Summary: Nested Classes | Constants | Methods | Inherited Methods

WebViewAssetLoader

Kotlin |Java

public final class WebViewAssetLoader
extends Object

java.lang.Object
↳	androidx.webkit.WebViewAssetLoader

Helper class to load local files including application's static assets and resources using http(s):// URLs inside a WebView class. Loading local files using web-like URLs instead of "file://" is desirable as it is compatible with the Same-Origin policy.

For more context about application's assets and resources and how to normally access them please refer to Android Developer Docs: App resources overview.

This class is expected to be used within WebViewClient.shouldInterceptRequest(WebView, WebResourceRequest), which is invoked on a different thread than application's main thread. Although instances are themselves thread-safe (and may be safely constructed on the application's main thread), exercise caution when accessing private data or the view system.

Using http(s):// URLs to access local resources may conflict with a real website. This means that local files should only be hosted on domains your organization owns (at paths reserved for this purpose) or the default domain reserved for this: appassets.androidplatform.net.

A typical usage would be like:

     final WebViewAssetLoader assetLoader = new WebViewAssetLoader.Builder()
              .addPathHandler("/assets/", new AssetsPathHandler(this))
              .addPathHandler("/res/", new ResourcesPathHandler(this))
              .build();

     webView.setWebViewClient(new WebViewClient() {
         @Override
         public WebResourceResponse shouldInterceptRequest(WebView view,
                                          WebResourceRequest request) {
             return assetLoader.shouldInterceptRequest(request.getUrl());
         }
     });
     // Assets are hosted under http(s)://appassets.androidplatform.net/assets/... .
     // If the application's assets are in the "main/assets" folder this will read the file
     // from "main/assets/www/index.html" and load it as if it were hosted on:
     // https://appassets.androidplatform.net/assets/www/index.html
     webview.loadUrl("https://appassets.androidplatform.net/assets/www/index.html");

Summary

Nested classes
`class`	`WebViewAssetLoader.AssetsPathHandler` Handler class to open a file from assets directory in the application APK.
`class`	`WebViewAssetLoader.Builder` A builder class for constructing `WebViewAssetLoader` objects.
`interface`	`WebViewAssetLoader.PathHandler` A handler that produces responses for a registered path.
`class`	`WebViewAssetLoader.ResourcesPathHandler` Handler class to open a file from resources directory in the application APK.

Constants
`String`	`DEFAULT_DOMAIN` An unused domain reserved for Android applications to intercept requests for app assets.

Public methods
`WebResourceResponse`	`shouldInterceptRequest(Uri url)` Attempt to resolve the `url` to an application resource or asset, and return a `WebResourceResponse` for the content.

Inherited methods

From class


        
          java.lang.Object

`Object`	`clone()`
`boolean`	`equals(Object arg0)`
`void`	`finalize()`
`final Class<?>`	`getClass()`
`int`	`hashCode()`
`final void`	`notify()`
`final void`	`notifyAll()`
`String`	`toString()`
`final void`	`wait(long arg0, int arg1)`
`final void`	`wait(long arg0)`
`final void`	`wait()`

Constants

DEFAULT_DOMAIN

public static final String DEFAULT_DOMAIN

An unused domain reserved for Android applications to intercept requests for app assets.

It is used by default unless the user specified a different domain.

Constant Value: "appassets.androidplatform.net"

Public methods

shouldInterceptRequest

public WebResourceResponse shouldInterceptRequest (Uri url)

Attempt to resolve the url to an application resource or asset, and return a WebResourceResponse for the content.

This method should be invoked from within WebViewClient.shouldInterceptRequest(android.webkit.WebView, String).

Parameters
`url`	`Uri`: the URL to process.

Returns
`WebResourceResponse`	`WebResourceResponse` if the request URL matches a registered URL, `null` otherwise.

WebViewAssetLoader

Summary

Nested classes

Constants

Public methods

Inherited methods

Constants

DEFAULT_DOMAIN

Public methods

shouldInterceptRequest

Interfaces

Classes