Develop Reference

How to align text position for two different components?

I am trying to align the position of text within a JTextArea and a JButton, but with everything I tried, either nothing happens, or the alignment is still slightly off.
Here is what is looks like:
(You can see with the highlighted option that the JButton (center) is slightly lower than the two JTextAreas on either side.)
Here is some code:
categoryFile[i][j] = tempButton;
categoryFile[i][j].setBackground(Color.white);
categoryFile[i][j].setForeground(Color.black);
categoryFile[i][j].setOpaque(true);
categoryFile[i][j].setFocusable(false);
categoryFile[i][j].setBorderPainted(false);;
categoryFile[i][j].setVerticalAlignment(SwingConstants.TOP);
categoryFile[i][j].setPreferredSize(new Dimension(500,10));
categoryFile[i][j].addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
openPDFWithOptions(filePath,fileName);
}
});
JPanel listRow = new JPanel();
listRow.setBackground(Color.white);
listRow.setLayout(new BorderLayout());
listRow.setPreferredSize(new Dimension(800, 40));
JTextArea category = new JTextArea(fileElements[0]);
category.setEditable(false);
JTextArea parent = new JTextArea(fileElements[1]);
parent.setEditable(false);
listRow.add(parent,BorderLayout.WEST);
listRow.add(categoryFile[i][j],BorderLayout.CENTER);
listRow.add(category,BorderLayout.EAST);
categoryLists[i].add(listRow,c);
Right now I am using categoryFile[i][j].setVerticalAlignment(SwingConstants.TOP) to change the position of the JButton, which ALMOST works. I've also tried changing the vertical alignment of the JTextAreas, but nothing changed.
How can I align the text within these components?

Quickest way to fix this would probably be to just add some padding on the 1st and third columns to set all the text to the same height. See Jpanel Padding

Java - Swing - TextArea - scrollbar

I want to have a textArea to display results that can be scrolled. The scrollbar doesn't appear even though I set it to VERTICAL_SCROLLBAR_ALWAYS
What Am I doing wrong??
void addPlayerPanel(JFrame gameFrame) {
JPanel playerPanel = new JPanel();
// automatically added to contentPane with gameFrame.add()
gameFrame.add(playerPanel, BorderLayout.CENTER);
playerPanel.setBorder(new TitledBorder(new EtchedBorder(), "Registered players"));
// text are to show registered players
JTextArea display = new JTextArea(5, 40);
display.setEditable(true); // set textArea to editable
display.setLayout(new FlowLayout(FlowLayout.CENTER, 0, 0));
JScrollPane scroll = new JScrollPane(display);
scroll.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
// Add Text area
playerPanel.add(scroll);
playerPanel.add(display);
}

You're adding both the JScrollPane AND it's display to the GUI -- DON'T do that. Add just the JScrollPane. It holds the display and that is what you need.
So change:
playerPanel.add(scroll);
playerPanel.add(display);
to
playerPanel.add(scroll);
// playerPanel.add(display);
Question: why are you setting the layout manager of your JTextArea? That really makes little sense.

Java Swing panel layered on top with centered text

I'm making a simple Jeopardy-esque game:
using Java Swing. It's obviously a JFrame with a JPanel in it and buttons in rows.
Now what I need is to add a layered panel with a centered and wrapped text in it:
Which I can remove later. I already tried using JTextPane and JTextArea and JPanel, none of those want to even display. The best effect I have achieved with AWT Panel, it does display but I can't center or wrap text in it.
Here's some code for which I appologise, I would usually try to make it short and readable but since it's not working I don't know what to do with it to make ti look better:
JLabel questionLabel = new JLabel(questionList.get(randomNumber).getQuestion(), SwingConstants.CENTER);
Font font = new Font("Arial", Font.PLAIN, 20);
//------------------JTextPane--------------------
JTextPane questionPane = new JTextPane();
questionPane.setForeground(Color.WHITE);
questionPane.setSize(gameWidth, gameHeight);
questionPane.setText(questionList.get(randomNumber).getQuestion());
questionPane.setFont(font);
questionPane.setEditable(false);
//------------------AWT panel--------------------
Panel awtPanel = new Panel();
awtPanel.setBackground(Color.blue);
awtPanel.setSize(game.getWidth(),game.getHeight());
Label labelQuestion = new Label("<html>" + questionList.get(randomNumber).getQuestion() + "</html>", Label.CENTER);
labelQuestion.setFont(font);
awtPanel.setForeground(Color.white);
awtPanel.add(labelQuestion);
//------------------JPanel-----------------------
JPanel layeredPanel = new JPanel();
layeredPanel.setBackground(Color.blue);
layeredPanel.setSize(game.getWidth(),game.getHeight());
JLabel jLabelQuestion = new JLabel("<html>" + questionList.get(randomNumber).getQuestion() + "</html>", SwingConstants.CENTER);
jLabelQuestion.setFont(font);
layeredPanel.setForeground(Color.WHITE);
layeredPanel.add(jLabelQuestion, BorderLayout.CENTER);
game.getLayeredPane().add(layeredPanel, JLayeredPane.DEFAULT_LAYER);
try {
Thread.sleep(3000);
} catch (InterruptedException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
button.setEnabled(false);
font = new Font("Arial", Font.PLAIN, 16);
button.add(jLabelQuestion, BorderLayout.CENTER);
button.setDisabledIcon(new ImageIcon(source.getScaledInstance(gameWidth/4, gameHeight/5, java.awt.Image.SCALE_SMOOTH)));
questionList.remove(randomNumber);
logger.info(questionList.size());
game.getLayeredPane().remove(layeredPanel);
UPDATE: I chnaged to SWT rather than Swing, and I use the StackLayout with a few Composites in it, and just change between them as I see fit.

