ART 在加载完成之前杀死 WebView答案

【问题标题】：ART kills WebView before loading finishedART 在加载完成之前杀死 WebView
【发布时间】：2016-07-15 17:37:38
【问题描述】：

我正在尝试从使用 JavaScript 的网站中检索 html。我的方法如下：

创建一个无头 WebView（没有在 XML 中定义任何视图）并启用 JS。
使用加载完成时调用的方法创建一个 JavaScriptInterface。
覆盖我提供的 WebClientView 的 onPageFinished 方法。这里的代码注入 JavaScript 来调用我在 JavaScriptInterface 中定义的方法，将页面的 html 内容作为参数传递。

有趣的是，这段代码有效，但不一致。一次它会按预期工作，下一次什么都不会发生。我收到了各种奇怪的 logcat 消息，其中一个我怀疑可能是一个坏信号：W/art: Attempt to remove non-JNI local reference, dumping thread。今天突然想到一个想法：也许有时我的 WebView 会因为运行时环境进行优化而被杀死（而我的 WebView 没有链接到它的 XML View 对象）？

因此，我决定尝试在我的 XML 中创建一个 WebView 并使用相同的代码，而不是仅仅在代码中创建一个。现在，每次我运行代码时，代码都能正常运行，并且我不再收到那些线程转储日志消息。一旦我看到页面加载完成，代码就会被执行。

请注意，我注意到我引用的这个特定网站需要相对较长的时间来加载（只要几秒钟），而且 onPageFinished 会被多次调用，除非它是最后一个，否则会使用未处理的 JS 传递 html打电话。

所以，我的问题是：在使用无头版本（或任何其他解决方法）时，有什么方法可以防止 ART 转储我的线程？我想保留在 XML 中定义的 WebView，并将其可见性设置为 false，但这似乎是一个资源密集型解决方案。

我正在使用 Android 模拟器（尽管我使用物理设备也得到了相同的结果），目标 API 是 24，最低 API 15。

相关代码：

private void fetchHTML(View view, String url) {
    class JSInterface{
        @JavascriptInterface
        public void processHTML(String html){
            Log.d(LOG_TAG, html); // This bit of code sometimes gets executed, and sometimes does not
        }
    }
    //final WebView webView = (WebView) view.findViewById(R.id.webview);
    final WebView webView = new WebView(context);
    WebSettings settings = webView.getSettings();
    settings.setDomStorageEnabled(true);
    webView.addJavascriptInterface(new JSInterface(), "Android");
    webView.setWebChromeClient(new WebChromeClient());
    webView.setWebViewClient(new WebViewClient(){
        @Override
        public void onPageFinished(WebView view, String url) {
            super.onPageFinished(view, url);
            if(webView.getProgress() == 100){
                webView.loadUrl("javascript:window.Android.processHTML("
                        + "'<head>'+document.getElementsByTagName('html')[0].innerHTML+'</head>');");
            }
        }
    });

    settings.setJavaScriptEnabled(true);
    webView.loadUrl(url);
}

未正确执行时的相关logcat：

07-15 17:16:27.616 17779-17779/com.michaelsvit.kolnoa W/System: ClassLoader referenced unknown path: /data/app/com.michaelsvit.kolnoa-2/lib/x86
07-15 17:16:28.214 17779-17779/com.michaelsvit.kolnoa W/System: ClassLoader referenced unknown path: /data/app/com.michaelsvit.kolnoa-2/lib/x86
07-15 17:16:28.267 17779-17779/com.michaelsvit.kolnoa W/art: Before Android 4.1, method android.graphics.PorterDuffColorFilter android.support.graphics.drawable.VectorDrawableCompat.updateTintFilter(android.graphics.PorterDuffColorFilter, android.content.res.ColorStateList, android.graphics.PorterDuff$Mode) would have incorrectly overridden the package-private method in android.graphics.drawable.Drawable
07-15 17:16:28.448 17779-17779/com.michaelsvit.kolnoa I/WebViewFactory: Loading com.android.webview version 44.0.2403.119 (code 246011910)
07-15 17:16:28.456 17779-17779/com.michaelsvit.kolnoa W/System: ClassLoader referenced unknown path: /system/app/webview/lib/x86
07-15 17:16:28.465 17779-17779/com.michaelsvit.kolnoa I/LibraryLoader: Time to load native libraries: 3 ms (timestamps 8656-8659)
07-15 17:16:28.465 17779-17779/com.michaelsvit.kolnoa I/LibraryLoader: Expected native library version number "",actual native library version number ""
07-15 17:16:28.470 17779-17779/com.michaelsvit.kolnoa V/WebViewChromiumFactoryProvider: Binding Chromium to main looper Looper (main, tid 1) {c4bffce}
07-15 17:16:28.470 17779-17779/com.michaelsvit.kolnoa I/LibraryLoader: Expected native library version number "",actual native library version number ""
07-15 17:16:28.470 17779-17779/com.michaelsvit.kolnoa I/chromium: [INFO:library_loader_hooks.cc(120)] Chromium logging enabled: level = 0, default verbosity = 0
07-15 17:16:28.476 17779-17779/com.michaelsvit.kolnoa I/BrowserStartupController: Initializing chromium process, singleProcess=true
07-15 17:16:28.479 17779-17779/com.michaelsvit.kolnoa W/art: Attempt to remove non-JNI local reference, dumping thread
07-15 17:16:28.479 17779-17779/com.michaelsvit.kolnoa E/SysUtils: ApplicationContext is null in ApplicationStatus
07-15 17:16:28.484 17779-17779/com.michaelsvit.kolnoa W/chromium: [WARNING:resource_bundle.cc(285)] locale_file_path.empty()
07-15 17:16:28.487 17779-17779/com.michaelsvit.kolnoa E/libEGL: validate_display:255 error 3008 (EGL_BAD_DISPLAY)
07-15 17:16:28.487 17779-17779/com.michaelsvit.kolnoa E/libEGL: validate_display:255 error 3008 (EGL_BAD_DISPLAY)

