一图抵千言《ARouter简明扼要原理分析》

<code class="javascript">apply plugin: 'kotlin-kapt'defaultConfig{ javaCompileOptions {   annotationProcessorOptions {   //AROUTER_MODULE_NAME必配项 用于拼接生成文件名 AROUTER_GENERATE_DOC    // AROUTER_GENERATE_DOC = enable 生成Json文档   // 生成的文档路径 : build/generated/source/apt/(debug or release)/com/alibaba/android/arouter/docs/arouter-map-of-${moduleName}.json   arguments = [AROUTER_MODULE_NAME:project_name,AROUTER_GENERATE_DOC:"enable"]     }   }}dependencies{  api 'com.alibaba:arouter-api:1.5.0'  kapt 'com.alibaba:arouter-compiler:1.2.2'}</code>

<code class="javascript">//项目根目录build.gradledependencies {  classpath "com.alibaba:arouter-register:1.0.2"}</code>

<code class="javascript">@Route(path = "/kotlin/test")class KotlinTestActivity : Activity() {    @Autowired    @JvmField var name: String? = null    @Autowired    @JvmField var age: Int? = 0    override fun onCreate(savedInstanceState: Bundle?) {        ARouter.getInstance().inject(this)  // Start auto inject.        super.onCreate(savedInstanceState)        setContentView(R.layout.activity_kotlin_test)        content.text = "name = $name, age = $age"    }}</code>

<code class="javascript">public class KotlinTestActivity$$ARouter$$Autowired implements ISyringe {  private SerializationService serializationService;  @Override  public void inject(Object target) {    serializationService = ARouter.getInstance().navigation(SerializationService.class);    KotlinTestActivity substitute = (KotlinTestActivity)target;    substitute.name = substitute.getIntent().getExtras() == null ? substitute.name : substitute.getIntent().getExtras().getString("name", substitute.name);    substitute.age = substitute.getIntent().getIntExtra("age", substitute.age);  }}</code>

<code class="javascript">  //初始化  ARouter.init(getApplication());    _ARouter.init(application)     LogisticsCenter.init(mContext, executor)  </code>

<code class="javascript">public synchronized static void init(Context context, ThreadPoolExecutor tpe) throws HandlerException {        mContext = context;        executor = tpe;        try {            long startInit = System.currentTimeMillis();            //load by plugin first            loadRouterMap();            if (registerByPlugin) {                logger.info(TAG, "Load router map by arouter-auto-register plugin.");            } else {                //1 生成文件所有文件的全类名字符串集合                Set<String> routerMap;                // It will rebuild router map every times when debuggable.                if (ARouter.debuggable() || PackageUtils.isNewVersion(context)) {                    logger.info(TAG, "Run with debug mode or new install, rebuild router map.");                    // These class was generated by arouter-compiler.                    //2. 赋值集合                    routerMap = ClassUtils.getFileNameByPackageName(mContext, ROUTE_ROOT_PAKCAGE);                    if (!routerMap.isEmpty()) {                        context.getSharedPreferences(AROUTER_SP_CACHE_KEY, Context.MODE_PRIVATE).edit().putStringSet(AROUTER_SP_KEY_MAP, routerMap).apply();                    }                    PackageUtils.updateVersion(context);    // Save new version name when router map update finishes.                } else {                    logger.info(TAG, "Load router map from cache.");                    routerMap = new HashSet<>(context.getSharedPreferences(AROUTER_SP_CACHE_KEY, Context.MODE_PRIVATE).getStringSet(AROUTER_SP_KEY_MAP, new HashSet<String>()));                }                logger.info(TAG, "Find router map finished, map size = " + routerMap.size() + ", cost " + (System.currentTimeMillis() - startInit) + " ms.");                startInit = System.currentTimeMillis();                 //3. 遍历集合                for (String className : routerMap) {                // 这里装在了3中类别的文件： (1) Root文件                    if (className.startsWith(ROUTE_ROOT_PAKCAGE + DOT + SDK_NAME + SEPARATOR + SUFFIX_ROOT)) {                        // This one of root elements, load root.                        ((IRouteRoot) (Class.forName(className).getConstructor().newInstance())).loadInto(Warehouse.groupsIndex);                        //(2) Interceptor 文件                    } else if (className.startsWith(ROUTE_ROOT_PAKCAGE + DOT + SDK_NAME + SEPARATOR + SUFFIX_INTERCEPTORS)) {                        // Load interceptorMeta                        ((IInterceptorGroup) (Class.forName(className).getConstructor().newInstance())).loadInto(Warehouse.interceptorsIndex);                         // //(3) Provider 文件                      } else if (className.startsWith(ROUTE_ROOT_PAKCAGE + DOT + SDK_NAME + SEPARATOR + SUFFIX_PROVIDERS)) {                        // Load providerIndex                        ((IProviderGroup) (Class.forName(className).getConstructor().newInstance())).loadInto(Warehouse.providersIndex);                    }                }            }            logger.info(TAG, "Load root element finished, cost " + (System.currentTimeMillis() - startInit) + " ms.");            if (Warehouse.groupsIndex.size() == 0) {                logger.error(TAG, "No mapping files were found, check your configuration please!");            }            if (ARouter.debuggable()) {                logger.debug(TAG, String.format(Locale.getDefault(), "LogisticsCenter has already been loaded, GroupIndex[%d], InterceptorIndex[%d], ProviderIndex[%d]", Warehouse.groupsIndex.size(), Warehouse.interceptorsIndex.size(), Warehouse.providersIndex.size()));            }        } catch (Exception e) {            throw new HandlerException(TAG + "ARouter init logistics center exception! [" + e.getMessage() + "]");        }    }</code>

