2020-08-27发表8 分钟读完 (大约1232个字)

ARouter源码解析

0x01 init ()

ARouter 的入口，初始化SDK ARouter.init(mApplication);：

public static void init(Application application) {
  if (!hasInit) { // 避免重复初始化
    logger = _ARouter.logger; // 日志初始化
    _ARouter.logger.info(Consts.TAG, "ARouter init start.");
    hasInit = _ARouter.init(application); // 正式初始化
    if (hasInit) { // 初始化之后
      _ARouter.afterInit(); // 管理拦截器的服务 InterceptorService 初始化
    }
    _ARouter.logger.info(Consts.TAG, "ARouter init over.");
  }
}

_ARouter.init()：

protected static synchronized boolean init(Application application) {
  mContext = application; // 初始化application
  LogisticsCenter.init(mContext, executor); // 指定默认的线程池初始化
  logger.info(Consts.TAG, "ARouter init success!");
  hasInit = true;// 初始化成功
  mHandler = new Handler(Looper.getMainLooper());// 初始化mHandler
  return true;
}

LogisticsCenter.init()

1 使用 arouter-auto-register 插件自动加载 routerMap

2 手动加载的情况，release 仅第一次会去解析 routerMap，其他时候都读取 SharedPreferences

3 根据routerMap三种类型，分别缓存在Warehouse 的Map中

route and metas
provider
interceptor

// LogisticsCenter init, load all metas in memory.
public synchronized static void init(Context context, ThreadPoolExecutor tpe) throws HandlerException {
  mContext = context;
  executor = tpe; // 线程池
    //...  
    loadRouterMap();  // 插件arouter-auto-register会生成这个方法的代码实现
    if (registerByPlugin) {
      logger.info(TAG, "Load router map by arouter-auto-register plugin.");
    } else {// 不用插件手动加载routerMap
      Set<String> routerMap; // routerMap
      // Debug 模式每次更新 routerMap，并更新SharedPreferences
      if (ARouter.debuggable() || PackageUtils.isNewVersion(context)) { 
        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);
      } else {
       // 直接从 SharedPreferences 读取 routerMap
        routerMap = new HashSet<>(context.getSharedPreferences(AROUTER_SP_CACHE_KEY, Context.MODE_PRIVATE).getStringSet(AROUTER_SP_KEY_MAP, new HashSet<String>()));
      }
     //...
      for (String className : routerMap) {
        if (className.startsWith(ROUTE_ROOT_PAKCAGE + DOT + SDK_NAME + SEPARATOR + SUFFIX_ROOT)) {
          // Load root
          ((IRouteRoot) (Class.forName(className).getConstructor().newInstance())).loadInto(Warehouse.groupsIndex);
        } else if (className.startsWith(ROUTE_ROOT_PAKCAGE + DOT + SDK_NAME + SEPARATOR + SUFFIX_INTERCEPTORS)) {
          // Load interceptorMeta
          ((IInterceptorGroup) (Class.forName(className).getConstructor().newInstance())).loadInto(Warehouse.interceptorsIndex);
        } else if (className.startsWith(ROUTE_ROOT_PAKCAGE + DOT + SDK_NAME + SEPARATOR + SUFFIX_PROVIDERS)) {
          // Load providerIndex
          ((IProviderGroup) (Class.forName(className).getConstructor().newInstance())).loadInto(Warehouse.providersIndex);
        }
      }
    }
   //...
}

class Warehouse 缓存三种类型的数据

class Warehouse {
  // Cache route and metas
  static Map<String, Class<? extends IRouteGroup>> groupsIndex = new HashMap<>();
  static Map<String, RouteMeta> routes = new HashMap<>();

  // Cache provider
  static Map<Class, IProvider> providers = new HashMap<>();
  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<>();
}

总结来说，init过程就是把所有注解的信息加载内存中，并且完成所有拦截器的初始化。

发起路由操作 ARouter.getInstance().build("/test/activity").navigation();

1
2
3

public Postcard build(String path) {
  return _ARouter.getInstance().build(path);
}

都是单例设计，最后调用 _ARouter 单例的 build()

protected Postcard build(String path) {
  //... 
  PathReplaceService pService = ARouter.getInstance().navigation(PathReplaceService.class);
  if (null != pService) {
    path = pService.forString(path);
  }
  return build(path, extractGroup(path));
}
protected Postcard build(String path, String group) {
  //... 
  PathReplaceService pService = ARouter.getInstance().navigation(PathReplaceService.class);
  if (null != pService) {
    path = pService.forString(path);
  }
  return new Postcard(path, group);
}

