Question: CTRL-Z Behavior with highlighted text

When using InlineCssTextArea, when you style individual parts of the text and highlight them, then try to use CTRL-Z functionality, it’ll undo the highlighting rather than undo the text changes you entered.

A potential fix was mentioned in #761:

// plainUndoManager, or whatever that static method is called
UndoManager<PlainTextChange> um = UndoUtils.plainUndoManager(area);
area.setUndoManager(um);

The problem now is that it doesn’t appear that InlineCssTextArea is compatible with it. I’m assuming there’s an alternative version that is? Or some sort of work around would be appreciated. I’d rather not use StyleClassedTextArea in this case because it’d complicate how my project works a bit, but if I need to, I can probably make the change at some point. I just want to make there’s not an easier workaround first.

Reproducible test software:

import java.time.Duration;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;

import org.fxmisc.flowless.VirtualizedScrollPane;
import org.fxmisc.richtext.InlineCssTextArea;
import org.fxmisc.richtext.LineNumberFactory;
import org.reactfx.Subscription;

public class SyntaxTest extends Application {

	private static final String[] KEYWORDS = new String[] { "[[test]]" };

	private static final String sampleCode = "this is a syntax [[test]]";

	public static void main(String[] args) {
		launch(args);
	}

	@Override
	public void start(Stage primaryStage) {
		InlineCssTextArea textArea = new InlineCssTextArea();
		
		 Subscription cleanupWhenNoLongerNeedIt = textArea
	                .multiPlainChanges()
	                .successionEnds(Duration.ofMillis(100))
	                .subscribe(ignore -> computeHighlighting(textArea, KEYWORDS, "coral"));

		textArea.setParagraphGraphicFactory(LineNumberFactory.get(textArea));
		
		textArea.replaceText(0, 0, sampleCode);

		Scene scene = new Scene(new StackPane(new VirtualizedScrollPane<>(textArea)), 600, 400);
		primaryStage.setScene(scene);
		primaryStage.setTitle("Syntax Test");
		primaryStage.show();
		
		primaryStage.setOnCloseRequest(event ->{
			cleanupWhenNoLongerNeedIt.unsubscribe();
		});
	}

	public static void computeHighlighting(InlineCssTextArea textArea, String[] keywords, String colorFillCode) {
		String text = textArea.getText();
		
		textArea.setStyle(0, textArea.getLength(), "");
		
		for (int i = 0; i < keywords.length; i++) {
			String keyword = keywords[i];
			
			if (keyword.trim().isEmpty() || keyword.startsWith("//")) continue;
			
			boolean containsKeywords = true;
			int lastEnd = 0;
			
			while(containsKeywords) {
				int start = text.indexOf(keyword, lastEnd);
				int end = start + keyword.length();
				
				if (start >= 0) {
					textArea.setStyle(start, end, "-fx-fill: " + colorFillCode + ";");
					lastEnd = end;
				}else {
					containsKeywords = false;
				}
			}
		}
	}
}

[JordanMartinez]

Ah, figured it out. The issue is that the change type should be List<PlainTextChange> because of #695

So, the code is actually:

UndoManager<List<PlainTextChange>> um = UndoUtils.plainTextUndoManager(textArea);
textArea.setUndoManager(um);

After that, it stopped undoing the syntax highlighting.

[ekartoyev]

Regarding the issue-starter’s comment:

I’d rather not use StyleClassedTextArea

I’d like to point out, I ran into the undo-highlight issue in StyleClassedTextArea too, so switching to that probably wouldn’t have resolve it.

But changing the undo-manager did the job. Thank you for the recipe!