WebViewCompat

@UiThread
@RequiresFeature(name = WebViewFeature.DOCUMENT_START_SCRIPT, enforcement = "androidx.webkit.WebViewFeature#isFeatureSupported")
java-static fun addDocumentStartJavaScript(
    webview: WebView,
    script: String,
    allowedOriginRules: (Mutable)Set<String!>
): ScriptHandler

Adds a JavaScript script to the WebView which will be executed in any frame whose origin matches allowedOriginRules when the document begins to load.

Note that the script will run before any of the page's JavaScript code and the DOM tree might not be ready at this moment. It will block the loading of the page until it's finished, so should be kept as short as possible.

The injected object from addWebMessageListener API will be injected first and the script can rely on the injected object to send messages to the app.

The script will only run in frames which begin loading after the call returns, therefore it should typically be called before making any loadUrl(), loadData() or loadDataWithBaseURL() call to load the page.

This method can be called multiple times to inject multiple scripts. If more than one script matches a frame's origin, they will be executed in the order they were added.

See addWebMessageListener for the rules of the allowedOriginRules parameter.

This method should only be called if isFeatureSupported returns true for DOCUMENT_START_SCRIPT.

@UiThread
@RequiresFeature(name = WebViewFeature.WEB_MESSAGE_LISTENER, enforcement = "androidx.webkit.WebViewFeature#isFeatureSupported")
java-static fun addWebMessageListener(
    webView: WebView,
    jsObjectName: String,
    allowedOriginRules: (Mutable)Set<String!>,
    listener: WebViewCompat.WebMessageListener
): Unit

Adds a WebMessageListener to the WebView and injects a JavaScript object into each frame that the WebMessageListener will listen on.

The injected JavaScript object will be named jsObjectName in the global scope. This will inject the JavaScript object in any frame whose origin matches allowedOriginRules for every navigation after this call, and the JavaScript object will be available immediately when the page begins to load.

Each allowedOriginRules entry must follow the format SCHEME "://" [ HOSTNAME_PATTERN [ ":" PORT ] ], each part is explained in the below table:

Note that this is a powerful API, as the JavaScript object will be injected when the frame's origin matches any one of the allowed origins. The HTTPS scheme is strongly recommended for security; allowing HTTP origins exposes the injected object to any potential network-based attackers. If a wildcard "*" is provided, it will inject the JavaScript object to all frames. A wildcard should only be used if the app wants any third party web page to be able to use the injected object. When using a wildcard, the app must treat received messages as untrustworthy and validate any data carefully.

This method can be called multiple times to inject multiple JavaScript objects.

Let's say the injected JavaScript object is named myObject. We will have following methods on that object once it is available to use:

// 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)

        

We start the communication between JavaScript and the app from the JavaScript side. In order to send message from the app to JavaScript, it needs to post a message from JavaScript first, so the app will have a JavaScriptReplyProxy object to respond. Example:

// 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);
}

Suppose the communication is already setup, to send ArrayBuffer from the app to web, it needs to check feature flag(WEB_MESSAGE_ARRAY_BUFFER). Here is a example to send file content from app to web:

// 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!");

Suppose the communication is already setup, and feature flag WEB_MESSAGE_ARRAY_BUFFER is check. Here is a example to download image in WebView, and send to app:

// 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.
    }
  }
};

This method should only be called if isFeatureSupported returns true for WEB_MESSAGE_LISTENER.

@UiThread
@RequiresFeature(name = WebViewFeature.CREATE_WEB_MESSAGE_CHANNEL, enforcement = "androidx.webkit.WebViewFeature#isFeatureSupported")
java-static fun createWebMessageChannel(webview: WebView): Array<WebMessagePortCompat!>

Creates a message channel to communicate with JS and returns the message ports that represent the endpoints of this message channel. The HTML5 message channel functionality is described here

The returned message channels are entangled and already in started state.

This method should only be called if isFeatureSupported returns true for CREATE_WEB_MESSAGE_CHANNEL.

@AnyThread
java-static fun getCurrentWebViewPackage(context: Context): PackageInfo?

If WebView has already been loaded into the current process this method will return the package that was used to load it. Otherwise, the package that would be used if the WebView was loaded right now will be returned; this does not cause WebView to be loaded, so this information may become outdated at any time. The WebView package changes either when the current WebView package is updated, disabled, or uninstalled. It can also be changed through a Developer Setting. If the WebView package changes, any app process that has loaded WebView will be killed. The next time the app starts and loads WebView it will use the new WebView package instead.

@UiThread
@RequiresFeature(name = WebViewFeature.MULTI_PROFILE, enforcement = "androidx.webkit.WebViewFeature#isFeatureSupported")
java-static fun getProfile(webView: WebView): Profile

Gets the Profile associated with this WebView.