PathReplaceService，它是继承IProvider的接口，它是预留给用户实现路径动态变化功能。

Postcard 是一个继承自 RouteMeta 的数据 Bean。

public final class Postcard extends RouteMeta {
  // Base
  private Uri uri;
  private Object tag;             // A tag prepare for some thing wrong.
  private Bundle mBundle;         // Data to transform
  private int flags = -1;         // Flags of route
  private int timeout = 300;      // Navigation timeout, TimeUnit.Second
  private IProvider provider;     // It will be set value, if this postcard was provider.
  private boolean greenChannel;
  private SerializationService serializationService;

  // Animation
  private Bundle optionsCompat;    // The transition animation of activity
  private int enterAnim = -1;
  private int exitAnim = -1;
  //...
}

Postcard 对象的 navigation 方法，最终还是调用的 _Arouter 的 navigation方法。

1 PretreatmentService 进行跳转的拦截和检测

2 LogisticsCenter.completion(postcard) Postcard 加载和自解析

3 Postcard 解析异常回调 callback.onLost，若 callback 为空则 DegradeService 降级回调处理

4 Postcard 处理结束，回调 callback.onFound(postcard)

5 GreenChannel 的 navigation，直接执行 _navigation 路由

6 非 GreenChannel 的 navigation，异步执行注入拦截器。拦截之后回调 callback.onInterrupt, 通过所有的拦截器，则继续执行 _navigation 路由

protected Object navigation(final Context context, final Postcard postcard, final int requestCode, final NavigationCallback callback) {
  PretreatmentService pretreatmentService = ARouter.getInstance().navigation(PretreatmentService.class);
  // ....pretreatmentService拦截
  try {
    LogisticsCenter.completion(postcard);// postcard 自解析
  } catch (NoRouteFoundException ex) {
    // ....
    if (null != callback) {
      callback.onLost(postcard);
    } else {
      // No callback for this invoke, then we use the global degrade service.
      DegradeService degradeService = ARouter.getInstance().navigation(DegradeService.class);
      if (null != degradeService) {
        degradeService.onLost(context, postcard);
      }
    }
    return null;
  }

  if (null != callback) {
    callback.onFound(postcard); // Postcard 处理结束，回调 callback.onFound(postcard)
  }

  if (!postcard.isGreenChannel()) {
    interceptorService.doInterceptions(postcard, new InterceptorCallback() {
      @Override
      public void onContinue(Postcard postcard) {
        _navigation(context, postcard, requestCode, callback);
      }
      @Override
      public void onInterrupt(Throwable exception) {
        if (null != callback) {
          callback.onInterrupt(postcard);
        }
      }
    });
  } else {
    return _navigation(context, postcard, requestCode, callback);
  }

  return null;
}

_Arouter 的 _navigation 方法

1 根据 postcard.getType() 处理

2 ACTIVITY 类型，根据 postcard.getDestination() 生成一个 intent，然后 putExtras，并设置对应的 flag 和 action 执行跳转

3 PROVIDER 类型，直接返回在 LogisticsCenter.completion(postcard) 生成的 IProvider 实例

4 BOARDCAST，CONTENT_PROVIDER，FRAGMENT 类型分别返回 newInstance() 生成实例，Fragment 会 setArguments

private Object _navigation(final Context context, final Postcard postcard, final int requestCode, final NavigationCallback callback) {
 // ...
  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 (-1 != flags) {
        intent.setFlags(flags);
      } else if (!(currentContext instanceof Activity)) {    // Non activity, need less one flag.
        intent.setFlags(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() {
          startActivity(requestCode, currentContext, intent, postcard, callback);
        }
      });

      break;
    case PROVIDER:
      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());
        }

        return instance;
      } catch (Exception ex) {
       // ...
      }
    case METHOD:
    case SERVICE:
    default:
      return null;
  }
  return null;
}

ARouter源码解析

https://denchopen.github.io/blog/2020/08/27/源码解析-Arouter/

作者

Dench

发布于

2020-08-27

更新于

2020-08-27

许可协议

CC BY-NC-SA 4.0

#Android 源码

ARouter源码解析