Android Code Snippet [B4X] [B4A][B4J] [Snippet] AC_WebBridge - Native HTML/B4X communication

Imagine that you want to integrate an HTML page (WebView) with B4X or vice-versa. For example, creating a modern interface via HTML5/CSS and making it interact directly with your B4X logic...
Without using external libraries! One of the things I've learned in B4X is that external libs can be a lot of work, especially when the lib owner stops offering support or when Android updates break the library's internal reflection.
This snippet, AC_WebBridge, provides a lightweight, "Zero-Library" solution that uses native Java via JavaObject to create a stable bridge between both worlds.

Key Features:​

• Cross-Platform: Single class that handles both B4A and B4J logic.
• B4A Stability: It intercepts console.log messages using a native WebChromeClient. This is much more stable than standard reflection and avoids the common ContentSettingsAdapter error on newer Android versions.
• B4J Power: It uses the JSObject from the JavaFX engine to inject the B4X instance directly into the browser's window object.
• Clean Code: Strictly follows English naming conventions, AC_ prefixing, and SOLID principles.
• Bi-directional: Simple methods to send data from B4X to HTML and catch events from HTML in B4X.

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How it works:​

1. On the JavaScript side:
You use a universal function to detect if you are running on B4J (object injection) or B4A (console log):
JavaScript

function sendToB4X(message) {
if (window.b4x && window.b4x.NativeBridgeHandler) {
window.b4x.NativeBridgeHandler(message); // B4J path
} else {
console.log(message); // B4A path (captured by ChromeClient)
    }
}

2. On the B4X side:
You simply initialize the bridge and listen for the _OnJsMessage event:

' Initialize the bridge
Bridge.Initialize(Me, "MyBridge")
Bridge.Setup(WebView1)

' Send data to HTML
Bridge.RunJS(WebView1, "htmlFunction", Array("Hello from B4X"))

' Receive data from HTML
Public Sub MyBridge_OnJsMessage (Value As String)
    Log("Received from WebView: " & Value)
End Sub

Files attached:

• AC_WebBridge.bas: The standalone class.
• Example.zip: A full working project demonstrating the bi-directional flow

Support
If this library is useful to you and you'd like to support my work, feel free to buy me a coffee!

Click here to support via PayPal (yusrahassamo@gmail.com)