Share My Creation MarkCraft - Markdown Editor

Toley · Feb 18, 2026

Thank you will be very useful. I have this error when compiling in B4J

B4J Version: 10.30
Parsing code.    (0.04s)
    Java Version: 19
Building folders structure.    (0.02s)
Running custom action.    (0.05s)
Compiling code.    (0.23s)
Compiling layouts code.    (0.02s)
Organizing libraries.    (0.00s)
Compiling generated Java code.    Error
src\b4j\example\b4xmainpage.java:1645: error: method _webscroll in class b4xmainpage cannot be applied to given types;
    _webscroll(null, s);    // lazy way to call sub
    ^
  required: String
  found:    <null>,String
  reason: actual and formal argument lists differ in length
1 error

javac 19.0.2

Edit: Happens only on release on debug it run fine thank you.

zed · Feb 18, 2026

Replace the Java code with this one.

Code: Copy

#if java
import javafx.scene.web.*;
import javafx.event.*;

public void setAlertHandler(WebView wv) {

 wv.getEngine().setOnAlert(new EventHandler<WebEvent<String>>(){

            @Override
            public void handle(WebEvent<String> arg0) {          
               caller(arg0.getData());
            }

        });
}
public void caller(String s){
    try{
    _webscroll(s);    // lazy way to call sub
    } catch (Exception e) {
    }
}
#End If

_webscroll(null,s); It asked for two parameters, but we only passed one.

PaulMeuris · Feb 19, 2026

Nice work, will there be a light mode?

zed · Feb 22, 2026

Version 1.1
Update in post #1

add Dark / Light mode

A KVS maintains the selected state

Click on the icon below right to change mode.

PaulMeuris · Feb 22, 2026

cool!

P.S. the java code was not corrected.

Grinaute · Feb 23, 2026

Hi Paul,
I replaced it with:

B4X: Copy

public void caller(String s){
    try{
        getBA().raiseEventFromUI(this, ‘webscroll’, s);
    } catch (Exception e) {
    }
}

and no more problems in Release mode (obfuscated). If that helps...

zed · Feb 23, 2026

Version1.3
update in post #1

ADD Mapping CTRL+

Fonction Markdown	Shortcut CTRL	Logic
Title (H1–H6)	CTRL + 1,,,6	H = Heading
Bold	CTRL + B	Standard
Italic	CTRL + I	Standard
CrossedOut	CTRL + D	D = Delete visual

Code block	CTRL + G	G = Gros code (block)
Citation (>)	CTRL + Q	Q = Quote
Simple list (•)	CTRL + L	L = List
Numbered list (1.)	CTRL + N	N = Numbered
Link	CTRL + K	Standard
Image	CTRL + M	M = Media
TaskEmpty [- ]	CTRL + T	T = Task
TaskDone [x]	CTRL + F	F = Finish
Horizontal line (---)	CTRL + R	R = Rule (ligne)

Java bug fix - Tank’s Grinaute

Why null instead of this?

Because raiseEventFromUI(this, …) assumes that "this" is a valid B4J module. But in this case, "this" refers to the Java class, not the B4J module.
So for some users, it works by chance, and for others, it crashes because B4J can't find the correct instance.
By setting null, B4J automatically searches for the correct module containing the webscroll sub.
If I'm wrong, please tell me

Toley · Feb 23, 2026

@zed Post #1 do not seems to have the files anymore.

zed · Feb 23, 2026

Toley said:
@zed Post #1 do not seems to have the files anymore.

Update. Sorry

T201016 · Mar 23, 2026

zed said:
MarkCraft - Markdown Editor

Version 1.0

A modern, fast, and intuitive Markdown editor, developed in B4J.
It combines a user-friendly text editor with a real-time HTML preview.

