Develop Reference

ImageIcon padding and/or alignment in a JButton

*edited so it might be helpful to others:
I was struggling with why an ImageIcon was being padded in a JPanel, but not in a JToolBar even though they were added in the same way, using the same file (see the folder icon):
Cutting down the code to an sscce has shown that VGR's answer below is right - it's has to be how each component deals with JButtons, rather than the layout.
This code should run, but you'll have to have "images/open.png" in the source folder.
import java.awt.Color;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.net.URL;
import javax.swing.BorderFactory;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JToolBar;
import javax.swing.border.Border;
class CandidatePanel extends JPanel{
private JPanel panel = new JPanel();
private JToolBar tb = new JToolBar();
private JButton tbButton = new JButton();
private JButton cvButton = new JButton();
public static void main(String[] args){
JFrame frame = new JFrame();
frame.add(new CandidatePanel());
frame.pack();
frame.setVisible(true);
}
public CandidatePanel(){
setLayout(new GridBagLayout());
tbButton.setIcon(new PanelHelper().createIcon("images/open.png", ""));
tb.add(tbButton);
cvButton.setIcon(new PanelHelper().createIcon("images/open.png", ""));
cvButton.setFocusPainted(false);
cvButton.setContentAreaFilled(false);
cvButton.setBorderPainted(true);
addComponents();
add(tb);
add(panel);
}
private void addComponents(){
panel.setLayout(new GridBagLayout());
int row =0;
//new row
JPanel cvButtonPanel = (JPanel)PanelHelper.addTestBorder(new JPanel(),Color.BLUE);
cvButtonPanel.add(cvButton);
cvButtonPanel.add(PanelHelper.addTestBorder(new JPanel(), Color.RED));
panel.add(tb, new GBC(1,row));
panel.add(cvButtonPanel, new GBC(1,++row));
}
}
class PanelHelper{
public static JComponent addTestBorder(JComponent comp, Color color){
Border border = BorderFactory.createLineBorder(color);
comp.setBorder(border);
return comp;
}
public ImageIcon createIcon(String path, String btnName){
URL url = getClass().getResource(path);
if(url == null)
System.err.println("\nThe "+btnName+" Icon Path Cannot Be Found: "+path);
return new ImageIcon(url);
}
}
it was just as simple as setting the button margin, as mentioned in the comments below.
button.setMargin(new Insets(0,0,0,0))

