How to use HTML in Swing - java

I have a bit of an unusual problem:
I have a swing label that updates for "Used letters" in the game Hangman. I have it declared like this:
used = new JLabel(" Used: ");
But then i have another area in the code where i add onto it. Here:
used.setText(used.getText() + lUsed + " , ");
Now when the user enters letters, it updates the label and the letters are added, but if you enter enough, they push the rest of the contents of the frame out of view. The label expands the WEST side of my borderlayout so much that everything else get's pushed and then some times cut off the application window.
Is there a good way to use HTML to make it so that it word wraps the text and does not change the panel (what it's contained in) size?
GridLayout c = new GridLayout(rows,0);
westPanel = new JPanel(c);
westPanel.add(guessedPanel);
westPanel.add(usedPanel);
frame.getContentPane().add(westPanel, BorderLayout.WEST);
How it's laid out ^^

For a more general solution for those coming from Google, you can add HTML to Swing components very easily, as long as the content being added starts and
ends with the proper HTML tags.
For example, you may insert HTML text into a JLabel such that:
label.setText("<html> Text </html>");
You could color center it and underline the first letter like this:
label.setText("<html><center><u>T</u>ext</center></html>");
Here's a good tutorial on how to use HTML in your Swing components.
--
For your specific solution, you can simply use HTML when adding text to the label. Instead of using used.getText() you should store the text in a String somewhere (that does not enclose the opening and closing HTML tags), and update that String, in order to be able to effectively manage the opening and closing HTML tags. So it could go something like this
String text; // Earlier in the code
...
text += ("<br> " + lUsed);
used.setText("<html>" + text + "</html>")
Among other things, you could attempt setting a preferred or maximum size of the label so that it is not allowed to become to large. Also, you could make the label a text panel or text area of some kind instead, which would automatically support word wrapping, scrolling, and other features that you may want.
Here's a guide on how to use JTextAreas.

Specify a width in styles for the body tag of the HTML. See Text Wrap in JOptionPane for an example.

