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.
Related
I have a JTextArea that picks up text from another JTextArea and displays that text as seen in this image:
I want the JTextArea to wrap the line from where rahul is written as in previous image.
And below is the code from my smaller JTextArea from which the text is shown in the larger JTextArea.
SimpleDateFormat sdf=new SimpleDateFormat("HH:mm");
String str=MainFrame.un+" ("+sdf.format(new Date())+") :"+txtSend.getText();
DataServices.send(runm+":"+str); // for sending this to its socket
txtView.append("\n\n\t\t\t\t\t"+str);
txtSend.setText("");
txtSend.requestFocus(true);
i want it to start from where rahul is written just below that not from left edge of text area
This is not supported in a JTextArea. A JTextArea is used for displaying simple text.
You could use a JTextPane. It allows you to control attributes of the text and one of the attributes could be the left indent. So you can set the paragraph attributes for a single line to be indented by a specific number of pixels.
So instead of using tabs to indent the text you would just need to set the left indent when you add the line of text.
Note also that a JTextPane does not implement an append method so you would need to create your own by adding text directly to the Document using:
textPane.getDocument.insertString(...);
So the basic logic would be:
StyledDocument doc=(StyledDocument)textPane.getDocument();
doc.insertString(...);
SimpleAttributeSet attrs = new SimpleAttributeSet();
//StyleConstants.setFirstLineIndent(attrs, 50);
StyleConstants.setLeftIndent(attrs, 50);
doc.setParagraphAttributes(0,doc.getLength(),attrs, false);
This will change the indent of the line of text you just added to the text pane.
I want to read large file like 10-15k lines to jtextarea.
Beside that, I also have to add every line to List and to highlight some specific lines in jtextarea.
What I tried for now is, I pass file into FileReader into BufferedReader. Inside my SwingWorker, in doBackground method I call:
while ((line = br.readLine()) != null) {
textArea.append(line);
textArea.append(System.getProperty("line.separator"));
list.add(line);
highlightLine(lineNumber);
}
When I run the program, and I choose file and open read process, it instantly loads up to 700 lines, then program slows down and loads like 10 lines per second.
Another idea I have is to, read a whole file with JTextComponent read method (which seems to setText faster then append every line), and then, read again whole file or iterate through every line in jtextarea and add that line to List and also highlight, which I think is not very efficient. What do you suggest me?
I want to read large file like 10-15k lines to jtextarea
Use the read(...) method of the JTextArea class to read the entire file directly into the text area.
I also have to add every line to List
Why do you need two copies of the text? If you need a line of data you can get the text from the text area:
int start = textArea.getLineStartOffset(...);
int end = textArea.getLineEndOffset(...);
String text = textArea.getDocument().getText(...);
to highlight some specific lines
Use a Highlighter to highlight the lines after they have been loaded into the text area.
Highlighter highlighter = textArea.getHighlighter();
highlighter.addHighlight(...);
Again you can get the offsets of the line using code from above.
Use the Document interface. it is the model that holds the data of the view-component that is JTextArea. You can get it from JTextArea with getDocument or you can use one of the classes that already implement Document: AbstractDocument, DefaultStyledDocument, HTMLDocument, PlainDocument. Then add your Document of choice to JTextArea with setDocument.
You can use insertString(int offset, String str, AttributeSet a) to add content to the Document. It also supports several listeners and you could consider a using render(Runnable r) to style it the document.
I haven't tried this but I would suggest putting all the file contents into a String, then use the setText(String text) method to set the text of the JTextArea all at once.
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.
I have a JTextPane which displays colored text . I use the followong piece of code to get text from JTextPane.
String temp = pane.getDocument().getText(0,pane.getDocument().getLength());
However when i try to set the temp variable content to pane again,
pane.select(0,pane.getDocument().getLength());
pane.replaceSelection(temp);
by this way i lose the color and get white text. Is there anyway where i can maintain the color of text without copying the content to clipboard.
Please help.
Actually it depends on EditorKit you use. The first part returns text (with styled info) of the selected fragment. E.g. in the RTFEditorKit it would be rtf content of the document's fragment.
The second part is not correct. Replace selection can't process the content properly. I guess in case of the RTFEditorKit it would be all the text with formatting inserted in the pane.
I would use
pane.setText(temp);
instead. If you need to insert the styled fragment use kit.read(...) passing the temp in the call
You can try the Kit as alternative of the default RTFEditorKit and see what happens
UPDATE: Sorry original comment was incorrect a bit. The code should be
pane.getEditorKit().read(
new StringReader(temp),
pane.getDocument(),
pane.getDocument().getLength())
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