Develop Reference

Huge space between my JSlider and text underneath

I'm currently working on a media player for java, and with the power of VLCJ I was working on implementing an equalizer adjust window. There will be 11 vertical sliders with a JLabel underneath them indicating the hZ band and the dB level of the band. However, the slider keeps adding a huge gap between itself and the JLabel. I tried stacking just two JLabels on top of each other and there's barely a gap at all. My code is below. (The return equalizer stuff hasn't been implemented yet. I just want a basic UI working before I start adding in the functionality)
import java.awt.GridLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JSlider;
import uk.co.caprica.vlcj.player.Equalizer;
public class VideoEQFrame {
public VideoEQFrame() {
//constructor
}
public Equalizer show() {
JFrame frame = new JFrame("Effects");
JPanel panel = new JPanel();
JPanel sliders= new JPanel();
JPanel gainObjects = new JPanel(new GridLayout(2, 0, 2, 0));
JSlider gainS = new JSlider(JSlider.VERTICAL, -12, 12, 0);
gainS.setMajorTickSpacing(2);
gainS.setPaintTicks(true);
gainS.setToolTipText("Adjust the gain");
JLabel gainL = new JLabel("Text");
gainObjects.add(gainS);
gainObjects.add(gainL);
sliders.add(gainObjects);
panel.add(sliders);
frame.add(panel);
frame.setSize(new Dimension(600, 300));
//frame.setResizable(false);
frame.setVisible(true);
Equalizer eq = new Equalizer(0);
return eq;
}
}

You are using GridLayout to lay the slider and the text label. That means that they will both occupy the same height. So because the slider has bigger height, the height of the label also adjusts to this height. Try using another LayoutManager like BorderLayout, like so:
import java.awt.BorderLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JSlider;
public class VideoEQFrame {
public VideoEQFrame() {
//constructor
}
public void show() {
JFrame frame = new JFrame("Effects");
JPanel panel = new JPanel();
JPanel sliders= new JPanel();
JPanel gainObjects = new JPanel(new BorderLayout());
JSlider gainS = new JSlider(JSlider.VERTICAL, -12, 12, 0);
gainS.setMajorTickSpacing(2);
gainS.setPaintTicks(true);
gainS.setToolTipText("Adjust the gain");
JLabel gainL = new JLabel("Text");
gainObjects.add(gainS, BorderLayout.CENTER);
gainObjects.add(gainL, BorderLayout.PAGE_END);
sliders.add(gainObjects);
panel.add(sliders);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(panel);
frame.pack();
frame.setLocationRelativeTo(null);
//frame.setResizable(false);
frame.setVisible(true);
// Equalizer eq = new Equalizer(0);
// return eq;
}
public static void main(final String[] args) {
new VideoEQFrame().show();
}
}

Dynamically changing the size of JFrame when exposed to different screen resolutions

So for a school project I made a grade book in java. When creating the gui I used hardcoded values in the setBounds() methods. Now this worked when I had a 1024×768 screen resolution it looked alright, but when I got a new laptop and it had a 4k screen it looked super small when I ran the program.
So my question would be is there a way to dynamically change the size of the Jframe and all of the associated objects on the frame so it matches the resolution of the screen?
I know that you can get the screen resolution from this
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
double width = screenSize.getWidth();
double height = screenSize.getHeight();
but I do not know what would be the best way to do this.

Taking your approach as example and taking this answer and this tutorial as base, here you have the clues:
import java.awt.Dimension;
import java.awt.Rectangle;
import java.awt.Toolkit;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;
import javax.swing.JFrame;
public class Q1 extends JFrame {
public static void main(String[] args) {
Q1 frame = new Q1();
frame.setSize(300, 300);
frame.setMinimumSize(new Dimension(300, 300));
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
public Q1() {
this.addComponentListener(new ComponentAdapter() {
public void componentResized(ComponentEvent e) {
// This is only called when the user releases the mouse button.
System.out.println("componentResized");
}
});
}
#Override
public void validate() {
resize();
super.validate();
};
private void resize() {
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
double width = screenSize.getWidth();
double height = screenSize.getHeight();
System.out.println(width + "," + height);
}
}
This will print the size of the screen when your resize the frame, so you just need to add an if/else in the resize method to make frame bigger
OUTPUT
1366.0,768.0
1366.0,768.0
componentResized
1366.0,768.0
1366.0,768.0
componentResized
1366.0,768.0
1366.0,768.0
componentResized