                                                                [ 07-15 17:16:28.488 17779:17779 D/         ]
                                                                HostConnection::get() New Host Connection established 0xac3edff0, tid 17779
07-15 17:16:28.525 17779-17779/com.michaelsvit.kolnoa E/eglCodecCommon: glUtilsParamSize: unknow param 0x00008d57
07-15 17:16:28.552 17779-17779/com.michaelsvit.kolnoa E/DataReductionProxySettingListener: No DRP key due to exception:java.lang.ClassNotFoundException: com.android.webview.chromium.Drp
07-15 17:16:28.568 17779-17831/com.michaelsvit.kolnoa W/AudioManagerAndroid: Requires BLUETOOTH permission
07-15 17:16:28.578 17779-17779/com.michaelsvit.kolnoa W/art: Attempt to remove non-JNI local reference, dumping thread
07-15 17:16:28.582 17779-17779/com.michaelsvit.kolnoa W/AwContents: onDetachedFromWindow called when already detached. Ignoring
07-15 17:16:28.584 17779-17779/com.michaelsvit.kolnoa W/art: Attempt to remove non-JNI local reference, dumping thread
07-15 17:16:28.585 17779-17779/com.michaelsvit.kolnoa W/AwContents: onDetachedFromWindow called when already detached. Ignoring
07-15 17:16:28.587 17779-17779/com.michaelsvit.kolnoa W/art: Attempt to remove non-JNI local reference, dumping thread
07-15 17:16:28.587 17779-17779/com.michaelsvit.kolnoa W/art: Attempt to remove non-JNI local reference, dumping thread
07-15 17:16:28.620 17779-17841/com.michaelsvit.kolnoa D/OpenGLRenderer: Use EGL_SWAP_BEHAVIOR_PRESERVED: true
07-15 17:16:28.639 17779-17829/com.michaelsvit.kolnoa W/chromium: [WARNING:data_reduction_proxy_config.cc(423)] SPDY proxy OFF at startup
07-15 17:16:28.740 17779-17841/com.michaelsvit.kolnoa I/OpenGLRenderer: Initialized EGL, version 1.4

                                                                        [ 07-15 17:16:28.741 17779:17841 D/         ]
                                                                        HostConnection::get() New Host Connection established 0xa0a5f8d0, tid 17841
07-15 17:16:28.782 17779-17841/com.michaelsvit.kolnoa W/EGL_emulation: eglSurfaceAttrib not implemented
07-15 17:16:28.782 17779-17841/com.michaelsvit.kolnoa W/OpenGLRenderer: Failed to set EGL_SWAP_BEHAVIOR on surface 0xaa3d9180, error=EGL_SUCCESS

                                                                        [ 07-15 17:16:28.815 17779:17850 D/         ]
                                                                        HostConnection::get() New Host Connection established 0xa0c82c80, tid 17850
07-15 17:16:29.166 17779-17779/com.michaelsvit.kolnoa W/BindingManager: Cannot call determinedVisibility() - never saw a connection for the pid: 17779
07-15 17:16:29.279 17779-17779/com.michaelsvit.kolnoa D/MovieGridFragment: 
07-15 17:16:29.768 17779-17779/com.michaelsvit.kolnoa W/BindingManager: Cannot call determinedVisibility() - never saw a connection for the pid: 17779
07-15 17:16:30.894 17779-17779/com.michaelsvit.kolnoa I/chromium: [INFO:CONSOLE(2)] "Uncaught TypeError: Cannot read property 'length' of undefined", source:  (2)
07-15 17:16:31.196 17779-17829/com.michaelsvit.kolnoa W/chromium: [WARNING:spdy_session.cc(2527)] Received WINDOW_UPDATE for invalid stream 1

【问题讨论】：

标签： java android webview

【解决方案1】：

按照我提出的想法，我保留了 XML 定义的 WebView（可见性设置为“已消失”）并使用它而不是在运行时创建它。从那以后我没有遇到任何问题。

【讨论】：