Related

Opening a file into a JLabel

I want to create a program which allows the user to input a file name and then it shows everything written in the file in a JLabel, I have managed to find/create code which allows the user to input the name of the file and then show the contents of the file in the console but I couldn't find a way to show everything from the text file in a JLabel.
Is there a way to do this? As some people have told me that it is not possible to do this.
Yes...it is possible but as already mentioned you would be far better off using the JTextArea or similar component instead and most likely save yourself some grief.
Although a JLabel is basically designed for a single string line of text it does allow for that text to be wrapped within HTML tags therefore allowing for basic HTML/CSS to format that same text. The trick then is to read each line of a desired text file into a single string variable formatting that string as you append each line read and, by formatting, I mean adding:
A Title;
Line Breaks;
Indenting;
Left Marginal Padding;
Line Wrapping;
Bold, Italics, Underlining;
Fonts, Font Style, Font Sizes, and even Font Colors;
Text alignments like Left, Center, Right, and Justify;
etc, etc, etc.
A JLabel doesn't recognize the usual line breaks you're already familiar with like "\n" or "\r\n" or even System.lineSeparator();. It will however deal with the HTML Line Break tag of <br> but only if the text being applied to the JLabel is wrapped within HTML. Here is an example of a two line JLabel text:
String txt = "<html>This is line one.<br>This is line two.</html>";
jLabel1.setText(txt);
Ultimately your JLabel would look something like this:
Notice in the code line above that the String text starts with <html> and ends with </html>. Any text between these two tags is considered to be wrapped in HTML. You will also notice the <br> tag within the string which forces the Line Break so as to create two lines.
A JLabel is very limited to what it can do and without HTML it can't really do anything bullet listed above and display a text file within a JLabel like this:
You will of course notice the Scrollbar in the above image. Yet another problem with the JLabel, it won't display Scrollbars if needed. You need to place the JLabel into a JScrollPane to have this feature since there may very well be files that are going to exceed the boundaries of your JLabel so you need to also consider this. Simple enough, not the end of the world.
The method provided below will read in the supplied text file and display it within the supplied JLabel. It will automatically wrap everything into HTML, Provide the title, Left pad all the text by 10 pixels, Line Wrap the text, handle Line Breaks, and take care of basic Indentation:
public void displayFileInJLabel(JLabel label, String filePath) {
try {
// Try With Resources (will auto close the reader).
try (BufferedReader reader = new BufferedReader(new FileReader(filePath))) {
/* We use StringBuilder to build our HTML Wrapped
string to display within the JLabel. */
StringBuilder sb = new StringBuilder();
// Get the width of our supplied JLabel
int w = label.getWidth();
/* Calculations for determininfg Line Wrap.
The (w / 4) is a modifiable offset. */
String width = String.valueOf((w - (w / 4)));
/* Deal with Line Wrap (JLabels don't do this) and
set up Left Padding. */
sb.append("<html><body style='width: ").append(width).append("px; padding:10px;'>");
/* Apply the Title Center of JLabel, Blue Color Text,
and Bold Font Style.The size of the text is determined
by the <h1> and </h1> tags. */
sb.append("<center><h1><font color=blue><b>").append(filePath).append("</b></font></h1></center><br>");
// Read in File Lines one at a time.
String line;
while((line = reader.readLine()) != null) {
/* Deal with multiple whitespaces (basic indenting etc) since HTML
doesn't deal well with more than a single whitespace. */
line = line.replaceAll("\\s{4}", " ");
/* Deal with line breaks. JLabels won't deal with them since
it is designed for a single line of text. We therefore
apply the HTML Line Break tag (<br>)at the end of each
text file line to take care of this business. */
line+= "<br>";
sb.append(line);
}
// Apply the closing tags to finish our HTML Wrapping.
sb.append("</body></html>");
/* Set the formated HTML text to the JLabel */
label.setText(sb.toString());
}
}
catch (IOException ex) {
Logger.getLogger("displayFileInJLabel() Method").log(Level.SEVERE, null, ex);
}
}
If you remove all the commenting then it really isn't that much code but there is yet more to do. To build the form sample displayed above
Create a new JFrame Form;
Set it's DefaultCloseOperation property to DISPOSE;
Set it's AlwaysOnTop property to true;
before the Form is displayed set it's SetLocationRelativeTo
property to null;
Place a JScrollPane into the JFrame form. Have it take up the
entire size of Form;
Place a JLabel into the JScrollPane. Have it take up the entire size
of the JScrollPane;
Set the JLabel's Background color to White;
Set the JLabel's Opaque property to true;
Set the JLabel's HorizontalAlignment to LEFT;
Set the JLabel's VerticalAlighnment to TOP;
Make sure the JLabel Text property is empty (nothing);
Copy and Paste the displayFileInJLabel() method into an
accessible place. Within your JFrame Form Class will do if you like.
Place a call to the displayFileInJLabel() method within the
JFrame's ComponentResized event, something like this:
displayFileInJLabel(jLabel1, "C:\\MyFiles\\LoremIpsum.txt");
Better to have a class member variable hold the file path to view rather than hard coding it then fill this member variable in the Form's Class Constructor that would have a String Type parameter.
It's all a matter of what you really want to do. Using a JTextArea is still a better idea.

How can I make it so a JLabel only displays the first line of text?

Take a look at this picture:
This is a JLabel with a height that is not allowed to vary. However when there is too much text to fit in its given size it attempts to display both lines. I do not want this, how do I make it so that only the first line up to the "in new" is displayed?
Why not make it scrollable? This way you can maintain the preferred size, and at the same time display the info when it's needed. You just have to put the JLabel inside a JScrollPane:
JScrollPane scroller = new JScrollPane(yourJLabel,
JScrollPane.VERTICAL_SCROLLABAR_AS_NEEDED,
JScrollPane.HORIZONTAL_SCROLLABAR_AS_NEEDED);
The solution was to not use html (ie, "<html>" inside of the string) for it was what was causing the lines to warp when too long. All bolding and monospacing had to be done without using html.