<code class="javascript">public class ARouter$$Providers$$modulejava implements IProviderGroup {  @Override  public void loadInto(Map<String, RouteMeta> providers) {    providers.put("com.alibaba.android.arouter.demo.service.HelloService", RouteMeta.build(RouteType.PROVIDER, HelloServiceImpl.class, "/yourservicegroupname/hello", "yourservicegroupname", null, -1, -2147483648));    providers.put("com.alibaba.android.arouter.facade.service.SerializationService", RouteMeta.build(RouteType.PROVIDER, JsonServiceImpl.class, "/yourservicegroupname/json", "yourservicegroupname", null, -1, -2147483648));    providers.put("com.alibaba.android.arouter.demo.module1.testservice.SingleService", RouteMeta.build(RouteType.PROVIDER, SingleService.class, "/yourservicegroupname/single", "yourservicegroupname", null, -1, -2147483648));  }}</code>

<code class="javascript">public static Set<String> getFileNameByPackageName(Context context, final String packageName) throws PackageManager.NameNotFoundException, IOException, InterruptedException {        final Set<String> classNames = new HashSet<>();        List<String> paths = getSourcePaths(context);        //线程同步        final CountDownLatch parserCtl = new CountDownLatch(paths.size());        for (final String path : paths) {            DefaultPoolExecutor.getInstance().execute(new Runnable() {                @Override                public void run() {                //Dex文件                    DexFile dexfile = null;                    try {                        if (path.endsWith(EXTRACTED_SUFFIX)) {                            //NOT use new DexFile(path), because it will throw "permission error in /data/dalvik-cache"                            dexfile = DexFile.loadDex(path, path + ".tmp", 0);                        } else {                            dexfile = new DexFile(path);                        }                        Enumeration<String> dexEntries = dexfile.entries();                        while (dexEntries.hasMoreElements()) {                            String className = dexEntries.nextElement();                            //核心判断 packageName是我们上面传入的参数ROUTE_ROOT_PAKCAGE = "com.alibaba.android.arouter.routes"                            if (className.startsWith(packageName)) {                                classNames.add(className);                            }                        }                    } catch (Throwable ignore) {                        Log.e("ARouter", "Scan map file in dex files made error.", ignore);                    } finally {                        if (null != dexfile) {                            try {                                dexfile.close();                            } catch (Throwable ignore) {                            }                        }                        //也就是说，如果初始化加载流程没有走完，路由操作将会阻塞，知道加载流程完成                        parserCtl.countDown();                    }                }            });        }        parserCtl.await();        Log.d(Consts.TAG, "Filter " + classNames.size() + " classes by packageName <" + packageName + ">");        return classNames;    }</code>