A layout manager is an object that implements the LayoutManager
interface* and determines the size and position of the components
within a container. Although components can provide size and alignment
hints, a container's layout manager has the final say on the size and
position of the components within the container.
See the example I found using layout managers.Hope you get some idea.THe original author is here Set a layout manager like BorderLayout and then define more specifically, where your panel should go: like
MainPanel mainPanel = new MainPanel();
JFrame mainFrame = new JFrame();
mainFrame.setLayout(new BorderLayout());
mainFrame.add(mainPanel, BorderLayout.CENTER);
mainFrame.pack();
mainFrame.setVisible(true);
puts the panel into the center area of the frame and lets it grow automatically when resizing the frame.See below example for full usage:
import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.GridBagLayout;
import java.awt.GridLayout;
import javax.swing.BorderFactory;
import javax.swing.Box;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class TestLayoutManagers {
private JPanel northFlowLayoutPanel;
private JPanel southBorderLayoutPanel;
private JPanel centerGridBagLayoutPanel;
private JPanel westBoxLayoutPanel;
private JPanel eastGridLayoutPanel;
private final JButton northButton = new JButton("North Button");
private final JButton southButton = new JButton("South Button");
private final JButton centerButton = new JButton("Center Button");
private final JButton eastButton = new JButton("East Button");
private final JButton westButton = new JButton("West Button");
public TestLayoutManagers() {
northFlowLayoutPanel = new JPanel(new FlowLayout(FlowLayout.CENTER));
southBorderLayoutPanel = new JPanel(new BorderLayout());
centerGridBagLayoutPanel = new JPanel(new GridBagLayout());
eastGridLayoutPanel = new JPanel(new GridLayout(1, 1));
Box box = Box.createHorizontalBox();
westBoxLayoutPanel = new JPanel();
northFlowLayoutPanel.add(northButton);
northFlowLayoutPanel.setBorder(BorderFactory.createTitledBorder("Flow Layout"));
southBorderLayoutPanel.add(southButton);
southBorderLayoutPanel.setBorder(BorderFactory.createTitledBorder("Border Layout"));
centerGridBagLayoutPanel.add(centerButton);
centerGridBagLayoutPanel.setBorder(BorderFactory.createTitledBorder("GridBag Layout"));
eastGridLayoutPanel.add(eastButton);
eastGridLayoutPanel.setBorder(BorderFactory.createTitledBorder("Grid Layout"));
box.add(westButton);
westBoxLayoutPanel.add(box);
westBoxLayoutPanel.setBorder(BorderFactory.createTitledBorder("Box Layout"));
JFrame frame = new JFrame("Test Layout Managers");
frame.setLayout(new BorderLayout()); // This is the deafault layout
frame.add(northFlowLayoutPanel, BorderLayout.PAGE_START);
frame.add(southBorderLayoutPanel, BorderLayout.PAGE_END);
frame.add(centerGridBagLayoutPanel, BorderLayout.CENTER);
frame.add(eastGridLayoutPanel, BorderLayout.LINE_END);
frame.add(westBoxLayoutPanel, BorderLayout.LINE_START);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
TestLayoutManagers testLayoutManagers
= new TestLayoutManagers();
}
});
}
}

Changing JScrollPane height in Swing

I failed to change the height of JPanel or JScrollPane to make more lines to appear, I used GridLayout. It seems that, every component in it should have the same size even when I use setSize(). Should I use another layout?
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
public class Main {
private JFrame mainFrame;
private JLabel headerLabel;
private JLabel statusLabel;
private JPanel controlPanel;
private imagePanel image;
JTextField textField = new JTextField(20);
public Main() throws IOException{
prepareGUI();
}
class imagePanel extends JPanel {
private static final long serialVersionUID = 1L;
public void paint(Graphics g) {
try {
BufferedImage image = ImageIO.read(new File("file.jpg"));
g.drawImage(image, 170, 0, null);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
public static void main(String[] args) throws IOException{
Main swingControlDemo = new Main();
swingControlDemo.showEventDemo();
}
private void prepareGUI(){
mainFrame = new JFrame("Java SWING Examples");
mainFrame.setSize(400,500);
GridLayout gridlayout = new GridLayout(4, 1);
gridlayout.setVgap(1);
mainFrame.setLayout(gridlayout);
headerLabel = new JLabel("",JLabel.CENTER );
statusLabel = new JLabel("",JLabel.CENTER);
JScrollPane scroller = new JScrollPane(statusLabel, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
mainFrame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent windowEvent){
System.exit(0);
}
});
controlPanel = new JPanel();
controlPanel.setLayout(new FlowLayout());
image = new imagePanel();
image.setLayout(new FlowLayout());
// mainFrame.add(headerLabel);
mainFrame.add(image);
mainFrame.add(controlPanel);
mainFrame.add(scroller);
mainFrame.setVisible(true);
}
private void showEventDemo(){
headerLabel.setText("Control in action: Button");
JButton okButton = new JButton("reload");
JButton submitButton = new JButton("Submit");
JButton cancelButton = new JButton("Cancel");
okButton.setActionCommand("reload");
submitButton.setActionCommand("Submit");
cancelButton.setActionCommand("Cancel");
okButton.addActionListener(new ButtonClickListener());
submitButton.addActionListener(new ButtonClickListener());
cancelButton.addActionListener(new ButtonClickListener());
controlPanel.add(okButton);
controlPanel.add(submitButton);
//controlPanel.add(cancelButton);
controlPanel.add(textField);
System.out.println("---------------------");
mainFrame.setVisible(true);
}
private class ButtonClickListener implements ActionListener{
public void actionPerformed(ActionEvent e) {
String command = e.getActionCommand();
if( command.equals( "reload" )) {
statusLabel.setText(convertToMultiline("Line1\nLine2\nLine3\nLine4\nLine5\nLine6\nLine7\nLine8\nLine9\nLine2\nLine3\nLine\nLine2\nLine3\nLine\nLine2\nLine3\nLine\nLine2\nLine3\nLine\nLine2\nLine3\nLine\nLine2\nLine3\nLine\nLine2\nLine3\nLine"));
}
else {
statusLabel.setText("Submit Button clicked.");
}
}
}
public static String convertToMultiline(String orig)
{
return "<html>" + orig.replaceAll("\n", "<br>");
}
}
The GUI need to look like this