JPanel to display large amount of text

I'm currently searching for a method to display an introduction for my program. Every part of the program has it's own instructions that are several lines long. At the end of each line there is \n\n for formatting.
It would be cool if the font size could adjust automatically to the panel size and if the text could be centered. I tried TextLayout and adding the text to a simple JLabel but none of this displays the text correctly.
Any suggestions on how to accomplish this task?
You can also use HTML formatting in the JLabel text. All you need to do is surround the text with <html> and </html>, set the font size with a <font> element, and replace every \n with <br>.
String formatted = text.replace("\n", "<br>");
formatted = "<html><font size='9'>" + formatted + "</font></html>";
JLabel label = new JLabel(formatted);
See How to Use HTML in Swing Components.
I agree with #Josh M, you should try using a JTextArea with a JScrollPane. Alternatively, if you do not expect too much GUI manipulation by the user, you could manually format the text using basic stuff like newlines ('\n') and tabs('\t').
You can give a columns count to your JTextField like this:
JTextField textField = new JTextField("I Have a Big Text and I want show it now!", 40);
40 is the column index which means the text has more columns for showing data in default now.
Another way you could do this is to use JTextArea

Scroll through JLabel held in JScrollPane

I have a JScrollPane that holds a JLabel using the following code:
//Create TEXT LOG JPanel
textLogPane = new JScrollPane(logLabel);
textLogPane.setPreferredSize(textLogPaneDim);
//textLogPane.setOpaque(true);
textLogPane.setBorder(BorderFactory.createLineBorder(Color.BLACK));
textLogPane.getViewport().setBackground(Color.DARK_GRAY);
The JLabel, logLabel, is represented by a string with an HTML encoding using for carriage returns. I display certain images based on the contents of certain lines and I would like to be able to scroll the JScrollPane, textLogPane, to show that line whenever I am displaying that graphic. I know the contents of the line that I want to display but I can't seem to figure out how to get it to scroll down(or up) to the relevant line.
If need be I can change to something other than a JLabel as long as I can keep the HTML encoding and have it look just like multiple lines of text.
Sorry if this is a repeat I tried searching but couldn't find any results.
Thanks
You can do some custom maths and use scrollRectToVisible() in your viewport. I don't know how to compute the rect of a specific line in your JLabel. A better solution would be to stick your strings into a JList instead, perhaps with a custom renderer for the html, and use
list.ensureIndexIsVisible(list.getSelectedIndex());
You don't use "carriage returns" in HTML, you use "br" tags.
I would suggest you should probably be using a JTextPane for multiline text. I also find it easier to not use HTML, but instead to add strings with attributes. You can also insert icons into a JTextPane.
Read the section from the Swing tutorial on Using Text Components for a working example.

Restrict number of lines in html JLabel

I have a JLabel that needs to display some html-formatted text. However, I want to restrict this to being 4 lines long (and if so, provide a button to see everything).
So far, I've tried setting the maximum size manually or via a layout manager. However, both of these solutions can cause part of a line to be displayed.
edit: To add a little more details, I need to force 4 lines even when respecting line wrapping correctly, resizing components, and changing font sizes. I've considered handling resize/fontsize changes by replacing the label with a new one that fits correctly.
JLabel seems to handle incomplete tags well, so I could probably do something like a binary search on the input string finding which character would cause it to go over the 4 line limit (using FontMetric to determine how many pixels 4 lines would be), and then replacing an existing label with the new one. The big downside to this approach is that I need to run the computation every time the user resizes the panel or changes fonts (and it feels like a dirty dirty hack).
Add the JLabel to a JScrollPane as set the scrollpane with a reasonable preferred size. Scrollbars will appear a necessary.
I don't know of any absolute solution to the questions since I doubt you can define what a "line" is. One line of text may be font 12 and another 24. I don't know of any way to calculate the height of each given line.
Even if you did use a ComponentListener to handle the componentResized() event I'm not sure you can come up with a reasonable algorithm to to calculate the exact width/height of of a 4 line display.
I would try running through the String of text and removing all text after the third "\n"
String shortenText(String oldtext){
String newText = "";
for(int i=0;i<3;i++){
newText += oldtext.substring(0,oldtext.indexOf("\n"));//adds one line to String
oldtext = oldtext.substring(indexOf("\n")+1);//shorten old string to prepare for next iteration
}
return newText;
}
You may also want to try the same algorithm, except strip of <p> and <br> tags as well...
If you know the values of the possible tags just switch the text from "\n" to "<br>" or any tag you need
Hey, I found a way that works. The framework I'm working with allows me to create a listener for font size changes. In this listener, I determine what the new max size of the label is (getFontMetrics(font).getHeight() * 4) and then re-set the maximum height on the label to this and then relayout everything. This even handles the word wrap case well. I'm guessing that someone could do nasty things with silly HTML input, but this covers the 99% case pretty well.

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