<code class="javascript">class Warehouse {    // Cache route and metas      //groupsIndex 装载ARouter$$Root$$moduleName 中的Root文件  <groupName,Group.class>    static Map<String, Class<? extends IRouteGroup>> groupsIndex = new HashMap<>();    //routes 按需加载完成后 把加载的数据存到routes 集合中，等项目中用到的时候，找到集合中需要的元素 再去实例化对象    static Map<String, RouteMeta> routes = new HashMap<>();    // Cache provider   //项目中用到的时候，找到集合中需要的元素 再去实例化对象     static Map<Class, IProvider> providers = new HashMap<>();    // //每个服务的原始信息加载完成后存放到这里    static Map<String, RouteMeta> providersIndex = new HashMap<>();    // Cache interceptor       static Map<Integer, Class<? extends IInterceptor>> interceptorsIndex = new UniqueKeyTreeMap<>("More than one interceptors use same priority [%s]");    static List<IInterceptor> interceptors = new ArrayList<>();    static void clear() {        routes.clear();        groupsIndex.clear();        providers.clear();        providersIndex.clear();        interceptors.clear();        interceptorsIndex.clear();    }}</code>

<code class="javascript">    ARouter.getInstance()                        .build("/kotlin/test")                        .withString("name", "老王")                        .withInt("age", 23)                        .navigation();</code>

<code class="javascript">   protected Postcard build(String path) {        if (TextUtils.isEmpty(path)) {            throw new HandlerException(Consts.TAG + "Parameter is invalid!");        } else {        // 重定向路由路径Service 如果想自定义 则实现PathReplaceService             PathReplaceService pService = ARouter.getInstance().navigation(PathReplaceService.class);            if (null != pService) {            //通过forString(path) 返回修改后的Path                path = pService.forString(path);            }            //继续往下走             return build(path, extractGroup(path), true);        }    }   </code>

<code class="javascript"> private String extractGroup(String path) {        if (TextUtils.isEmpty(path) || !path.startsWith("/")) {            throw new HandlerException(Consts.TAG + "Extract the default group failed, the path must be start with '/' and contain more than 2 '/'!");        }        try {        //关键代码 defaultGroup 默认分组 以路由路径 第一个节点为分组名称            String defaultGroup = path.substring(1, path.indexOf("/", 1));            if (TextUtils.isEmpty(defaultGroup)) {                throw new HandlerException(Consts.TAG + "Extract the default group failed! There's nothing between 2 '/'!");            } else {                return defaultGroup;            }        } catch (Exception e) {            logger.warning(Consts.TAG, "Failed to extract default group! " + e.getMessage());            return null;        }    }</code>

<code class="javascript">  protected Postcard build(String path, String group, Boolean afterReplace) {        if (TextUtils.isEmpty(path) || TextUtils.isEmpty(group)) {            throw new HandlerException(Consts.TAG + "Parameter is invalid!");        } else {            if (!afterReplace) {                PathReplaceService pService = ARouter.getInstance().navigation(PathReplaceService.class);                if (null != pService) {                    path = pService.forString(path);                }            }            return new Postcard(path, group);        }    }</code>