Components in JTabbedPane not showing up

I'm using a tabbed pane and can't get the tab to show the GUI that I want. I plan to have different Panel objects for each different tab so that I can setup their layouts with more versatility. Right now I don't have any listeners or functions, and am strictly trying to get the components to show up.
Edit: Code is now in the question, not a link.
Here is the code for the UI for the "General":
import javax.swing.JTabbedPane;
import javax.swing.JTable;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JFrame;
import javax.swing.JComponent;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.KeyEvent;
public class GeneralGUI extends JPanel{
public GeneralGUI() {
JPanel topPanel = new JPanel();
JPanel panel1 = new JPanel();
JPanel panel2 = new JPanel();
JLabel subjectNum = new JLabel("Subject Street #:");
JLabel subjectStreet = new JLabel("Subject Street Name:");
JTable compTable = new JTable();
JTable subjectTable = new JTable();
JButton getRPT = new JButton("Get RPT file");
JButton getOrder = new JButton("Get Order/Contract");
JButton subjectDocs = new JButton("Get Subject Docs");
JButton compDocs = new JButton("Get Comp Docs");
panel1.add(subjectNum);
panel1.add(subjectStreet);
panel1.add(compTable);
panel2.add(getRPT);
panel2.add(getOrder);
panel2.add(subjectDocs);
panel2.add(compDocs);
panel2.add(subjectTable);
topPanel.add(panel1);
topPanel.add(panel2);
topPanel.setVisible(true);
}
}
Here is the code for the tabbed pane code:
import javax.swing.JTabbedPane;
import javax.swing.ImageIcon;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JFrame;
import javax.swing.JComponent;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.KeyEvent;
public class AppraisalTabs extends JPanel {
public AppraisalTabs() {
super(new GridLayout(1, 1));
JTabbedPane tabbedPane = new JTabbedPane();
GeneralGUI genGUI = new GeneralGUI();
// JComponent panel1 = makeTextPanel("General");
tabbedPane.addTab("General", genGUI);
tabbedPane.setMnemonicAt(0, KeyEvent.VK_1);
JComponent panel2 = makeTextPanel("Docs");
tabbedPane.addTab("Docs", panel2);
tabbedPane.setMnemonicAt(1, KeyEvent.VK_2);
JComponent panel3 = makeTextPanel("Subject");
tabbedPane.addTab("Subject", panel3);
tabbedPane.setMnemonicAt(2, KeyEvent.VK_3);
JComponent panel4 = makeTextPanel("Comps");
panel4.setPreferredSize(new Dimension(410, 300));
tabbedPane.addTab("Comps", panel4);
tabbedPane.setMnemonicAt(3, KeyEvent.VK_4);
JComponent panel5 = makeTextPanel("Report");
panel4.setPreferredSize(new Dimension(800, 800));
tabbedPane.addTab("Report", panel5);
tabbedPane.setMnemonicAt(4, KeyEvent.VK_5);
//Add the tabbed pane to this panel.
add(tabbedPane);
//The following line enables to use scrolling tabs.
tabbedPane.setTabLayoutPolicy(JTabbedPane.SCROLL_TAB_LAYOUT);
}
protected JComponent makeTextPanel(String text) {
JPanel panel = new JPanel(false);
JLabel filler = new JLabel(text);
filler.setHorizontalAlignment(JLabel.CENTER);
panel.setLayout(new GridLayout(1, 1));
panel.add(filler);
return panel;
}
private static void createAndShowGUI() {
//Create and set up the window.
JFrame frame = new JFrame("Appraisal Helper");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Add content to the window.
frame.add(new AppraisalTabs(), BorderLayout.CENTER);
//Display the window.
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
//Schedule a job for the event dispatch thread:
//creating and showing this application's GUI.
SwingUtilities.invokeLater(new Runnable() {
public void run() {
//Turn off metal's use of bold fonts
UIManager.put("swing.boldMetal", Boolean.FALSE);
createAndShowGUI();
}
});
}
}
My problem is that once I run the code the tabbed pane shows up, as well as the correctly-titled tabs, but the "General" tab isn't showing anything at all. I tried to setup the buttons and everything in it but it's still blank.
Any ideas?

Use a layout in place of a component

I'd like to create a main window frame with a BorderLayout that contains other layouts as its components.
How can I add, say, a FlowLayout to my BorderLayout's NORTH position?

Here's a little program that shows you:
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.FlowLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.border.LineBorder;
public class LayoutExample {
public static void main (String[] args) {
JFrame frame = new JFrame("Frame with BorderLayout");
frame.setLayout(new BorderLayout());
JPanel flow = new JPanel();
JLabel label = new JLabel("This is a flowlayout.");
flow.setBorder(new LineBorder(Color.BLACK));
flow.setLayout(new FlowLayout());
flow.add(label);
frame.add(flow, BorderLayout.NORTH);
frame.setSize(300,300);
frame.setVisible(true);
}
}
That's how it looks like at the end:

Java GUI appears to be blank (swing + awt)

