onRenderProcessGone（WebView 视图，RenderProcessGoneDetail 详细信息）示例

Question

下面我发布了我当前的onRenderProcessGone。

1. 在if (!detail.didCrash()) {} 中，实例变量“view”保证为空，重新初始化它是安全的。我应该自己重新初始化它还是系统会这样做？

2. 您能否指定应用程序如何继续执行的逻辑示例？如何更优雅地处理崩溃？

       @TargetApi(Build.VERSION_CODES.O)
       @Override
       public boolean onRenderProcessGone(WebView view, RenderProcessGoneDetail detail) {
           // WebViewClient.onRenderProcessGone was added in O.
           if (Build.VERSION.SDK_INT < Build.VERSION_CODES.O) {
               return false;
           }
           super.onRenderProcessGone(view, detail);
   
           if (!detail.didCrash()) {
               // Renderer was killed because the system ran out of memory.
               // The app can recover gracefully by creating a new WebView instance
               // in the foreground.
               Log.e("MY_APP", "System killed the WebView rendering process " +
                       "to reclaim memory. Recreating...");
   
               if (view != null) {
                   ((ViewGroup)view.getParent()).removeView(view);
                   view.destroy();
                   view = null;
               }
   
               // By this point, the instance variable "view" is guaranteed
               // to be null, so it's safe to reinitialize it.
   
               return true; // The app continues executing.
           }
   
           // Renderer crashed because of an internal error, such as a memory
           // access violation.
           Log.e("MY_APP", "The WebView rendering process crashed!");
   
           // In this example, the app itself crashes after detecting that the
           // renderer crashed. If you choose to handle the crash more gracefully
           // and allow your app to continue executing, you should 1) destroy the
           // current WebView instance, 2) specify logic for how the app can
           // continue executing, and 3) return "true" instead.
           return false;
       }
   

Answer 1

我已经实现了这个方法，并且不区分渲染器崩溃或被系统杀死。就应用而言，结果是相同的——webview 不可用，如果此方法返回false，应用也会被杀死。

我在 Fragment/Activity 创建期间初始化的 Fragment（或 Activity）中维护对 WebView 和两个布局根视图的引用。

        m_homeWebSwipe = v.findViewById(R.id.homeWebViewSwipe);
        m_homeWebView = v.findViewById(R.id.homeWebView);
        initializeWebView(m_homeWebView);

我的 WebView 是 SwipeRefreshLayout 的子项。布局 XML 并不重要，但供参考：

<?xml version="1.0" encoding="utf-8"?>
<androidx.swiperefreshlayout.widget.SwipeRefreshLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/homeWebViewSwipe"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <WebView
        android:id="@+id/homeWebView"
        android:layout_width="match_parent"
        android:layout_height="match_parent" >
    </WebView>
</androidx.swiperefreshlayout.widget.SwipeRefreshLayout>

这里的关键是 WebView 包含在视图根目录的 Layout 容器中。

在接收到onRenderProcessGone 事件时，目标是重新创建一个包含新 WebView 的功能视图（它将有一个与之关联的新渲染器进程）。

            @Override
            public boolean onRenderProcessGone(final WebView view, RenderProcessGoneDetail detail) {
                // Renderer was killed or died, recreate the webview
                Log.e("HomeWebView", "web content rendering process killed - resetting WebView: " + view.hashCode());

                // Only handle our WebView
                if (m_homeWebView.equals(view)) {
                    // Get the parent container of the inflated layout
                    ViewGroup container = (ViewGroup) m_homeWebSwipe.getParent();
                    ViewGroup.LayoutParams params = container.getLayoutParams();
                    // Remove the inflated view from the container and cleanup
                    // the dead webview specifically (if it is not GC'ed it will cause
                    // problems later, the next time the renderer dies)
                    container.removeView(m_homeWebSwipe);
                    m_homeWebSwipe = null;
                    m_homeWebView = null;
                    view.destroy();
                    // Reinflate the view layout and add it back into the container
                    View v = getLayoutInflater().inflate(R.layout.home_webview_screen, container, false);
                    m_homeWebSwipe = v.findViewById(R.id.homeWebViewSwipe);
                    m_homeWebView = v.findViewById(R.id.homeWebView);
                    // Initialise webview here, same as when it was originally created                    
                    initializeWebView(m_homeWebView);
                    assert(getActivity() != null);
                    getActivity().setContentView(v, params);
                    // reload the displayed page, or load a new page here
                    reloadPage();
                    return true; // The app continues executing.
                }
                return false; // the app is killed
            }

您可以通过安排 WebView 加载 URL chrome://crash

来测试 onRenderProcessGone 方法中的代码