it seems to me that using FlowLayout here is confusing -- it lays out its components one after the other horizontally, and your trick of getting preferred size from the width of the container makes it behave differently. I also avoid getting into layout logic in my application when I can, so I looked for another way to do this and came up with:
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.FlowLayout;
import javax.swing.BoxLayout;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.WindowConstants;
public class guiExampleProblem2
{
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
#Override
public void run()
{
final MyWindows2 wnd = new MyWindows2("guiExampleProblem2");
wnd.setVisible(true);
}
});
}
}
class MyWindows2 extends JFrame
{
public MyWindows2(String text)
{
super(text);
setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
JPanel mainPanel = new JPanel();
mainPanel.setLayout(new BoxLayout(mainPanel, BoxLayout.PAGE_AXIS));
JPanel containerPanel1 = addContainedPanel(Color.BLACK, 60, 60, mainPanel);
JPanel containerPanel2 = addContainedPanel(Color.RED, 60, 60, mainPanel);
JPanel containerPanel3 = addContainedPanel(Color.GREEN, 60, 60, mainPanel);
this.add(mainPanel, BorderLayout.NORTH);
pack();
}
JPanel addContainedPanel(Color color, int width, int height, JPanel container)
{
JPanel panel = new JPanel();
panel.setPreferredSize(new Dimension(width, height));
panel.setBackground(color);
container.add(panel);
return panel;
}
}
This uses the NORTH portion of a BorderLayout (which is the default layout for a JFrame, by the way) to do the main thing you wanted -- stretch things horizontally. The BoxLayout with a page axis is intended to lay things out top-to-bottom, so I think that's less confusing for the reader. Anyway, it's another way to do it that I think uses the components - including the layout managers - more like they were intended and documented.
I couldn't explain the question in the title any better, so here goes -
I created a tiled background image. I then set the created background image to my JFrame. However, I added my JScrollPane to said background. Depending on the order I place my code in, 1 of two things will happen. When I have my JScrollPane like so -
import java.awt.BorderLayout;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.Image;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import javax.imageio.ImageIO;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.border.EmptyBorder;
public class TestingApp {
public static JFrame programFrame;
public static JLabel projectBackground;
public static JLabel projectLogo;
public static JPanel allContent;
public static JPanel fourRows;
public static JPanel centerPanel;
public static JScrollPane scrollPane;
// Tiled Background
public static void tiledBackground() {
#SuppressWarnings("serial")
class ImagePanel extends JPanel {
public Image image;
public boolean tile;
ImagePanel(Image image) {
this.image = image;
this.tile = true;
};
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
int iw = image.getWidth(this);
int ih = image.getHeight(this);
if (iw > 0 && ih > 0) {
for (int x = 0; x < getWidth(); x += iw) {
for (int y = 0; y < getHeight(); y += ih) {
g.drawImage(image, x, y, iw, ih, this);
}
}
}
}
}
}
// Making the parts for the GUI
public static void createGUI() {
java.net.URL img1 = null;
try {
img1 = new URL("https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcSE6uHn-B_qKtLZOKjQNVeIxhOaxbmfio45VMUq-mVgGKvgmeghKw");
} catch (MalformedURLException e1) {
e1.printStackTrace();
}
Image image = null;
try {
image = ImageIO.read(img1);
} catch (IOException e) {
e.printStackTrace();
}
// programFrame Title and Layout
programFrame = new JFrame("Organizer");
programFrame.setLayout(new BorderLayout());
Icon backgroundIcon = new ImageIcon(img1);
projectBackground = new JLabel(backgroundIcon);
// Logo JLabel
java.net.URL img2 = null;
try {
img2 = new URL("https://encrypted-tbn3.gstatic.com/images?q=tbn:ANd9GcTvXxBQRsJ5NgSb8VOSNU_Qfom6HRV_crcazhD6bSZUh_ux3VHbgQ");
} catch (MalformedURLException e) {
e.printStackTrace();
}
Icon logoIcon = new ImageIcon(img2);
projectLogo = new JLabel(logoIcon);
projectLogo.setBorder(new EmptyBorder(10, 10, 10, 10));
// New JPanel for GridLayouts to hold each JPanel with GridLayouts
fourRows = new JPanel(new GridLayout(1, 4));
fourRows.setLayout(new GridLayout());
fourRows.setOpaque(false);
fourRows.add(new JButton("Button"));
fourRows.add(new JButton("Button"));
fourRows.add(new JButton("Button"));
fourRows.add(new JButton("Button"));
// Makes the Initial BorderLayout (Using allContent JPanel)
allContent = new JPanel();
allContent.setLayout(new BorderLayout());
allContent.add(projectLogo, BorderLayout.NORTH);
allContent.setVisible(true);
allContent.setOpaque(false);
allContent.add(fourRows, BorderLayout.CENTER);
// Add ScrollPane
scrollPane = new JScrollPane(allContent);
scrollPane.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
scrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
scrollPane.getVerticalScrollBar().setUnitIncrement(10);
scrollPane.setOpaque(false);
scrollPane.getViewport().setOpaque(false);
// JFrame programFrame Constructors
programFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
programFrame.setLayout(new BorderLayout());
programFrame.setContentPane(new ImagePanel(image));
programFrame.add(scrollPane);
programFrame.pack();
programFrame.setVisible(true);
programFrame.setResizable(true);
programFrame.setSize(1280, 720);
programFrame.setLocationRelativeTo(null);
} // public static void createGUI() Closing
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createGUI();
} // public void run() Closing
});
}
}
It doesn't scroll on the entire JFrame, just the contentStuff, and even then, it stretches beyond to the bottom of the content to where the scroll bar isn't there, and you can't scroll.
However, when I rearrange that code, and I put my
programFrame.setContentPane(new ImagePanel(image));
BEFORE
programFrame.add(scrollPane);
I just get the repeated background image, and no content.
EDIT - Added an SSCCE
EDIT2 - Here's a solution I was trying. I tried creating an empty panel to add in the content that should update based on JFrame size. Needless to say, it didn't work. Small snippet of the edited code, nothing else was changed -
// Makes the Initial BorderLayout (Using allContent JPanel)
allContent = new JPanel();
allContent.setLayout(new BorderLayout());
allContent.add(warlordsLogo, BorderLayout.NORTH);
allContent.setVisible(true);
allContent.setOpaque(false);
allContent.add(fourRows, BorderLayout.CENTER);
int widthForCenterPanel = programFrame.getWidth();
int heightForCenterPanel = programFrame.getHeight();
// Makes a Panel to add the ScrollPane to to center is properly
centerPanel = new JPanel();
centerPanel.setOpaque(false);
centerPanel.setBounds(0, 0, widthForCenterPanel, heightForCenterPanel);
centerPanel.add(allContent);
// Add ScrollPane
scrollPane = new JScrollPane(centerPanel);
scrollPane.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
scrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
scrollPane.getVerticalScrollBar().setUnitIncrement(10);
scrollPane.setOpaque(false);
scrollPane.getViewport().setOpaque(false);
scrollPane.setBorder(new EmptyBorder(0, 0, 0, 0));
EDIT 3 - Fixed my SSCCE. If you notice when you try it, it's dependent on how large the JPanel is, not the JFrame.