<code class="javascript"> protected Object navigation(final Context context, final Postcard postcard, final int requestCode, final NavigationCallback callback) {        PretreatmentService pretreatmentService = ARouter.getInstance().navigation(PretreatmentService.class);        if (null != pretreatmentService && !pretreatmentService.onPretreatment(context, postcard)) {            // Pretreatment failed, navigation canceled.            return null;        }        // Set context to postcard.        postcard.setContext(null == context ? mContext : context);        try {        //给Postcard赋值其他数据            LogisticsCenter.completion(postcard);        } catch (NoRouteFoundException ex) {//出现异常的情况            logger.warning(Consts.TAG, ex.getMessage());            if (debuggable()) {                // Show friendly tips for user.                runInMainThread(new Runnable() {                    @Override                    public void run() {                        Toast.makeText(mContext, "There's no route matched!\n" +                                " Path = [" + postcard.getPath() + "]\n" +                                " Group = [" + postcard.getGroup() + "]", Toast.LENGTH_LONG).show();                    }                });            }            if (null != callback) {            // 路由回调 如果不为空                callback.onLost(postcard);            } else {                // No callback for this invoke, then we use the global degrade service.                //反射创建全局降级服务  回调 onLost方法                DegradeService degradeService = ARouter.getInstance().navigation(DegradeService.class);                if (null != degradeService) {                    degradeService.onLost(context, postcard);                }            }            return null;        }        if (null != callback) {        //回调路由成功的方法            callback.onFound(postcard);        }         //如果绿色通道为false 则添加拦截器         if (!postcard.isGreenChannel()) {   // It must be run in async thread, maybe interceptor cost too mush time made ANR.        // 运行在线程池中            interceptorService.doInterceptions(postcard, new InterceptorCallback() {                /**                 * Continue process                 *                 * @param postcard route meta                 */                @Override                public void onContinue(Postcard postcard) {                //继续处理完成后继续向下执行                     _navigation(postcard, requestCode, callback);                }                /**                 * Interrupt process, pipeline will be destory when this method called.                 *                 * @param exception Reson of interrupt.                 */                @Override                public void onInterrupt(Throwable exception) {                    if (null != callback) {                    //打断路由 停止路由                        callback.onInterrupt(postcard);                    }                    logger.info(Consts.TAG, "Navigation failed, termination by interceptor : " + exception.getMessage());                }            });        } else {         //继续处理完成后继续向下执行             return _navigation(postcard, requestCode, callback);        }        return null;    }</code>

<code class="javascript">public synchronized static void completion(Postcard postcard) {        if (null == postcard) {            throw new NoRouteFoundException(TAG + "No postcard!");        }        //routes是加载信息 但为实例化对象 之前提过  所以这里第一次肯定为空        RouteMeta routeMeta = Warehouse.routes.get(postcard.getPath());        if (null == routeMeta) {            // Maybe its does't exist, or didn't load.            if (!Warehouse.groupsIndex.containsKey(postcard.getGroup())) {                throw new NoRouteFoundException(TAG + "There is no route match the path [" + postcard.getPath() + "], in group [" + postcard.getGroup() + "]");            } else {                // Load route and cache it into memory, then delete from metas.                try {                    if (ARouter.debuggable()) {                        logger.debug(TAG, String.format(Locale.getDefault(), "The group [%s] starts loading, trigger by [%s]", postcard.getGroup(), postcard.getPath()));                    }                    //对Warehouse.routes初始化 实例化分组对象 获取数据                    addRouteGroupDynamic(postcard.getGroup(), null);                    if (ARouter.debuggable()) {                        logger.debug(TAG, String.format(Locale.getDefault(), "The group [%s] has already been loaded, trigger by [%s]", postcard.getGroup(), postcard.getPath()));                    }                } catch (Exception e) {                    throw new HandlerException(TAG + "Fatal exception when loading group meta. [" + e.getMessage() + "]");                }                //重新调用自己                completion(postcard);   // Reload            }        } else {        //给postcard赋值其他信息            postcard.setDestination(routeMeta.getDestination());            postcard.setType(routeMeta.getType());            postcard.setPriority(routeMeta.getPriority());            postcard.setExtra(routeMeta.getExtra());            Uri rawUri = postcard.getUri();            if (null != rawUri) {   // Try to set params into bundle.                Map<String, String> resultMap = TextUtils.splitQueryParameters(rawUri);                Map<String, Integer> paramsType = routeMeta.getParamsType();                if (MapUtils.isNotEmpty(paramsType)) {                    // Set value by its type, just for params which annotation by @Param                    for (Map.Entry<String, Integer> params : paramsType.entrySet()) {                        setValue(postcard,                                params.getValue(),                                params.getKey(),                                resultMap.get(params.getKey()));                    }                    // Save params name which need auto inject.                    postcard.getExtras().putStringArray(ARouter.AUTO_INJECT, paramsType.keySet().toArray(new String[]{}));                }                // Save raw uri                postcard.withString(ARouter.RAW_URI, rawUri.toString());            }             //类型判断 PROVIDER类型实例化对象 PROVIDER/FRAGMENT默认开启通道，不经过拦截            switch (routeMeta.getType()) {                case PROVIDER:  // if the route is provider, should find its instance                    // Its provider, so it must implement IProvider                    Class<? extends IProvider> providerMeta = (Class<? extends IProvider>) routeMeta.getDestination();                    IProvider instance = Warehouse.providers.get(providerMeta);                    if (null == instance) { // There's no instance of this provider                        IProvider provider;                        try {                            provider = providerMeta.getConstructor().newInstance();                            provider.init(mContext);                            Warehouse.providers.put(providerMeta, provider);                            instance = provider;                        } catch (Exception e) {                            logger.error(TAG, "Init provider failed!", e);                            throw new HandlerException("Init provider failed!");                        }                    }                    postcard.setProvider(instance);                    postcard.greenChannel();    // Provider should skip all of interceptors                    break;                case FRAGMENT:                    postcard.greenChannel();    // Fragment needn't interceptors                default:                    break;            }        }    } public synchronized static void addRouteGroupDynamic(String groupName, IRouteGroup group) throws NoSuchMethodException, IllegalAccessException, InvocationTargetException, InstantiationException {        if (Warehouse.groupsIndex.containsKey(groupName)){            // If this group is included, but it has not been loaded            // load this group first, because dynamic route has high priority.            //对Warehouse.routes初始化 实例化分组对象 获取数据            Warehouse.groupsIndex.get(groupName).getConstructor().newInstance().loadInto(Warehouse.routes);            Warehouse.groupsIndex.remove(groupName);        }        // cover old group.        if (null != group) {            group.loadInto(Warehouse.routes);        }    }</code>