Gets the profile object set on this WebView using setProfile, or the default profile if it has not been changed.

@AnyThread
@RequiresFeature(name = WebViewFeature.SAFE_BROWSING_PRIVACY_POLICY_URL, enforcement = "androidx.webkit.WebViewFeature#isFeatureSupported")
java-static fun getSafeBrowsingPrivacyPolicyUrl(): Uri

Returns a URL pointing to the privacy policy for Safe Browsing reporting.

This method should only be called if isFeatureSupported returns true for SAFE_BROWSING_PRIVACY_POLICY_URL.

@AnyThread
@RequiresFeature(name = WebViewFeature.GET_VARIATIONS_HEADER, enforcement = "androidx.webkit.WebViewFeature#isFeatureSupported")
java-static fun getVariationsHeader(): String

Gets the WebView variations encoded to be used as the X-Client-Data HTTP header.

The app is responsible for adding the X-Client-Data header to any request that may use variations metadata, such as requests to Google web properties. The returned string will be a base64 encoded ClientVariations proto: https://source.chromium.org/chromium/chromium/src/+/main:components/variations/proto/client_variations.proto

@UiThread
@RequiresFeature(name = WebViewFeature.GET_WEB_CHROME_CLIENT, enforcement = "androidx.webkit.WebViewFeature#isFeatureSupported")
java-static fun getWebChromeClient(webview: WebView): WebChromeClient?

Gets the WebChromeClient.

This method should only be called if isFeatureSupported returns true for GET_WEB_CHROME_CLIENT.

@UiThread
@RequiresFeature(name = WebViewFeature.GET_WEB_VIEW_CLIENT, enforcement = "androidx.webkit.WebViewFeature#isFeatureSupported")
java-static fun getWebViewClient(webview: WebView): WebViewClient

Gets the WebViewClient for the WebView argument.

This method should only be called if isFeatureSupported returns true for GET_WEB_VIEW_CLIENT.

@UiThread
@RequiresFeature(name = WebViewFeature.GET_WEB_VIEW_RENDERER, enforcement = "androidx.webkit.WebViewFeature#isFeatureSupported")
java-static fun getWebViewRenderProcess(webview: WebView): WebViewRenderProcess?

Gets the WebView renderer associated with this WebView.

In Android O and above, WebView may run in "multiprocess" mode. In multiprocess mode, rendering of web content is performed by a sandboxed renderer process separate to the application process. This renderer process may be shared with other WebViews in the application, but is not shared with other application processes.

If WebView is running in multiprocess mode, this method returns a handle to the renderer process associated with the WebView, which can be used to control the renderer process.

This method should only be called if isFeatureSupported returns true for GET_WEB_VIEW_RENDERER.

@UiThread
@RequiresFeature(name = WebViewFeature.WEB_VIEW_RENDERER_CLIENT_BASIC_USAGE, enforcement = "androidx.webkit.WebViewFeature#isFeatureSupported")
java-static fun getWebViewRenderProcessClient(webview: WebView): WebViewRenderProcessClient?

Gets the renderer client object associated with this WebView.

This method should only be called if isFeatureSupported returns true for WEB_VIEW_RENDERER_CLIENT_BASIC_USAGE.

@UiThread
@RequiresFeature(name = WebViewFeature.MUTE_AUDIO, enforcement = "androidx.webkit.WebViewFeature#isFeatureSupported")
java-static fun isAudioMuted(webView: WebView): Boolean

Returns whether this WebView is muted.

@AnyThread
@RequiresFeature(name = WebViewFeature.MULTI_PROCESS, enforcement = "androidx.webkit.WebViewFeature#isFeatureSupported")
java-static fun isMultiProcessEnabled(): Boolean

Returns true if WebView is running in multi process mode.

In Android O and above, WebView may run in "multiprocess" mode. In multiprocess mode, rendering of web content is performed by a sandboxed renderer process separate to the application process. This renderer process may be shared with other WebViews in the application, but is not shared with other application processes.

@UiThread
@RequiresFeature(name = WebViewFeature.VISUAL_STATE_CALLBACK, enforcement = "androidx.webkit.WebViewFeature#isFeatureSupported")
java-static fun postVisualStateCallback(
    webview: WebView,
    requestId: Long,
    callback: WebViewCompat.VisualStateCallback
): Unit

Posts a VisualStateCallback, which will be called when the current state of the WebView is ready to be drawn.

Because updates to the DOM are processed asynchronously, updates to the DOM may not immediately be reflected visually by subsequent onDraw invocations. The VisualStateCallback provides a mechanism to notify the caller when the contents of the DOM at the current time are ready to be drawn the next time the WebView draws.

