Android混合开发全解析

    /**
     * @hide
     */
    @SuppressWarnings("deprecation")  // for super() call into deprecated base class constructor.
    protected WebView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes,
            Map
    
    
     
      javaScriptInterfaces, boolean privateBrowsing) {
        super(context, attrs, defStyleAttr, defStyleRes);
        if (context == null) {
            throw new IllegalArgumentException("Invalid context argument");
        }
        sEnforceThreadChecking = context.getApplicationInfo().targetSdkVersion >=
                Build.VERSION_CODES.JELLY_BEAN_MR2;
        checkThread();
        if (TRACE) Log.d(LOGTAG, "WebView
     
     
      
      ");

        ensureProviderCreated();
        mProvider.init(javaScriptInterfaces, privateBrowsing);
        // Post condition of creating a webview is the CookieSyncManager.getInstance() is allowed.
        CookieSyncManager.setGetInstanceIsAllowed();
    }
     
     
    
    

    static WebViewFactoryProvider getProvider() {
        synchronized (sProviderLock) {
            // For now the main purpose of this function (and the factory abstraction) is to keep
            // us honest and minimize usage of WebView internals when binding the proxy.
            if (sProviderInstance != null) return sProviderInstance;

            final int uid = android.os.Process.myUid();
            if (uid == android.os.Process.ROOT_UID || uid == android.os.Process.SYSTEM_UID) {
                throw new UnsupportedOperationException(
                        "For security reasons, WebView is not allowed in privileged processes");
            }

            Trace.traceBegin(Trace.TRACE_TAG_WEBVIEW, "WebViewFactory.getProvider()");
            try {
                Class
    
    
     
      providerClass = getProviderClass();

                StrictMode.ThreadPolicy oldPolicy = StrictMode.allowThreadDiskReads();
                Trace.traceBegin(Trace.TRACE_TAG_WEBVIEW, "providerClass.newInstance()");
                try {
                    sProviderInstance = providerClass.getConstructor(WebViewDelegate.class)
                            .newInstance(new WebViewDelegate());
                    if (DEBUG) Log.v(LOGTAG, "Loaded provider: " + sProviderInstance);
                    return sProviderInstance;
                } catch (Exception e) {
                    Log.e(LOGTAG, "error instantiating provider", e);
                    throw new AndroidRuntimeException(e);
                } finally {
                    Trace.traceEnd(Trace.TRACE_TAG_WEBVIEW);
                    StrictMode.setThreadPolicy(oldPolicy);
                }
            } finally {
                Trace.traceEnd(Trace.TRACE_TAG_WEBVIEW);
            }
        }
    }
    
    

    private static Class
    
    
     
      getProviderClass() {
        try {
            // First fetch the package info so we can log the webview package version.
            sPackageInfo = fetchPackageInfo();
            Log.i(LOGTAG, "Loading " + sPackageInfo.packageName + " version " +
                sPackageInfo.versionName + " (code " + sPackageInfo.versionCode + ")");

            Trace.traceBegin(Trace.TRACE_TAG_WEBVIEW, "WebViewFactory.loadNativeLibrary()");
            loadNativeLibrary();
            Trace.traceEnd(Trace.TRACE_TAG_WEBVIEW);

            Trace.traceBegin(Trace.TRACE_TAG_WEBVIEW, "WebViewFactory.getChromiumProviderClass()");
            try {
                return getChromiumProviderClass();
            } catch (ClassNotFoundException e) {
                Log.e(LOGTAG, "error loading provider", e);
                throw new AndroidRuntimeException(e);
            } finally {
                Trace.traceEnd(Trace.TRACE_TAG_WEBVIEW);
            }
        } catch (MissingWebViewPackageException e) {
            // If the package doesn't exist, then try loading the null WebView instead.
            // If that succeeds, then this is a device without WebView support; if it fails then
            // swallow the failure, complain that the real WebView is missing and rethrow the
            // original exception.
            try {
                return (Class
     
     
      
      ) Class.forName(NULL_WEBVIEW_FACTORY);
            } catch (ClassNotFoundException e2) {
                // Ignore.
            }
            Log.e(LOGTAG, "Chromium WebView package does not exist", e);
            throw new AndroidRuntimeException(e);
        }
    }
     
     
    
    

    private static final String CHROMIUM_WEBVIEW_FACTORY =
            "com.android.webview.chromium.WebViewChromiumFactoryProvider";

    private static Class
    
    
     
      getChromiumProviderClass()
            throws ClassNotFoundException {
        Application initialApplication = AppGlobals.getInitialApplication();
        try {
            // Construct a package context to load the Java code into the current app.
            Context webViewContext = initialApplication.createPackageContext(
                    sPackageInfo.packageName,
                    Context.CONTEXT_INCLUDE_CODE | Context.CONTEXT_IGNORE_SECURITY);
            initialApplication.getAssets().addAssetPath(
                    webViewContext.getApplicationInfo().sourceDir);
            ClassLoader clazzLoader = webViewContext.getClassLoader();
            Trace.traceBegin(Trace.TRACE_TAG_WEBVIEW, "Class.forName()");
            try {
                return (Class
     
     
      
      ) Class.forName(CHROMIUM_WEBVIEW_FACTORY, true,
                                                                     clazzLoader);
            } finally {
                Trace.traceEnd(Trace.TRACE_TAG_WEBVIEW);
            }
        } catch (PackageManager.NameNotFoundException e) {
            throw new MissingWebViewPackageException(e);
        }
    }
     
     
    
    

    public JsCallJava (String injectedName, Class injectedCls) {
        try {
            if (TextUtils.isEmpty(injectedName)) {
                throw new Exception("injected name can not be null");
            }
            mInjectedName = injectedName;
            mMethodsMap = new HashMap
    
    
     
     ();
            //获取自身声明的所有方法（包括public private protected）， getMethods会获得所有继承与非继承的方法
            Method[] methods = injectedCls.getDeclaredMethods();
            StringBuilder sb = new StringBuilder("javascript:(function(b){console.log(\"");
            sb.append(mInjectedName);
            sb.append(" initialization begin\");var a={queue:[],callback:function(){var d=Array.prototype.slice.call(arguments,0);var c=d.shift();var e=d.shift();this.queue[c].apply(this,d);if(!e){delete this.queue[c]}}};");
            for (Method method : methods) {
                String sign;
                if (method.getModifiers() != (Modifier.PUBLIC | Modifier.STATIC) || (sign = genJavaMethodSign(method)) == null) {
                    continue;
                }
                mMethodsMap.put(sign, method);
                sb.append(String.format("a.%s=", method.getName()));
            }

            sb.append("function(){var f=Array.prototype.slice.call(arguments,0);if(f.length<1){throw\"");
            sb.append(mInjectedName);
            sb.append(" call error, message:miss method name\"}var e=[];for(var h=1;h