I want to remove the large vertical gaps between the componets, and the jLabel should use that space
Well in your comment you say you want the label to use the space. But in your picture you show the text area with all the space. How can we answer a question when you give us conflicting requirements? Be specific and accurate when describing a problem.
In any case, the default layout of a JFrame is a BorderLayout so you would probably start with that.
Then the component that you want to grow/shrink as the frame is resized should be added to the CENTER of the frame.
Then you create a second panel to contain your other components. This panel would then be added to either the PAGE_START or PAGE_NORTH of the frame depending on your exact requirement.
The layout manager of this panel can then be whatever your want. Maybe a GridLayout, or a GridBagLayout or a vertical BoxLayout.
Read the section from the Swing tutorial on Layout Managers for more information and working examples. The key point is you create nest panels each with a different layout manager to achieve your layout.

Java - combobox height changes with frame height

I have a frame which contains a vertical toolbar with a combobox and some buttons. The combobox takes up the maximum height it can in the toolbar. Why? And how to solve this? Is there a way to fix the size of the combobox?
The code:
import java.awt.BorderLayout;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JToolBar;
import javax.swing.border.BevelBorder;
public class Clipping extends JPanel {
public Clipping()
{
setLayout(new BorderLayout());
JToolBar toolbar = new JToolBar(JToolBar.VERTICAL);
CreateToolBarButtons(toolbar);
toolbar.setFloatable(false);
toolbar.setBorder(new BevelBorder(BevelBorder.RAISED));
add(toolbar, BorderLayout.WEST);
}
private static void CreateToolBarButtons(JToolBar toolbar)
{
String[] cboList = {"Line", "Polygon"};
JComboBox cboDraw = new JComboBox(cboList);
JButton btnClip = new JButton("Set clip area");
JButton btnClear = new JButton("Clear");
toolbar.add(cboDraw);
toolbar.addSeparator();
toolbar.add(btnClip);
toolbar.addSeparator();
toolbar.add(btnClear);
}
public static void main(String[] args)
{
CreateFrame();
}
private static void CreateFrame()
{
JFrame frame = new JFrame("Clipping");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new Clipping());
frame.setSize(500,500);
frame.setVisible(true);
}
}

JToolbar uses a BoxLayout and JComboBox has an issue with it. See this question for a solution. Rather than creating a subclass, try to just setMaximumSize on the combo box with the height that you like.

Java JScrollPane- Multiple components

I'm trying to add 2 images inside the JScrollPane. the first image is a background and the second one overlap the first one. The problem shows only the second image when i run my program!
please help
ImageIcon ii = new ImageIcon("mini_map.png");
JLabel label1=new JLabel(ii);
Icon icon = new ImageIcon("Mg.gif");
JLabel label2 = new JLabel(icon);
JScrollPane jsp=new JScrollPane();
jsp.getViewport().add(label1);
jsp.getViewport().add(label2 );

JViewport is a single-child container, you can't add two components.
To achieve an overlap (that is stack components in z-direction) in any container, you'r mostly on your own, the built-in support is poor. Either have to manage them in LayeredPane (as mentioned already) or try OverlapLayout

Put both labels in the same panel and add it to the JScrollPane:
ImageIcon ii = new ImageIcon("mini_map.png");
JLabel label1=new JLabel(ii);
Icon icon = new ImageIcon("Mg.gif");
JLabel label2 = new JLabel(icon);
JPanel pContainer = new JPanel();
pContainer.add(label1);
pContainer.add(label2);
JScrollPane jsp=new JScrollPane(pContainer);

If you want to have components on top of each other use a layered pane.