The next draw after the callback completes is guaranteed to reflect all the updates to the DOM up to the point at which the VisualStateCallback was posted, but it may also contain updates applied after the callback was posted.

The state of the DOM covered by this API includes the following:

• primitive HTML elements (div, img, span, etc..)
• images
• CSS animations
• WebGL
• canvas

• the video tag

To guarantee that the WebView will successfully render the first frame after the onComplete method has been called a set of conditions must be met:

• If the WebView's visibility is set to VISIBLE then * the WebView must be attached to the view hierarchy.
• If the WebView's visibility is set to INVISIBLE then the WebView must be attached to the view hierarchy and must be made VISIBLE from the onComplete method.
• If the WebView's visibility is set to GONE then the WebView must be attached to the view hierarchy and its LayoutParams's width and height need to be set to fixed values and must be made VISIBLE from the onComplete method.

When using this API it is also recommended to enable pre-rasterization if the is off screen to avoid flickering. See setOffscreenPreRaster for more details and do consider its caveats.

This method should only be called if isFeatureSupported returns true for VISUAL_STATE_CALLBACK.

@UiThread
@RequiresFeature(name = WebViewFeature.POST_WEB_MESSAGE, enforcement = "androidx.webkit.WebViewFeature#isFeatureSupported")
java-static fun postWebMessage(
    webview: WebView,
    message: WebMessageCompat,
    targetOrigin: Uri
): Unit

Post a message to main frame. The embedded application can restrict the messages to a certain target origin. See HTML5 spec for how target origin can be used.

A target origin can be set as a wildcard ("*"). However this is not recommended. See the page above for security issues.

This method should only be called if isFeatureSupported returns true for POST_WEB_MESSAGE.

When posting a WebMessageCompat with type TYPE_ARRAY_BUFFER, this method should check if isFeatureSupported returns true for WEB_MESSAGE_ARRAY_BUFFER. Example:

if (message.getType() == WebMessageCompat.TYPE_ARRAY_BUFFER) {
    if (WebViewFeature.isFeatureSupported(WebViewFeature.WEB_MESSAGE_ARRAY_BUFFER) {
        // ArrayBuffer message is supported, send message here.
        WebViewCompat.postWebMessage(webview, message, ...);
    }
}

@UiThread
@RequiresFeature(name = WebViewFeature.WEB_MESSAGE_LISTENER, enforcement = "androidx.webkit.WebViewFeature#isFeatureSupported")
java-static fun removeWebMessageListener(webview: WebView, jsObjectName: String): Unit

Removes the WebMessageListener associated with jsObjectName.

Note that after this call, the injected JavaScript object is still in the JavaScript context, however any message sent after this call won't reach the WebMessageListener.

This method should only be called if isFeatureSupported returns true for WEB_MESSAGE_LISTENER.

@UiThread
@RequiresFeature(name = WebViewFeature.MUTE_AUDIO, enforcement = "androidx.webkit.WebViewFeature#isFeatureSupported")
java-static fun setAudioMuted(webView: WebView, mute: Boolean): Unit

Mute or un-mute this WebView.

@AnyThread
@RequiresFeature(name = WebViewFeature.DEFAULT_TRAFFICSTATS_TAGGING, enforcement = "androidx.webkit.WebViewFeature#isFeatureSupported")
java-static fun setDefaultTrafficStatsTag(tag: Int): Unit

Sets the default android.net.TrafficStats tag to use when accounting socket traffic caused by WebView. If set, this tag is global for all requests sent by the WebView library within your app.

If no tag is set (e.g. this method isn't called), then Android accounts for the socket traffic caused by WebView as if the tag value were set to 0. See setThreadStatsTag for more information.

NOTE: Setting a tag disallows sharing of sockets with requests with other tags, which may adversely affect performance by prohibiting connection sharing. In other words, use of multiplexed sockets (e.g. HTTP/2 and QUIC) will only be allowed if all requests have the same socket tag. To minimize impact, you should not change the value of this tag often.

@UiThread
@RequiresFeature(name = WebViewFeature.MULTI_PROFILE, enforcement = "androidx.webkit.WebViewFeature#isFeatureSupported")
java-static fun setProfile(webView: WebView, profileName: String): Unit

Sets the Profile with its name as the current Profile for this WebView.

• This should be called before doing anything else with WebView other than attaching it to the view hierarchy.
• This should be only called if WebView is to use a Profile other than the default.
• This method will create the profile if it doesn't exist.

@AnyThread
@RequiresFeature(name = WebViewFeature.SAFE_BROWSING_ALLOWLIST, enforcement = "androidx.webkit.WebViewFeature#isFeatureSupported")
java-static fun setSafeBrowsingAllowlist(
    hosts: (Mutable)Set<String!>,
    callback: ValueCallback<Boolean!>?
): Unit

Configures a set of hosts (domain names/IP addresses) that are exempt from SafeBrowsing checks. The set is global for all the WebViews.

