I used the UndoManager to add undo and redo functionality to my JTextPane. However, it saves the text every time text is entered, so it undos to the last letter. How can I make it undo to the last word?
http://java-sl.com/tip_merge_undo_edits.html That's an example of such merging edits.
Use UndoableEdit#addEdit(). If you make non-whitespace edits stick together on the undo stack (by absorbing each other through this method) and whitespace edits too, then the next undo will act on the last work or last whitespace gap, which is what you want.
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I am trying to find out how to only move 4 spaces forward in JTextArea, when pressing the 'tab' key on the keyboard. Currently it moves forward 8 spaces.
I've done some reading on Styles in Java and came across setLeftIndent() however this isn't what I need. I have thought about using a key listener so anytime 'tab' is pressed in JTextArea, it only moves forwards by 4 spaces (keybindings).
I would appreciate any advices.
Thanks.
You can use the setTabSize(...) method of JTextArea:
textArea.setTabSize( 4);
I have done a GUI in Java with a JTextArea. It is filled with the content of a file.
When I select words with the mouse on the textarea, a new frame pops up on which I do some operations on the selected words. To do these operations, I need to know the line number of the selected text...
Does someone know how to get the line number?
(I look to some methods on the classes JTextArea and MouseListener, but i dont know how to do that...)
Thanks ;)
Check out the Text Utilities. The getLineAtCaret() method is close to what you need. It uses the offset of the caret to get the line number. In you case you will need to use the start offset of the selected text.
I'm having a problem with JTextArea (not a problem though).
I want to create my own college program, one of the function is to write down and save a list of homework each day. It's text area having the main function here, which is to type everything my lecturer said. But text area will act like Windows original notepad, which is not keeping the indentation. So my questions are:
How do I have a function where I press the SHIFT+TAB key it will decrease indentation by one.
If number 1 is possible, then how do my program have behaviour when I press ENTER key, it will have a new line with previous indentation? Just like NetBeans and other IDE.
Edited: I'm a beginner in Java, in truth, I'm making this program while studying Java in my college.
How do I have a function where I press the SHIFT+TAB key it will decrease indentation by one.
You need to use key bindings to listen for the user typing Shift+Tab.
If number 1 is possible, then how do my program have behavior when I press ENTER key, it will have a new line with previous indentation? Just like NetBeans and other IDE.
Use a similar piece of logic to capture the Enter key presses. Then, check the previous line in the editor and count the number of tab characters preceding the text. Output a similar number at the start of the new line.
you could use Javascript/jquery for indenting by inserting empty space of specific line. while pressing your hot key combination call function to insert five spaces on your cursor.
I want to make an auto completion textfield, which replaces the input with the first hit and selects the part which wasn't entered by the keyboard yet. To do so, I'll have to count the chars typed (or deleted). How can I filter if the KeyEvent is a printable Char (and not SHIFT f.e.)?
Look at https://swingx.dev.java.net/
This lib is already have great autocomplete text fields
i prefer to do it with the KeyListener
Well, a KeyListener is the wrong tool for the job.
If you really want to write your own code then you should start with a DocumentListener. Every time text is added or removed from the text field you will be notified. Then you can implement your auto completion code.
I have this problem:
The text "ABCD\r\nEFGHJ" loaded from a file is matched with java regex "EFGH". Matcher object of course says start of the matched string is in position 6. The matcher counts \r \n as two positions.
I put the original text in a AWT TextArea Component and then call select(6,10) to highlight the area which was matched. Guess what... it starts highlighting from 'F' letter. One position forward than it should...
If more than 1 pair of crlf precedes matched area then highlighting moves even more forward than it should.
Anyone has any simple solution?
Simple solution: remove all \r from the text... :-P
Not as stupid as it sounds, unless you have inconsistent end of lines (it can happen) and want to keep them unchanged... And that's probably what the component does anyway.
I cant mess with the text because it is protocol data and \r and \n characters have semantics that dont have to do with display or line separation. I just want a component that will treat each one input character separately and treat it as one displayed and counted, no matter how it is displayed.
If the \r\n are consistent, you can remove the \r's before running the regex, then replace them before handing off to whatever is next. Or change a copy, if that works better. This way, your regex finds the position in a way consistent with what AWT is expecting.