This is how I would do it for your particular problem.
Since you say you have one image which serves the role of a background, thus I would override paintComponent() like in BackgroundPanel below.
This way you have a panel which serves as a background only. To it you can add any type of component, in your case a JLabel with an ImageIcon.
This way you have an effect of one being over another and you are still able to use layout manager to control where your components are.
If your problem is more complex or you want to generally set Components one over another then do as all are saying here ---> use JLayeredPane. Note that if you use JLayeredPane sadly layout managers will not help you since it doesn't respects them. You will have to proceed similarly to a situation when you use a null manager, i.e. setBounds() for components.
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.RenderingHints;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.SwingUtilities;
public class PaintInScroll
{
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
#Override
public void run()
{
try
{
Image backgroundImage = new ImageIcon(new URL(
"http://www.jvsearch.com/adidocs7_images/JAVAORANGE.JPG")).getImage();
BackgroundPanel bP = new BackgroundPanel(backgroundImage);
bP.setLayout(new BorderLayout());
bP.setPreferredSize(new Dimension(500, 500));
JLabel label = new JLabel(new ImageIcon(new URL(
"https://blogs.oracle.com/theplanetarium/resource/thumb-java-duke-guitar.png")));
bP.add(label, BorderLayout.CENTER);
JScrollPane scrollPane = new JScrollPane(bP);
scrollPane.setPreferredSize(new Dimension(300, 400));
JPanel contentPane = new JPanel();
contentPane.add(scrollPane);
JFrame f = new JFrame();
f.setContentPane(contentPane);
f.setSize(800, 600);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setVisible(true);
}catch(MalformedURLException ex)
{
Logger.getLogger(PaintInScroll.class.getName()).log(Level.SEVERE, null, ex);
}
}
});
}
}
class BackgroundPanel extends JPanel
{
private Image image;
public BackgroundPanel(Image image)
{
this.image = image;
}
private static final long serialVersionUID = 1L;
#Override
protected void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2.drawImage(image, 0, 0, this.getWidth(), this.getHeight(), null);
}
}
NOTE: Images are URLs thus i-net connection is required to run the example.
EDIT1: Example showing how to use JLayeredPane with use of layout managers for each layer.
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;
import java.awt.event.ComponentListener;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JLayeredPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.SwingUtilities;
public class PaintInScrollRespectingLayoutManagers extends JPanel
{
private static final long serialVersionUID = 1L;
private JLayeredPane layeredPane;
private JLabel imageContainer = new JLabel();
private JButton infoB = new JButton("i");
private JScrollPane scrollPane;
public PaintInScrollRespectingLayoutManagers(ImageIcon image)
{
super();
this.imageContainer.setIcon(image);
scrollPane = new JScrollPane(imageContainer);
scrollPane.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
scrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED);
scrollPane.setPreferredSize(new Dimension(125, 90));
JPanel iSPP = new JPanel();//image scroll pane panel
iSPP.setOpaque(false);
iSPP.add(scrollPane);
JPanel iBP = new JPanel();//info button panel
iBP.setOpaque(false);
iBP.add(infoB);
this.layeredPane = new JLayeredPane();
layeredPane.add(iSPP, new Integer(50));
layeredPane.add(iBP, new Integer(100));
this.setLayout(new BorderLayout());
this.add(layeredPane, BorderLayout.CENTER);
this.add(new JButton("A button"), BorderLayout.SOUTH);
layeredPane.addComponentListener(layeredPaneCL);
setPreferredSize(new Dimension(300, 300));
}
private ComponentListener layeredPaneCL = new ComponentAdapter()
{
#Override
public void componentResized(ComponentEvent e)
{
super.componentResized(e);
System.out.println("componentResized");
for(Component c : layeredPane.getComponents())
c.setSize(layeredPane.getSize());
}
};
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
#Override
public void run()
{
try
{
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new PaintInScrollRespectingLayoutManagers(new ImageIcon(new URL(
"http://www.prodeveloper.org/wp-content/uploads/2008/10/stackoverflow-logo-250.png"))));
frame.pack();
frame.setVisible(true);
}catch(MalformedURLException ex)
{
Logger.getLogger(PaintInScrollRespectingLayoutManagers.class.getName()).log(Level.SEVERE, null, ex);
}
}
});
}
}
NOTE 2: The only reason that the scroll panes have setPrefferedSize is so you can see the scrollbars. Otherwise do not use it let the layout take care of controlling scroll pane.