ARouter是阿里開源的Android路由框架,主要用于解決Android應用組件化改造解耦后組件間跳轉(zhuǎn)、通信等操作。 本篇文章管中窺豹地簡單總結下ARouter的使用和源碼。
項目地址:
https://github.com/alibaba/ARouter
一、ARouter使用
1.1 框架引入
根工程build.gradle
dependencies {
//ARouter插件依賴
classpath "com.alibaba:arouter-register:1.0.2"
}
對需要路由的組件均做如下配置:build.gradle
plugins {
//引入aroute插件
id 'com.alibaba.arouter'
}
android {
defaultConfig {
//ARouter配置
javaCompileOptions {
annotationProcessorOptions {
arguments = [AROUTER_MODULE_NAME: project.getName(), AROUTER_GENERATE_DOC: "enable"]
}
}
}
}
dependencies {
//arouter庫
compileOnly("com.alibaba:arouter-api:1.5.0") {
exclude group: 'com.android.support' //排除掉support包,保證版本統(tǒng)一
}
annotationProcessor("com.alibaba:arouter-compiler:1.2.2")
}
這里arouter庫一般只在宿主中通過implementation引入,各組件只需要compileOnly
1.2 使用
完整使用參考官方文檔。
這里以一個案例簡單介紹下常用的通過服務接口實現(xiàn)解耦組件間調(diào)用
案例組件構成:
- host 宿主
- base_core 基礎組件
- ft_a 業(yè)務A組件
- ft_login 業(yè)務登錄組件
業(yè)務A組件調(diào)用登錄組件登錄功能說明:
host:宿主
public class RefApplication extends Application {
@Override
public void onCreate() {
super.onCreate();
//ARouter初始化
ARouter.init(this);
}
}
application中做ARouter初始化
base_core組件:
定義接口
public interface LoginService extends IProvider {
void login(Context context);
}
定義供外部組件統(tǒng)一調(diào)用的登錄功能包裝入口
public class LoginWrapper {
private static LoginWrapper sLoginWrapper = null;
@Autowired(name = Constants.LOGIN) // /login/login_service 至少兩級地址
protected LoginService mLoginService;
private LoginWrapper() {
ARouter.getInstance().inject(this);
}
public static LoginWrapper getInstance() {
if (sLoginWrapper == null) {
synchronized (LoginWrapper.class) {
if (sLoginWrapper == null) {
sLoginWrapper = new LoginWrapper();
}
}
}
return sLoginWrapper;
}
public void login(Context context) {
mLoginService.login(context);
}
}
ft_login組件
@Route(path = Constants.LOGIN)//與@Autowired name保持一致
public class LoginServiceImpl implements LoginService {
@Override
public void login(Context context) {
//TODO login具體功能
}
@Override
public void init(Context context) {
//實現(xiàn)IProvider init()方法,這里就是個初始化回調(diào)
}
}
ft_a組件
A組件調(diào)用登錄功能:
LoginWrapper.getInstance().login(this);
base_core業(yè)務組件都會依賴,以它作為中轉(zhuǎn)站,定義服務接口和提供具體服務執(zhí)行包裝類,不相互依賴的業(yè)務組件間通過它來統(tǒng)一獲取其他組件的功能。這里ft_a組件通過LoginWrapper調(diào)用login功能,內(nèi)部由接口LoginService通過注解的方式獲取ft_login具體實現(xiàn)LoginServiceImpl來執(zhí)行最終的login功能。下面通過這個流程來簡單看下ARouter內(nèi)部是怎么實現(xiàn)的。
二、ARouter源碼淺析
2.1 APT動態(tài)生成文件
ARouter在編譯階段通過APT動態(tài)生成一批文件:

這里Processor如何生成對應模板不鋪開分析了,這不是重點,感興趣的可以自行擼下源碼,這里簡單看下編譯生成的模板類是什么樣的:
@Router注解通過RouteProcessor生成存儲了path、group以及目標類相關映射關系的類文件:
public class ARouter$$Providers$$ft_login implements IProviderGroup {
@Override
public void loadInto(Map<String, RouteMeta> providers) {
}
}
public class ARouter$$Root$$ft_login implements IRouteRoot {
@Override
public void loadInto(Map<String, Class<? extends IRouteGroup>> routes) {
routes.put("login", ARouter$$Group$$login.class);
}
}
public class ARouter$$Group$$login implements IRouteGroup {
@Override
public void loadInto(Map<String, RouteMeta> atlas) {
atlas.put("/login/login_service", RouteMeta.build(RouteType.ACTIVITY, LoginActivity.class, "/login/login_service", "login", null, -1, -2147483648));
}
}
@Autowired注解通過AutowiredProcessor也生成相關的映射文件
public class LoginWrapper$$ARouter$$Autowired implements ISyringe {
private SerializationService serializationService;
@Override
public void inject(Object target) {
serializationService = ARouter.getInstance().navigation(SerializationService.class);
LoginWrapper substitute = (LoginWrapper)target;
substitute.mLoginService = (LoginService)ARouter.getInstance().build("/login/login_service").navigation();
}
}
2.2 ARouter初始化
ARouter.init(this)
這里ARouter作為門面,具體功能實現(xiàn)交由代理_ARouter來處理,整個init過程最終核心功能在LogisticsCenter.init(...)
public synchronized static void init(Context context, ThreadPoolExecutor tpe) throws HandlerException {
mContext = context;
executor = tpe;
try {
long startInit = System.currentTimeMillis();
//billy.qi modified at 2017-12-06
//load by plugin first
loadRouterMap();
if (registerByPlugin) {
logger.info(TAG, "Load router map by arouter-auto-register plugin.");
} else {
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.