<code class="javascript">  private Object _navigation(final Postcard postcard, final int requestCode, final NavigationCallback callback) {        final Context currentContext = postcard.getContext();//判断路由类型        switch (postcard.getType()) {            case ACTIVITY:                // Build intent                final Intent intent = new Intent(currentContext, postcard.getDestination());                intent.putExtras(postcard.getExtras());                // Set flags.                int flags = postcard.getFlags();                if (0 != flags) {                    intent.setFlags(flags);                }                // Non activity, need FLAG_ACTIVITY_NEW_TASK                if (!(currentContext instanceof Activity)) {                //context如果是Application 那么新建任务栈                    intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);                }                // Set Actions                String action = postcard.getAction();                if (!TextUtils.isEmpty(action)) {                    intent.setAction(action);                }                // Navigation in main looper.                runInMainThread(new Runnable() {                    @Override                    public void run() {                    //Activity则调用startActivity                        startActivity(requestCode, currentContext, intent, postcard, callback);                    }                });                break;            case PROVIDER:            //返回LogisticsCenter.completion(postcard)方法中创建的对象                return postcard.getProvider();            case BOARDCAST:            case CONTENT_PROVIDER:            case FRAGMENT:                Class<?> fragmentMeta = postcard.getDestination();                try {                    Object instance = fragmentMeta.getConstructor().newInstance();                    if (instance instanceof Fragment) {                        ((Fragment) instance).setArguments(postcard.getExtras());                    } else if (instance instanceof android.support.v4.app.Fragment) {                        ((android.support.v4.app.Fragment) instance).setArguments(postcard.getExtras());                    } //反射返回fragment实例                    return instance;                } catch (Exception ex) {                    logger.error(Consts.TAG, "Fetch fragment instance error, " + TextUtils.formatStackTrace(ex.getStackTrace()));                }            case METHOD:            case SERVICE:            default:                return null;        }        return null;    }</code>