WebView cannot find objects opened via addJavascriptinterface in Lollipop
I've struggled with this for too long. Hope someone can help me. Here is my situation:
In our Android app, we are sending XMLHttpRequests from our WebView via Java / Android so that we can add an OAuth2 token and track requests. This worked great until Android 5 was released.
Since Android 5, whenever a WebView tries to interact with an open object in JavaScript, the following exception is thrown:
java.lang.ClassNotFoundException: Didn't find class "com/company/android/AndroidXMLHttpRequest$AjaxRequest" on path: DexPathList[[zip file "/system/app/webview/webview.apk"],nativeLibraryDirectories=[/system/app/webview/lib/x86_64, /vendor/lib64, /system/lib64]]
at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
at java.lang.ClassLoader.loadClass(ClassLoader.java:469)
at com.android.org.chromium.base.SystemMessageHandler.nativeDoRunLoopOnce(Native Method)
at com.android.org.chromium.base.SystemMessageHandler.handleMessage(SystemMessageHandler.java:53)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.os.HandlerThread.run(HandlerThread.java:61)
Suppressed: java.lang.ClassNotFoundException: Invalid name: com/company/android/AndroidXMLHttpRequest$AjaxRequest
at java.lang.Class.classForName(Native Method)
at java.lang.BootClassLoader.findClass(ClassLoader.java:781)
at java.lang.BootClassLoader.loadClass(ClassLoader.java:841)
at java.lang.ClassLoader.loadClass(ClassLoader.java:504)
... 6 more
Results for different configurations:
- This code works fine on physical and virtual devices running Android <5.
- This code breaks down on physical devices running Android 5 and 5.1
- This code works fine on a virtual device running Android 5.0
- This code breaks down to virtual devices running Android 5.1
- There is no difference between running debug or production build
Some information about the code: * WebViewFragment runs in MainActivity.onCreate
. * WebViewFragment.onCreateView
creates an object that will be displayed in the WebView * JavaScript interface added to WebViewClient.onPageFinished
* The class that is exposed is Public * All methods of the public class are public and annotated@JavascriptInterface
Launching Lollipop, WebView has been disconnected from Android, so it can be updated via the Play Store. This also indicates an error:
DexPathList[[zip file "/system/app/webview/webview.apk"],nativeLibraryDirectories=[/system/app/webview/lib/x86_64, /vendor/lib64, /system/lib64]]
I have looked through the release notes to see if we need to do something about the WebView and addJavaScriptInterface, but I cannot find anything.
Anyone have any ideas what might be causing it to fail?
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Sorry for that, there was an error in the WebView: http://crbug.com/491800
The bug appeared in Android 5.1, so the original 5.0 works fine (emulator). But on physical Lollipop devices with the Play Store, the WebView is updated to a more recent version (43) which was still broken. The fix worked with WebView version 44, which I think is rolling out now.
However, there is a workaround. In the injected method, which takes an instance AjaxRequest
, you need to replace the argument type with Object
and then convert to AjaxRequest
later in a function (see this comment for an example). This way, the WebView will stop trying to find a class that it cannot access at this point.
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