//掃描com.alibaba.android.arouter.routes包下面包含的所有的ClassName
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();
for (String className : routerMap) {
//com.alibaba.android.arouter.routes.ARouter$$Root
if (className.startsWith(ROUTE_ROOT_PAKCAGE + DOT + SDK_NAME + SEPARATOR + SUFFIX_ROOT)) {
// This one of root elements, load root.
//這里將該文件信息加載到Warehouse對應Map中,作為內(nèi)存緩存
((IRouteRoot) (Class.forName(className).getConstructor().newInstance())).loadInto(Warehouse.groupsIndex);
//com.alibaba.android.arouter.routes.ARouter$$Interceptors
} else if (className.startsWith(ROUTE_ROOT_PAKCAGE + DOT + SDK_NAME + SEPARATOR + SUFFIX_INTERCEPTORS)) {
// Load interceptorMeta
((IInterceptorGroup) (Class.forName(className).getConstructor().newInstance())).loadInto(Warehouse.interceptorsIndex);
//com.alibaba.android.arouter.routes.ARouter$$Providers
} else if (className.startsWith(ROUTE_ROOT_PAKCAGE + DOT + SDK_NAME + SEPARATOR + SUFFIX_PROVIDERS)) {
// Load providerIndex
((IProviderGroup) (Class.forName(className).getConstructor().newInstance())).loadInto(Warehouse.providersIndex);
}
}
}
...
}
init過程主要是掃描com.alibaba.android.arouter.routes包下動態(tài)生成的類,按映射關系(組分類、多級管理,按需初始化)分類加載到內(nèi)存,由Warehouse不同的Map來保存。
這里簡單看下RouteMeta的數(shù)據(jù)結構,以及其build方法
public class RouteMeta {
private RouteType type; // 路由支持的類型:ACTIVITY、SERVICE、PROVIDER、CONTENT_PROVIDER、BOARDCAST、METHOD、FRAGMENT、UNKNOWN
private Element rawType; // Raw type of route
private Class<?> destination; // 訪問的目標類
private String path; // 路由路徑,這里指Route注解設置的path
private String group; // Group of route
private int priority = -1; // The smaller the number, the higher the priority
private int extra; // Extra data
private Map<String, Integer> paramsType; // Param type
private String name;
private Map<String, Autowired> injectConfig; // Cache inject config.
public RouteMeta() {
}
//初始化RouteMeta實例
public static RouteMeta build(RouteType type, Class<?> destination, String path, String group, Map<String, Integer> paramsType, int priority, int extra) {
return new RouteMeta(type, null, destination, null, path, group, paramsType, priority, extra);
}
然后將該實例添加到Map<String, RouteMeta> 中,key是Router path value是初始化好的RouteMeta實例。
2.3 路由的方式調(diào)用目標類的方法
LoginWrapper.getInstance().login(this);
從上面的源碼看,LoginWrapper作為包裝類,最終login方法是通過具體的service去實現(xiàn)。
那么這里就要了解如何發(fā)現(xiàn)化服務,官方介紹有兩種方式:
1) (推薦)使用依賴注入的方式發(fā)現(xiàn)服務,通過注解標注字段,即可使用,無需主動獲取
public class LoginWrapper {
@Autowired(name = Constants.LOGIN)
protected LoginService mLoginService;
private LoginWrapper() {
ARouter.getInstance().inject(this);
}
public void login(Context context) {
mLoginService.login(context);
}
}
為LoginService打上@Autowired注解,通過ARouter的inject方法直接調(diào)用APT生成的模板類:
inject方法的調(diào)用棧:
ARouter.inject ->_ARouter.inject -> AutowiredServiceImpl.autowire -> LoginWrapper$$ARouter$$Autowired.inject
public class LoginWrapper$$ARouter$$Autowired implements ISyringe {
private SerializationService serializationService;
@Override
public void inject(Object target) {
serializationService = ARouter.getInstance().navigation(SerializationService.class);
LoginWrapper substitute = (LoginWrapper)target;
substitute.mLoginService = (LoginService)ARouter.getInstance().build("/login/login_service").navigation();
}
}
2)使用依賴查找的方式發(fā)現(xiàn)服務
public class LoginWrapper {
protected LoginService mLoginService;
public void login(Context context) {
mLoginService = (LoginService) ARouter.getInstance().build(Constants.LOGIN).navigation();
mLoginService.login(context);
}
}
直接通過ARouter來查找,實現(xiàn)其實與APT生成的模板類是一樣的,只是從寫法上來說,打上@Autowired注解更簡潔,也是官方推薦的方式。
這里mLoginService最終實例對應的是ft_a中的LoginServiceImpl,通過它來實現(xiàn)具體的login功能。那么關鍵就是分析清楚如下代碼:
(LoginService) ARouter.getInstance().build(Constants.LOGIN).navigation();
從調(diào)用來看主要分兩步:
- build("/login/login_service"):
_ARouter.java
protected Postcard build(String path) {
if (TextUtils.isEmpty(path)) {
throw new HandlerException(Consts.TAG + "Parameter is invalid!");
} else {
PathReplaceService pService = ARouter.getInstance().navigation(PathReplaceService.class);
if (null != pService) {
path = pService.forString(path);
}
//構建一個攜帶 path和group兩個路由地址數(shù)據(jù)的Postcard對象
return build(path, extractGroup(path));
}
}
整個build過程實際上就是構建一個Postcard。一個Postcard 對象就對應了一次路由請求,該對象作用于本次路由全過程。
- navigation():
經(jīng)過層層調(diào)用最終核心實現(xiàn)在
com/alibaba/android/arouter/launcher/_ARouter.java
/**
* 參數(shù):
* Postcard this
* requestCode -1
* callback null
*/
protected Object navigation(final Context context, final Postcard postcard, final int requestCode, final NavigationCallback callback) {
PretreatmentService pretreatmentService = ARouter.getInstance().navigation(PretreatmentService.class);
...
//從Warehouse對應map中獲取@Router標記的目標類更多信息,完善當前Postcard
LogisticsCenter.completion(postcard);
...
//綠色通道,默認不走
if (!postcard.isGreenChannel()) { // It must be run in async thread, maybe interceptor cost too mush time made ANR.
...
} else {
return _navigation(context, postcard, requestCode, callback);
}
return null;
}
這里核心代碼就兩處:一個是通過LogisticsCenter.completion(postcard)來完善Postcard的類信息。另一個是通過_navigation來執(zhí)行對應的操作。
先看LogisticsCenter.completion()方法
public synchronized static void completion(Postcard postcard) {
if (null == postcard) {
throw new NoRouteFoundException(TAG + "No postcard!");
}
// 從倉庫的路由地址清單列表中嘗試獲取對應的RouteMeta
RouteMeta routeMeta = Warehouse.routes.get(postcard.getPath());
if (null == routeMeta) { // Maybe its does't exist, or didn't load.
// 如果前面沒獲取到,則根據(jù)一級地址,嘗試獲取對應的路由地址清單的文件類(ARouter$$Root$$工程名)
Class<? extends IRouteGroup> groupMeta = Warehouse.groupsIndex.get(postcard.getGroup()); // Load route meta.
if (null == groupMeta) {
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()));
}
IRouteGroup iGroupInstance = groupMeta.getConstructor().newInstance();
iGroupInstance.loadInto(Warehouse.routes);
Warehouse.groupsIndex.remove(postcard.getGroup());
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() + "]");
}
completion(postcard); // Reload
}
} else {
//完善postcard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());
}
//針對不同的type做不同的設置
switch (routeMeta.getType()) {
//如果是PROVIDER類型,會通過routeMeta獲取目標類,并實例化,最終由postcard.setProvider設置目標類的實例化對象
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) {
throw new HandlerException("Init provider failed! " + e.getMessage());
}
}
postcard.setProvider(instance);
postcard.greenChannel(); // Provider should skip all of interceptors
break;
case FRAGMENT:
postcard.greenChannel(); // Fragment needn't interceptors
default:
break;
}
}
}
complete主要是通過Warehouse來完善postcard信息 ,這里因為LoginService繼承的IProvider,routeMeta對應的類型為PROVIDER,這里會初始化目標類LoginServiceImpl,并通過postcard.setProvider來設置到postcard中。
再看_navigation()方法
private Object _navigation(final Context context, final Postcard postcard, final int requestCode, final NavigationCallback callback) {
final Context currentContext = null == context ? mContext : context;
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) {
logger.error(Consts.TAG, "Fetch fragment instance error, " + TextUtils.formatStackTrace(ex.getStackTrace()));
}
case METHOD:
case SERVICE:
default:
return null;
}
return null;
}
根據(jù)PostCard攜帶的類型,做相應的操作。這里因為類型為PROVIDER,返回的 postcard.getProvider(),由上面complete我們知道postcard.getProvider()獲取的是目標類LoginServiceImpl的實例。
最后再總結一張ARoute核心工作原理圖:

本篇文章從組件化經(jīng)典應用案例出發(fā),通過分析涉及的框架源碼簡單了解了ARouter的核心工作原理, 僅僅只是管中窺豹,更詳細使用和說明還參考官方文檔。完成這篇文章又到了凌晨1點多,年前的最后一篇文章,希望新的一年能沉淀出更好的自己,加油!