Java Community | Help. Code. Learn.•6mo ago

How to add blank lines to the end of a Document?

I'm working on a text editor and it needs to copy some text from one JTextArea to another at the same line, but when one adds a line I can't copy it over with the code I'm using because the document doesnt have enough Elements. My code is

        addCaretListener(new CaretListener() {
            public void caretUpdate(CaretEvent ce) {
                JTextComponent comp = (JTextComponent)ce.getSource();
                int pos = comp.getCaretPosition();
                Element root = comp.getDocument().getDefaultRootElement();
                lineNum = root.getElementIndex(pos);
                Element line = root.getElement(lineNum);
                try {
                    String text = comp.getDocument().getText(line.getStartOffset(), line.getEndOffset() - line.getStartOffset());
                    CodeDoc document = (CodeDoc) other.getDocument();
                    text = ((CodeView) comp).hasAssm ? CodeView.fromAssm(text) : CodeView.toAssm(text);
                    document.replace(document.getDefaultRootElement().getElement(lineNum).getStartOffset(), document.getDefaultRootElement().getElement(lineNum).getEndOffset(), text, null);
                } catch (BadLocationException e) {
                    throw new RuntimeException(e);
                }
            }
        });

        addCaretListener(new CaretListener() {
            public void caretUpdate(CaretEvent ce) {
                JTextComponent comp = (JTextComponent)ce.getSource();
                int pos = comp.getCaretPosition();
                Element root = comp.getDocument().getDefaultRootElement();
                lineNum = root.getElementIndex(pos);
                Element line = root.getElement(lineNum);
                try {
                    String text = comp.getDocument().getText(line.getStartOffset(), line.getEndOffset() - line.getStartOffset());
                    CodeDoc document = (CodeDoc) other.getDocument();
                    text = ((CodeView) comp).hasAssm ? CodeView.fromAssm(text) : CodeView.toAssm(text);
                    document.replace(document.getDefaultRootElement().getElement(lineNum).getStartOffset(), document.getDefaultRootElement().getElement(lineNum).getEndOffset(), text, null);
                } catch (BadLocationException e) {
                    throw new RuntimeException(e);
                }
            }
        });

30 Replies

JavaBot•6mo ago

⌛ This post has been reserved for your question.

Hey @blockgoblin31! Please use /close or the Close Post button above when your problem is solved. Please remember to follow the help guidelines. This post will be automatically closed after 300 minutes of inactivity.

TIP: Narrow down your issue to simple and precise questions to maximize the chance that others will reply in here. 💤 Post marked as dormant

This post has been inactive for over 300 minutes, thus, it has been archived. If your question was not answered yet, feel free to re-open this post or create a new one. In case your post is not getting any attention, you can try to use /help ping. Warning: abusing this will result in moderative actions taken against you.

blockgoblin31OP•6mo ago

Bump

JavaBot•6mo ago

💤 Post marked as dormant

This post has been inactive for over 300 minutes, thus, it has been archived. If your question was not answered yet, feel free to re-open this post or create a new one. In case your post is not getting any attention, you can try to use /help ping. Warning: abusing this will result in moderative actions taken against you.

blockgoblin31OP•6mo ago

Bump

dan1st•6mo ago

So you want to copy from a specific part of the document to another? Do you want to overwrite the entire line?

blockgoblin31OP•6mo ago

yes, they should effectively be mirroring each other constantly, its effectively two different formats of the same text I have copying working except on the bottom line of the document, there it doesnt work and spams errors

dan1st•6mo ago

Can you show the errors? Do both documents always have the same number of elements before copying?

blockgoblin31OP•6mo ago

No, that’s what I’m trying to fix, I don’t know how to add a new element of a blank line if the element doesn’t exist. It’s a BadLocationException

dan1st•6mo ago

Does it happen in document.replace? Which library are you using?

blockgoblin31OP•6mo ago

Yes, when that calls Document.remove It’s a custom class that I didnt include in the post for… some reason I’ll get that now

dan1st•6mo ago

Can you show the stack trace?

blockgoblin31OP•6mo ago

CodeView.java

StackTrace.txt

dan1st•6mo ago

What is CodeDoc, specifically line 102?

blockgoblin31OP•6mo ago

CodeDoc is also in CodeView.java I really need to clean that part up thats just calling PlainDocument.remove

dan1st•6mo ago

Can you use a debugger and find out what offs and len is where it throws the exception?

JavaBot•6mo ago

💤 Post marked as dormant

This post has been inactive for over 300 minutes, thus, it has been archived. If your question was not answered yet, feel free to re-open this post or create a new one. In case your post is not getting any attention, you can try to use /help ping. Warning: abusing this will result in moderative actions taken against you.

blockgoblin31OP•6mo ago

with both TextAreas blank it's running with offs 0 and len 1(Checking the elements theres one element containing a "\n")

dan1st•6mo ago

which have a \n? and do you get an exception in that case?

blockgoblin31OP•6mo ago

The document being replaced is just a new PlainDocument, but looking at the elements it has this. And yes I still get the exception.

blockgoblin31OP•6mo ago

I wonder if its an off by one from .getEndOffset()? and yes it was now the only problem is if they have different numbers of elements

dan1st•6mo ago

what exactly is str here? "\n"?

blockgoblin31OP•6mo ago

I think it should be blank, I can double check quickly after I finish testing this yes, it is "\n"

dan1st•6mo ago

and the error happens in that exact situation where offs is 0, len is 1 and str is "\n"?

blockgoblin31OP•6mo ago

Sorry I missed your message, I just solved the bad location exception problem, now I'm getting this stacktrace

message.txt

dan1st•6mo ago

Does it still happen with offs being 0?

blockgoblin31OP•6mo ago

no, that only happens if the Document I'm currently editing has more lines than the other document and I have one of those lines selected, it happens before the .replace call its the document.getDefaultRootElement().getElement(lineNum) call returning null

dan1st•6mo ago

What about that: In this case, just add it at the last line?

blockgoblin31OP•6mo ago

And moving the index back by one and putting \n at the start of the text if the line doesnt exist worked I tried that earlier but used the wrong length ty

JavaBot•6mo ago

💤 Post marked as dormant

This post has been inactive for over 300 minutes, thus, it has been archived. If your question was not answered yet, feel free to re-open this post or create a new one. In case your post is not getting any attention, you can try to use /help ping. Warning: abusing this will result in moderative actions taken against you.

JavaBot•6mo ago

Post Closed

This post has been closed by <@501514065068294154>.

Gaming

Programming

How to add blank lines to the end of a Document?

Did you find this page helpful?