Each rule should take one of these:

All other rules, including wildcards, are invalid.

The correct syntax for hosts is defined by RFC 3986.

This method should only be called if isFeatureSupported returns true for SAFE_BROWSING_ALLOWLIST.

@AnyThread
@RequiresFeature(name = WebViewFeature.SAFE_BROWSING_WHITELIST, enforcement = "androidx.webkit.WebViewFeature#isFeatureSupported")
java-static fun setSafeBrowsingWhitelist(
    hosts: (Mutable)List<String!>,
    callback: ValueCallback<Boolean!>?
): Unit

Sets the list of hosts (domain names/IP addresses) that are exempt from SafeBrowsing checks. The list is global for all the WebViews.

Each rule should take one of these:

All other rules, including wildcards, are invalid.

The correct syntax for hosts is defined by RFC 3986.

This method should only be called if isFeatureSupported returns true for SAFE_BROWSING_WHITELIST.

@UiThread
@RequiresFeature(name = WebViewFeature.WEB_VIEW_RENDERER_CLIENT_BASIC_USAGE, enforcement = "androidx.webkit.WebViewFeature#isFeatureSupported")
java-static fun setWebViewRenderProcessClient(
    webview: WebView,
    webViewRenderProcessClient: WebViewRenderProcessClient?
): Unit

Sets the renderer client object associated with this WebView.

See setWebViewRenderProcessClient for details, with the following differences:

Callbacks will execute directly on the thread on which this WebView was instantiated.

Passing null for webViewRenderProcessClient will clear the renderer client object for this WebView.

This method should only be called if isFeatureSupported returns true for WEB_VIEW_RENDERER_CLIENT_BASIC_USAGE.

@UiThread
@RequiresFeature(name = WebViewFeature.WEB_VIEW_RENDERER_CLIENT_BASIC_USAGE, enforcement = "androidx.webkit.WebViewFeature#isFeatureSupported")
java-static fun setWebViewRenderProcessClient(
    webview: WebView,
    executor: Executor,
    webViewRenderProcessClient: WebViewRenderProcessClient
): Unit

Sets the renderer client object associated with this WebView.

The renderer client encapsulates callbacks relevant to WebView renderer state. See WebViewRenderProcessClient for details.

Although many WebView instances may share a single underlying renderer, and renderers may live either in the application process, or in a sandboxed process that is isolated from the application process, instances of WebViewRenderProcessClient are set per-WebView. Callbacks represent renderer events from the perspective of this WebView, and may or may not be correlated with renderer events affecting other WebViews.

This method should only be called if isFeatureSupported returns true for WEB_VIEW_RENDERER_CLIENT_BASIC_USAGE.

@AnyThread
@RequiresFeature(name = WebViewFeature.START_SAFE_BROWSING, enforcement = "androidx.webkit.WebViewFeature#isFeatureSupported")
java-static fun startSafeBrowsing(context: Context, callback: ValueCallback<Boolean!>?): Unit

Starts Safe Browsing initialization.

URL loads are not guaranteed to be protected by Safe Browsing until after callback is invoked with true. Safe Browsing is not fully supported on all devices. For those devices callback will receive false.

This should not be called if Safe Browsing has been disabled by manifest tag or setSafeBrowsingEnabled. This prepares resources used for Safe Browsing.

This should be called with the Application Context (and will always use the Application context to do its work regardless).

This method should only be called if isFeatureSupported returns true for START_SAFE_BROWSING.

@WebViewCompat.ExperimentalAsyncStartUp
@AnyThread
java-static fun startUpWebView(
    config: WebViewStartUpConfig,
    callback: WebViewCompat.WebViewStartUpCallback
): Unit

Asynchronously trigger WebView startup.

WebView startup is a time-consuming process that is normally triggered during the first usage of WebView related APIs. WebView startup happens once per process. For example, the first call to new WebView() can take longer to complete than future calls due to WebView startup being triggered. The Android UI thread remains blocked till the startup completes.

This method allows callers to trigger WebView startup at a time of their choosing.

There are performance improvements this API provides. This method ensures that the portions of WebView startup which are able to run in the background will do so. Other portions of startup will still run on the UI thread.

Any APIs in android.webkit and androidx.webkit (including WebViewFeature) MUST only be called after the callback is invoked in order to ensure the maximum benefit. There is no feature check or call to WebViewFeature required for using this method.

This API can be called multiple times. The callback will be called promptly if startup has already completed.

This is an experimental API and unsuitable for non-experimental use. This method can be removed in future versions of the library.