You can generally solve issues like this with a JLabel.
I would recommend encapsulating the above grid in the BorderLayout.CENTER of another pane, perhaps a new content pane. Then, add the caption to BorderLayout.NORTH.
As a more tangible example,
private void createContent() {
this.getContentPane().setLayout(new BorderLayout());
//establish the panel currently set as center, here labeled "everythingElse"
this.getContentPane().add(everythingElse, BorderLayout.CENTER);
//Create a JLabel with your caption
JLabel jlbl = new JLabel("Question");
//format that caption, most details being rather obvious, but most importantly:
jlbl.setHorizontalAlignment(SwingConstants.CENTER); //keeps text centered
this.getContentPane().add(jlbl, BorderLayout.NORTH); //add it to the top of the panel
//...other cleanup operations...
}
The issue with grid panes is that they have a limited tolerance for the number of components visible in them. If you overload one, it won't show. For BorderLayout panes, you can easily swap new items into and out of them.
For efficiency's sake, I might recommend compiling this JLabel as a final somewhere else in your code, and holding onto it for when you need it. This way, you will also dodge overhead from repeatedly creating the label object.
Lastly, avoid AWT whenever you can. It's been deprecated for an excess of ten years, and if you do use it you will run into numerous critical problems involving heavyweight and lightweight component incompatibilities. If you intend to use another windowing kit, consider implementing the new standard, JavaFX, with a JFXPane-- it's much more tolerant of HTML syntax, as well.

Button inside text box

My code shows a button inside a textbox, but when the input value changes, the size of the text box also changes. That I don't like. Is there any solution such that the textbox size remains fixed? Or any other idea on how to create a button inside textbox?
The following is my code:
JPanel panel = new JPanel();
panel.setLayout( new FlowLayout(FlowLayout.CENTER, 0, 0) );
panel.add(textField);
panel.add(button);
panel.setBackground( textField.getBackground() );
panel.setBorder( textField.getBorder() );
textField.setBorder(null);

Try a BorderLayout and add the textfield at BorderLayout.CENTER and the button at BorderLayout.EAST.

I tried your code, and it seemed to work fine for me, with a slight modification. It may be that panel is resizing itself, not textField. Try wrapping panel in another JPanel to force its shape.
JPanel panel = new JPanel();
JPanel outerPanel = new JPanel();
panel.setLayout( new FlowLayout(FlowLayout.CENTER, 0, 0) );
panel.add(textField);
panel.add(button);
panel.setBackground( textField.getBackground() );
panel.setBorder( textField.getBorder() );
textField.setBorder(null);
outerPanel.add(panel);

Your example appears to be the second alternative discussed in the article Component Border. Instead, you may want to install() a ComponentBorder, a third alterative described later in the same article.

Is there any solution such that the textbox size remains fixed?
I'm guessing you are creating the JTextField like:
JTextField textField = new JTextField();
In this case the text field size changes as you add text to it.
Instead you should use:
JTextField textField = new JTextField(10);
and the text field will remain a constant size an hold a minimum of 10 characters before scrolling.

Use a different Layout, or try absolute positioning

problems with scrolling a java TextArea

All,
I am running into an issue using JTextArea and JScrollPane. For some reason the scroll pane appears to not recognize the last line in the document, and will only scroll down to the line before it. The scroll bar does not even change to a state where I can slide it until the lines in the document are two greater than the number of lines the textArea shows (it should happen as soon as it is one greater).
Has anyone run into this before? What would be a good solution (I want to avoid having to add an extra 'blank' line to the end of the document, which I would have to remove every time I add a new line)?
Here is how I instantiate the TextArea and ScrollPane:
JFrame frame = new JFrame("Java Chat Program");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Container pane = frame.getContentPane();
if (!(pane.getLayout() instanceof BorderLayout)) {
System.err.println("Error: UI Container does not implement BorderLayout.");
System.exit(-1);
}
textArea = new JTextArea();
textArea.setPreferredSize(new Dimension(500, 100));
textArea.setEditable(false);
textArea.setLineWrap(true);
textArea.setWrapStyleWord(true);
JScrollPane scroller = new JScrollPane(textArea);
scroller.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
pane.add(scroller, BorderLayout.CENTER);
Here is the method I use to add a new line to textArea:
public void println(String a)
{
textArea.append(" "+a+"\n");
textArea.setCaretPosition(textArea.getDocument().getLength());
}
Thanks for your help,
Jonathan
EDIT: Also, as a side note, with the current code I have to manually scroll down. I assumed that setCaretPosition(doc.getLength()) in the println(line) method would automatically set the page to the bottom after a line is entered... Should that be the case, or do I need to do something differently?

The problem is textArea.setPreferredSize(new Dimension(500, 100));
Remove that. Set the perferredSize of the scrollpane or the size of your frame instead

Is this a solution? I didn't test it, so please don't kill me.
scroller.getVerticalScrollBar().setValue(pane.getVerticalScrollBar().getMaximum());