I'm having trouble getting my GUI to contain any of my JButtons or JTextField. I have two classes One "SnowballFight" class that contains my main method and frame constructor. Then I also have "GameBoard" which sets up my GUI. My problem is that my GUI appears, but appears empty.
"SnowballFight" class:
package snowballfight;
import java.awt.BorderLayout;
import javax.swing.JFrame;
import javax.swing.JButton;
import javax.swing.JTextField;
import javax.swing.JPanel;
import java.awt.Color;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class SnowballFight extends JFrame implements ActionListener{
public SnowballFight(){
setLayout(new BorderLayout(1,2));
}
public static void main(String[] args) {
SnowballFight frame = new SnowballFight();
GameBoard game = new GameBoard(frame);
}
public void actionPerformed(ActionEvent event) {
}
}
"GameBoard" class:
package snowballfight;
import java.awt.BorderLayout;
import javax.swing.JFrame;
import javax.swing.JButton;
import javax.swing.JTextField;
import javax.swing.JPanel;
import java.awt.Color;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class GameBoard extends JFrame implements ActionListener{
private JButton[][] game = new JButton[10][10];
private JTextField display = new JTextField("Welcome to the SnowBall fight!");
private Opponent[] opponents = new Opponent[4];
public GameBoard(SnowballFight frame){
JPanel panel = new JPanel();
panel.setLayout(new GridLayout( 10, 10));
for (int row = 0; row < game.length; row++) {
for (int col = 0; col < game[row].length; col++) {
game[row][col] = new JButton();
game[row][col].setBackground(Color.gray);
game[row][col].addActionListener(this);
panel.add(game[row][col]);
}
}
add(display, BorderLayout.NORTH);
add(panel, BorderLayout.SOUTH);
frame.setTitle("Snowball Fight");
frame.setSize(200, 150);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
public boolean isGameOver(){
for (int opponent = 0; opponent < opponents.length; opponent++) {
if(opponents[opponent].isSoaked() == false ){
return false;
}
}
return true;
}
public void actionPerformed(ActionEvent event) {
}
}

Not sure why there are two frames, but I think you're adding display and panel to the wrong frame.
Try changing:
add(display, BorderLayout.NORTH);
add(panel, BorderLayout.SOUTH);
to:
frame.add(display, BorderLayout.NORTH);
frame.add(panel, BorderLayout.SOUTH);

You never make the GameBoard JFrame visible
game.setVisible(true);
Some notes:
The frame SnowballFight has no apparent function
It's not necessary to extend JFrame since no functionality is being added
Read The Use of Multiple JFrames, Good/Bad Practice?

Adjusting GUI JPanels to fit

So for this program, I am trying to have a JToolBar on the left, and this spectrum panel on the right side. I am currently adding using a BorderLayout, but as you can see, the spectrum (in cyan) I add has a black border around it (the panel below). Why does it not fill the right side JPanel?
http://imgur.com/pTqMeGM
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Color;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JToolBar;
public class Spectrum extends JFrame{
/**
*
*/
private static final long serialVersionUID = 1L;
/*
*
*/
public Spectrum(){
JPanel main = new JPanel(new BorderLayout());
JPanel rightside = new JPanel();
JLabel spectrum = new JLabel("spectrum goes here");
JToolBar toolbar = new JToolBar(null, JToolBar.VERTICAL);
JButton button1 = new JButton("Icon 1");
JButton button2 = new JButton("Icon 2");
main.setBackground(Color.RED);
main.setPreferredSize(new Dimension(800, 500));
rightside.setBackground(Color.black);
spectrum.setPreferredSize(new Dimension(750,500));
spectrum.setOpaque(true);
spectrum.setBackground(Color.cyan);
toolbar.setPreferredSize(new Dimension(50, 500));
toolbar.setFloatable(false);
button1.setOpaque(true);
button2.setOpaque(true);
button1.setBackground(Color.blue);
button2.setBackground(Color.green);
toolbar.add(button1);
toolbar.add(button2);
rightside.add(spectrum);
main.add(toolbar, BorderLayout.WEST);
main.add(rightside, BorderLayout.EAST);
setContentPane(main);
pack();
setVisible(true);
}
}

I suggest you to do the following change.
main.add(rightside, BorderLayout.EAST);
to
main.add(rightside, BorderLayout.CENTER);