How to use RichTextFX

Question

How can I use RichTextFX to highlight a portion of a textarea? Do I need to add the JAR file to my project library?

Please walk me through the whole procedure .

Answer 1

Yes you have to add the jar to the buildpath of your project.

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

  import org.fxmisc.richtext.CodeArea;
  import org.fxmisc.richtext.LineNumberFactory;
  import org.fxmisc.richtext.StyleSpans;
  import org.fxmisc.richtext.StyleSpansBuilder;
  import org.fxmisc.richtext.demo.JavaKeywords;

  public class MainFX extends Application {
private CodeArea codeArea = new CodeArea();
private String exampleString = "This is a WARNING for an INFO! Please stay tuned";

private static final String[] KEYWORDS = new String[] { "INFO", "WARNING" };
/* This keyword could get another color by css */
private static final String[] DEBUG_KEYWORD = new String[] { "DEBUG" };

private static final String KEYWORD_PATTERN = "\\b("
        + String.join("|", KEYWORDS) + ")\\b";
private static final String PAREN_PATTERN = "\\(|\\)";
private static final String BRACE_PATTERN = "\\{|\\}";
private static final String BRACKET_PATTERN = "\\[|\\]";
private static final String SEMICOLON_PATTERN = "\\;";
private static final String STRING_PATTERN = "\"([^\"]|\\\")*\"";
private static final Pattern PATTERN = Pattern.compile("(?<KEYWORD>"
        + KEYWORD_PATTERN + ")" + "|(?<PAREN>" + PAREN_PATTERN + ")"
        + "|(?<BRACE>" + BRACE_PATTERN + ")" + "|(?<BRACKET>"
        + BRACKET_PATTERN + ")" + "|(?<SEMICOLON>" + SEMICOLON_PATTERN
        + ")" + "|(?<STRING>" + STRING_PATTERN + ")");

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

@Override
public void start(Stage primaryStage) {
    primaryStage.setTitle("Richtext demo");
    String stylesheet = JavaKeywords.class.getResource("java-keywords.css")
            .toExternalForm();
    IntFunction<String> format = (digits -> " %" + digits + "d ");
    codeArea.setParagraphGraphicFactory(LineNumberFactory.get(codeArea,
            format, stylesheet));
    codeArea.textProperty().addListener((obs, oldText, newText) -> {
        codeArea.setStyleSpans(0, computeHighlighting(newText));
    });
    codeArea.replaceText(0, 0, exampleString);
    Scene scene = new Scene(new StackPane(codeArea), 600, 400);
    scene.getStylesheets().add(stylesheet);
    primaryStage.setScene(scene);
    primaryStage.show();
}

/**
 * For Content highlighting
 */
private static StyleSpans<Collection<String>> computeHighlighting(
        String text) {
    Matcher matcher = PATTERN.matcher(text);
    int lastKwEnd = 0;
    StyleSpansBuilder<Collection<String>> spansBuilder = new StyleSpansBuilder<>();
    while (matcher.find()) {
        String styleClass = matcher.group("KEYWORD") != null ? "keyword"
                : matcher.group("PAREN") != null ? "paren" : matcher
                        .group("BRACE") != null ? "brace" : matcher
                        .group("BRACKET") != null ? "bracket" : matcher
                        .group("SEMICOLON") != null ? "semicolon" : matcher
                        .group("STRING") != null ? "string" : null; /* never happens */
        assert styleClass != null;
        spansBuilder.add(Collections.emptyList(), matcher.start()
                - lastKwEnd);
        spansBuilder.add(Collections.singleton(styleClass), matcher.end()
                - matcher.start());
        lastKwEnd = matcher.end();
    }
    spansBuilder.add(Collections.emptyList(), text.length() - lastKwEnd);
    return spansBuilder.create();
}
}

And the CSS for DEBUG:

.debug {-fx-fill: #8346F2;-fx-font-weight: bold;}

For more info, see this demo.