Q: How to apply multiple styles at the same time ?

[Scoty]

Hello,
I am trying to make a simple XML editor. This is the part of the code where I am trying to style the main CodeArea of the app, to have code highlight:

public static void setCurCodeArea(CodeArea newCodeArea) {

        newCodeArea.textProperty().addListener(new ChangeListener<String>() {
            @Override
            public void changed(ObservableValue<? extends String> observable, String oldText, String newText) {

                StyleSpansBuilder<Collection<String>> spansBuilder = new StyleSpansBuilder<>();

                //make the "<" and ">" blue
                Pattern arrows = Pattern.compile("\\<|\\>");
                addSpanStyle(spansBuilder, newText, arrows, "arrow");

                //make text between <>  brown
                Pattern tags = Pattern.compile("\\<(.*?)\\>");
                addSpanStyle(spansBuilder, newText, tags, "tag");

                newCodeArea.setStyleSpans(0, spansBuilder.create());
            }
        });

        curCodeArea = newCodeArea;
    }

    private static void addSpanStyle(StyleSpansBuilder<Collection<String>> spansBuilder, String newText, Pattern pattern, String spanClass) {
        Matcher matcher = pattern.matcher(newText);
        int lastKwEnd = 0;
        while (matcher.find()) {
            spansBuilder.add(Collections.emptyList(), matcher.start() - lastKwEnd);
            spansBuilder.add(Collections.singleton(spanClass), matcher.end() - matcher.start());
            lastKwEnd = matcher.end();
        }
        spansBuilder.add(Collections.emptyList(), newText.length() - lastKwEnd);
    }

And this is part of the exception StackTrace.

Caused by: java.lang.StringIndexOutOfBoundsException: String index out of range: -2968
    at java.lang.String.substring(String.java:1918)
    at org.fxmisc.richtext.StyledText.subSequence(StyledText.java:59)
    at org.fxmisc.richtext.Paragraph.subSequence(Paragraph.java:153)
    at org.fxmisc.richtext.Paragraph.restyle(Paragraph.java:180)
    at org.fxmisc.richtext.EditableStyledDocument.setStyleSpans(EditableStyledDocument.java:281)
    at org.fxmisc.richtext.StyledTextArea.setStyleSpans(StyledTextArea.java:444)
    at xmltool.UIBean$1.changed(UIBean.java:37)
    at xmltool.UIBean$1.changed(UIBean.java:23)
    at com.sun.javafx.binding.ExpressionHelper$SingleChange.fireValueChangedEvent(ExpressionHelper.java:176)
    at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:80)
    at org.reactfx.inhibeans.binding.ObjectBinding.release(ObjectBinding.java:45)
    at org.reactfx.inhibeans.binding.ObjectBinding$$Lambda$69/1971275683.close(Unknown Source)
    at org.reactfx.Hold.lambda$multi$34(Hold.java:23)
    at org.reactfx.Hold$$Lambda$75/1047103664.close(Unknown Source)
    at org.fxmisc.richtext.StyledTextArea.replaceText(StyledTextArea.java:496)
    at org.fxmisc.richtext.EditActions.replaceText(EditActions.java:127)
    at xmltool.MainController.fileOpenByString(MainController.java:126)
    at xmltool.utils.UIHelperUtil.loadOpenFiles(UIHelperUtil.java:130)
    at xmltool.utils.UIHelperUtil.restoreState(UIHelperUtil.java:118)
    at xmltool.Main.initialization(Main.java:93)
    at xmltool.Main.start(Main.java:85)
    at com.sun.javafx.application.LauncherImpl$8.run(LauncherImpl.java:837)
    at com.sun.javafx.application.PlatformImpl$7.run(PlatformImpl.java:335)
    at com.sun.javafx.application.PlatformImpl$6$1.run(PlatformImpl.java:301)
    at com.sun.javafx.application.PlatformImpl$6$1.run(PlatformImpl.java:298)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl$6.run(PlatformImpl.java:298)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.access$300(WinApplication.java:39)
    at com.sun.glass.ui.win.WinApplication$4$1.run(WinApplication.java:112)
    ... 1 more

I guess I am not applying the multiple styles in a proper way...

[TomasMikula]

The StyleSpans instance you are trying to apply in

newCodeArea.setStyleSpans(0, spansBuilder.create());

has twice the length of the text, since each invocation of your addSpanStyle method adds style spans of total length equal to the length of the text. Each call to spansBuilder.add(style, length) adds a style span with the given length. In your case, the lengths total to twice the text length of the text.