WebViewCompat

@UiThread
@RequiresFeature(name = WebViewFeature.DOCUMENT_START_SCRIPT, enforcement = "androidx.webkit.WebViewFeature#isFeatureSupported")
public static @NonNull ScriptHandler addDocumentStartJavaScript(
    @NonNull WebView webview,
    @NonNull String script,
    @NonNull Set<String> allowedOriginRules
)

@UiThread
@RequiresFeature(name = WebViewFeature.WEB_MESSAGE_LISTENER, enforcement = "androidx.webkit.WebViewFeature#isFeatureSupported")
public static void addWebMessageListener(
    @NonNull WebView webView,
    @NonNull String jsObjectName,
    @NonNull Set<String> allowedOriginRules,
    @NonNull WebViewCompat.WebMessageListener listener
)

// Web page (in JavaScript)
// message needs to be a JavaScript String or ArrayBuffer, MessagePorts is an optional
// parameter.
myObject.postMessage(message[, MessagePorts])

          

// To receive messages posted from the app side, assign a function to the "onmessage"
// property. This function should accept a single "event" argument. "event" has a "data"
// property, which is the message String or ArrayBuffer from the app side.
myObject.onmessage = function(event) { ... }

          

// To be compatible with DOM EventTarget's addEventListener, it accepts type and listener
// parameters, where type can be only "message" type and listener can only be a JavaScript
// function for myObject. An event object will be passed to listener with a "data" property,
// which is the message String or ArrayBuffer from the app side.
myObject.addEventListener(type, listener)

          

// To be compatible with DOM EventTarget's removeEventListener, it accepts type and listener
// parameters, where type can be only "message" type and listener can only be a JavaScript
// function for myObject.
myObject.removeEventListener(type, listener)

        

// Web page (in JavaScript)
myObject.onmessage = function(event) {
  // prints "Got it!" when we receive the app's response.
  console.log(event.data);
}
myObject.postMessage("I'm ready!");

// App (in Java)
WebMessageListener myListener = new WebMessageListener() {
  @Override
  public void onPostMessage(WebView view, WebMessageCompat message, Uri sourceOrigin,
           boolean isMainFrame, JavaScriptReplyProxy replyProxy) {
    // do something about view, message, sourceOrigin and isMainFrame.
    replyProxy.postMessage("Got it!");
  }
};
if (WebViewFeature.isFeatureSupported(WebViewFeature.WEB_MESSAGE_LISTENER)) {
  WebViewCompat.addWebMessageListener(webView, "myObject", rules, myListener);
}

// App (in Java)
WebMessageListener myListener = new WebMessageListener() {
  @Override
  public void onPostMessage(WebView view, WebMessageCompat message, Uri sourceOrigin,
           boolean isMainFrame, JavaScriptReplyProxy replyProxy) {
    // Communication is setup, send file data to web.
    if (WebViewFeature.isFeatureSupported(WebViewFeature.WEB_MESSAGE_ARRAY_BUFFER)) {
      // Suppose readFileData method is to read content from file.
      byte[] fileData = readFileData("myFile.dat");
      replyProxy.postMessage(fileData);
    }
  }
}

// Web page (in JavaScript)
myObject.onmessage = function(event) {
  if (event.data instanceof ArrayBuffer) {
    const data = event.data;  // Received file content from app.
    const dataView = new DataView(data);
    // Consume file content by using JavaScript DataView to access ArrayBuffer.
  }
}
myObject.postMessage("Setup!");

// Web page (in JavaScript)
const response = await fetch('example.jpg');
if (response.ok) {
    const imageData = await response.arrayBuffer();
    myObject.postMessage(imageData);
}

// App (in Java)
WebMessageListener myListener = new WebMessageListener() {
  @Override
  public void onPostMessage(WebView view, WebMessageCompat message, Uri sourceOrigin,
           boolean isMainFrame, JavaScriptReplyProxy replyProxy) {
    if (message.getType() == WebMessageCompat.TYPE_ARRAY_BUFFER) {
      byte[] imageData = message.getArrayBuffer();
      // do something like draw image on ImageView.
    }
  }
};

@UiThread
@RequiresFeature(name = WebViewFeature.CREATE_WEB_MESSAGE_CHANNEL, enforcement = "androidx.webkit.WebViewFeature#isFeatureSupported")
public static @NonNull WebMessagePortCompat[] createWebMessageChannel(@NonNull WebView webview)

@AnyThread
public static @Nullable PackageInfo getCurrentWebViewPackage(@NonNull Context context)