有关cordova框架作为插件接入，报错：Faild create webview

[senda58]

详细的报错信息如下：

Caused by: java.lang.RuntimeException: java.lang.RuntimeException: Failed to create webview.
at com.tencent.shadow.core.loader.delegates.ShadowActivityDelegate.onCreate(ShadowActivityDelegate.kt:159)
at com.tencent.shadow.core.runtime.container.PluginContainerActivity.onCreate(PluginContainerActivity.java:85)
at android.app.Activity.performCreate(Activity.java:7802)
at android.app.Activity.performCreate(Activity.java:7791)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1299)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3245)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409) 
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83) 
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) 
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016) 
at android.os.Handler.dispatchMessage(Handler.java:107) 
at android.os.Looper.loop(Looper.java:214) 
at android.app.ActivityThread.main(ActivityThread.java:7356) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930) 
Caused by: java.lang.RuntimeException: Failed to create webview.
at org.apache.cordova.CordovaWebViewImpl.createEngine(CordovaWebViewImpl.java:84)
at org.apache.cordova.CordovaActivity.makeWebViewEngine(CordovaActivity.java:209)
at org.apache.cordova.CordovaActivity.makeWebView(CordovaActivity.java:205)
at org.apache.cordova.CordovaActivity.init(CordovaActivity.java:149)
at org.apache.cordova.CordovaActivity.loadUrl(CordovaActivity.java:227)
at com.example.hello.MainActivity.onCreate(MainActivity.java:39)
at com.tencent.shadow.core.loader.delegates.ShadowActivityDelegate.onCreate(ShadowActivityDelegate.kt:156)
at com.tencent.shadow.core.runtime.container.PluginContainerActivity.onCreate(PluginContainerActivity.java:85) 
at android.app.Activity.performCreate(Activity.java:7802) 
at android.app.Activity.performCreate(Activity.java:7791) 
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1299) 
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3245) 
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409) 
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83) 
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) 
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016) 
at android.os.Handler.dispatchMessage(Handler.java:107) 
at android.os.Looper.loop(Looper.java:214) 
at android.app.ActivityThread.main(ActivityThread.java:7356) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930) 
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Constructor.newInstance0(Native Method)
at java.lang.reflect.Constructor.newInstance(Constructor.java:343)
at org.apache.cordova.CordovaWebViewImpl.createEngine(CordovaWebViewImpl.java:82)
at org.apache.cordova.CordovaActivity.makeWebViewEngine(CordovaActivity.java:209) 
at org.apache.cordova.CordovaActivity.makeWebView(CordovaActivity.java:205) 
at org.apache.cordova.CordovaActivity.init(CordovaActivity.java:149) 
at org.apache.cordova.CordovaActivity.loadUrl(CordovaActivity.java:227) 
at com.example.hello.MainActivity.onCreate(MainActivity.java:39) 
at com.tencent.shadow.core.loader.delegates.ShadowActivityDelegate.onCreate(ShadowActivityDelegate.kt:156) 
at com.tencent.shadow.core.runtime.container.PluginContainerActivity.onCreate(PluginContainerActivity.java:85) 
at android.app.Activity.performCreate(Activity.java:7802) 
at android.app.Activity.performCreate(Activity.java:7791) 
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1299) 
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3245) 
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409) 
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83) 
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) 
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016) 
at android.os.Handler.dispatchMessage(Handler.java:107) 
at android.os.Looper.loop(Looper.java:214) 
at android.app.ActivityThread.main(ActivityThread.java:7356) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930) 
Caused by: java.lang.ClassCastException: android.webkit.WebViewClient cannot be cast to org.apache.cordova.engine.SystemWebViewClient
at org.apache.cordova.engine.SystemWebView.setWebViewClient(SystemWebView.java:70)
at com.tencent.shadow.core.runtime.ShadowWebView.init(ShadowWebView.java:82)
at com.tencent.shadow.core.runtime.ShadowWebView.(ShadowWebView.java:61)

[senda58]

大概分析了一下原因，在cordova 框架中
public class SystemWebView extends WebView ，而插件在编译时，将WebView 替换了ShadowWebview 导致初始化时，转化类型出错。这个怎么改呢？

@shifujun 能给讲讲，宿主加载weview 资源文件的原理么？ 插件编译时将WebView 替换了ShadowWebview 意义在于什么呢？

[shifujun]

webview的处理原因可以blame一下shadowwebview那个文件看到提交记录。

这里的bug应该是 ebb33a8 处理时没考虑到子类可能需要对应的client子类。

解决这个bug需要再review一下init时需要初始化client的原因。以及如何确定client子类，如何构造client子类对象。

[senda58]

这个是cordova框架自带的。还是没明白该咋改， 我想知道插件编译时将WebView 替换了ShadowWebview 意义在于什么呢？
@shifujun

[shifujun]

你翻阅ShadowWebview的提交记录和实现就会发现它和从assets中加载url的关系了。

[senda58]

@shifujun 为什么不能 使用ShdowWebView子类自己的setWebviewClient 呢？ 也就是说 使用插件自己webview的逻辑呢？

下面是cordova框架 自带的webview子类，麻烦大佬给分析一下，谢谢了

        public class SystemWebView extends WebView implements CordovaWebViewEngine.EngineView {
            private SystemWebViewClient viewClient;
            SystemWebChromeClient chromeClient;
            private SystemWebViewEngine parentEngine;
            private CordovaInterface cordova;
        
            public SystemWebView(Context context) {
                this(context, null);
            }
        
            public SystemWebView(Context context, AttributeSet attrs) {
                super(context, attrs);
            }
        
            // Package visibility to enforce that only SystemWebViewEngine should call this method.
            void init(SystemWebViewEngine parentEngine, CordovaInterface cordova) {
                this.cordova = cordova;
                this.parentEngine = parentEngine;
                if (this.viewClient == null) {
                    setWebViewClient(new SystemWebViewClient(parentEngine));
                }
        
                if (this.chromeClient == null) {
                    setWebChromeClient(new SystemWebChromeClient(parentEngine));
                }
            }
        
            @Override
            public CordovaWebView getCordovaWebView() {
                return parentEngine != null ? parentEngine.getCordovaWebView() : null;
            }
        
            @Override
            public void setWebViewClient(WebViewClient client) {
                viewClient = (SystemWebViewClient)client;
                super.setWebViewClient(client);
            }
        
            @Override
            public void setWebChromeClient(WebChromeClient client) {
                chromeClient = (SystemWebChromeClient)client;
                super.setWebChromeClient(client);
            }
        
            @Override
            public boolean dispatchKeyEvent(KeyEvent event) {
                Boolean ret = parentEngine.client.onDispatchKeyEvent(event);
                if (ret != null) {
                    return ret.booleanValue();
                }
                return super.dispatchKeyEvent(event);
            }
        }

[shifujun]

肯定是可以的，也应该使用原本业务定义的子类的。你理解错了。我们就是把WebView换成了ShadowWebView，加了一层逻辑而已。

[senda58]

@shifujun 好，谢谢 大佬，代码可以了，太厉害了！