Main Features

Full Markdown Editor

Formatting: bold, italic, strikethrough

Headings H1 to H6

Bulleted and Numbered Lists

Quotations

Tasks: - [ ] and - [x]

Horizontal Lines

Code Insertion (```)

Content Insertion

Adding Links via a Dialog Box

Adding Images with ALT + URL

Auto-fill based on selection

Undo/Redo

Custom Undo/Redo System

History reset after each action

Dedicated buttons with Font Awesome icons

Preview

Real-time HTML preview

Integrated WebView

Instant Markdown rendering

Two-way scroll synchronization

Java ↔ JavaScript communication

File management

Open a .md file

Save as…

Copy all Markdown to clipboard

Automatic saving

Modern interface

Font Awesome icons

Compact toolbar

Adjustable SplitPane

Technologies used

B4J (RAD framework)

JavaFX (UI + WebView)

Font Awesome (icons)

JavaScript for Markdown rendering

HTML/CSS for the Preview

How it Works

The user types Markdown in the TextArea.

The text is sent to the WebView via JavaScript.

The HTML is rendered instantly.

Toolbar actions modify the text and update the preview.

Undo/Redo allows for easy reverting.

View attachment 170042

Have fun !

I seem to have gotten an unexpected error in the code:

Dim js As String = $"showMarkdownFromJava('${cssEscaped}', '${mdEscaped}')"$
engine.RunMethod("executeScript", Array(js))

Waiting for debugger to connect...
Program started.
*** mainpage: B4XPage_Created
*** mainpage: B4XPage_Appear
*** mainpage: B4XPage_Resize [mainpage]
Error occurred on line: 1045 (B4XMainPage)
java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at anywheresoftware.b4j.object.JavaObject.RunMethod(JavaObject.java:152)
at b4j.example.b4xmainpage._updatewebview(b4xmainpage.java:876)
at b4j.example.b4xmainpage._applytheme(b4xmainpage.java:658)
at b4j.example.b4xmainpage$ResumableSub_wv_PageFinished.resume(b4xmainpage.java:3095)
at anywheresoftware.b4a.shell.DebugResumableSub$DelegatableResumableSub.resumeAsUserSub(DebugResumableSub.java:47)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at anywheresoftware.b4a.shell.Shell.runMethod(Shell.java:632)
at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:234)
at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:167)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at anywheresoftware.b4a.BA.raiseEvent2(BA.java:117)
at anywheresoftware.b4a.shell.ShellBA.raiseEvent2(ShellBA.java:100)
at anywheresoftware.b4a.BA.raiseEvent(BA.java:104)
at anywheresoftware.b4a.shell.DebugResumableSub$DelegatableResumableSub.resume(DebugResumableSub.java:42)
at anywheresoftware.b4a.keywords.Common$2$1.run(Common.java:1106)
at com.sun.javafx.application.PlatformImpl.lambda$null$5(PlatformImpl.java:295)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.application.PlatformImpl.lambda$runLater$6(PlatformImpl.java:294)
at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$4(WinApplication.java:185)
at java.lang.Thread.run(Thread.java:750)
Caused by: netscape.javascript.JSException: ReferenceError: Can't find variable: marked
at com.sun.webkit.dom.JSObject.fwkMakeException(JSObject.java:156)
at com.sun.webkit.WebPage.twkExecuteScript(Native Method)
at com.sun.webkit.WebPage.executeScript(WebPage.java:1543)
at javafx.scene.web.WebEngine.executeScript(WebEngine.java:1007)
... 32 more

zed · Mar 23, 2026

ReferenceError: Can't find variable: marked
This means that the WebView is unable to load the CDN.

The WebView might be blocked by a corporate firewall, a proxy server, a network policy, or it might silently fail to load an external script.
Open this in your browser: https://cdn.jsdelivr.net/npm/marked/marked.min.js
If it doesn't open, that's exactly the problem.

You can download marked.min.js and place it in DirAssets to load it locally.

T201016 · Mar 24, 2026

zed said:
Open this in your browser: https://cdn.jsdelivr.net/npm/marked/marked.min.js
If it doesn't open, that's exactly the problem.

Hi, @zed
Yes, that's right. I opened the link in the browser and the text content of this script was displayed, i.e. the firewall passed the script, considering it harmless...

chjk · Jul 13, 2026

T201016 said:
Hi, @zed
Yes, that's right. I opened the link in the browser and the text content of this script was displayed, i.e. the firewall passed the script, considering it harmless...

Please upgrade b4j and Java to version 19！

T201016 · Jul 13, 2026

chjk said:
Please upgrade b4j and Java to version 19！

java update is enough.

Share My Creation MarkCraft - Markdown Editor

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