ARouter 梳理
ARouter作为项目组件化的一个非常重要的工具，实现了很大的解耦
原理：
简单调用
@Route(path = "/test/activity1", name = "测试用 Activity")
public class Test1Activity extends AppCompatActivity {
path = "/test/activity1" 代理了两部分： group: test , path:/test/activity1
代码中通过 RouteMeta 这个类与path 作为映射关系
1 关于module的注册：
Arouter通过在编译器，扫描需要注册的类，如上面的Test1Activity ，然后生成相应的注册代码
如下代码是Arouter编译器生成的：
/**
* DO NOT EDIT THIS FILE!!! IT WAS GENERATED BY AROUTER. */
public class ARouter$$Group$$module implements IRouteGroup {
@Override
public void loadInto(Map atlas) {
atlas.put("/module/1", RouteMeta.build(RouteType.ACTIVITY, TestModuleActivity.class, "/module/1", "module", null, -1, -2147483648));
}
} 关注module的自动注册，ARouter通过asm 代码注入的方式，在编译期向LogisticsCenter.java的loadRouterMap 方法注入代码
如下：
private static void loadRouterMap() {
registerByPlugin = false;
//auto generate register code by gradle plugin: arouter-auto-register
// looks like below:
// registerRouteRoot(new ARouter..Root..modulejava());
// registerRouteRoot(new ARouter..Root..modulekotlin());
}
在ARouter初始化时，将需要的module进行注册
以上就是ARouter的注册逻辑，可以看出ARouter在编译期做了很多的生气，包括module的自动注入 ，Activity的自动注入等
2 调用逻辑：
先猜想一下如何调用：
1） 调用方传入参数以及对应的url
2) 处理逻辑找对对应的被调用发
3） 启动activity或者拿到fragment或者IProvider的实现者
ARouter.getInstance()
.build("/kotlin/test")
.withString("name", "老王")
.withInt("age", 23)
.navigation();这段代码就是启动activity的逻辑 ，最终的处理逻辑如下：
// 寻找目标 _Arouter.java
public synchronized static void completion(Postcard postcard) {
if (null == postcard) {
throw new NoRouteFoundException(TAG + "No postcard!");
}
RouteMeta routeMeta = Warehouse.routes.get(postcard.getPath());
if (null == routeMeta) { // Maybe its does't exist, or didn't load.
Class 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 {
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 resultMap = TextUtils.splitQueryParameters(rawUri);
Map paramsType = routeMeta.getParamsType();
if (MapUtils.isNotEmpty(paramsType)) {
// Set value by its type, just for params which annotation by @Param
for (Map.Entry 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());
}
switch (routeMeta.getType()) {
case PROVIDER: // if the route is provider, should find its instance
// Its provider, so it must implement IProvider
Class providerMeta = (Class) 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;
}
}
} 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;
}
try {
LogisticsCenter.completion(postcard);
} catch (NoRouteFoundException ex) {
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) {
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);
}
if (!postcard.isGreenChannel()) { // It must be run in async thread, maybe interceptor cost too mush time made ANR.
interceptorService.doInterceptions(postcard, new InterceptorCallback() {
/**
* Continue process
*
* @param postcard route meta
*/
@Override
public void onContinue(Postcard postcard) {
_navigation(context, 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) {
callback.onInterrupt(postcard);
}
logger.info(Consts.TAG, "Navigation failed, termination by interceptor : " + exception.getMessage());
}
});
} else {
return _navigation(context, postcard, requestCode, callback);
}
return null;
}
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);
}
不支持fragment.startActivity
// 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;
}
将所有module的Router的Path集中在一个公共的module中
相关知识：1 编译期注解的处理，APT,JavaAssist, 2 编译期对组件的自动注册
ASM链接：https://mp.weixin.qq.com/s?__biz=MzA5MzI3NjE2MA==&mid=2650244795&idx=1&sn=cdfc4acec8b0d2b5c82fd9d884f32f09&chksm=886377d4bf14fec2fc822cd2b3b6069c36cb49ea2814d9e0e2f4a6713f4e86dfc0b1bebf4d39&mpshare=1&scene=1&srcid=1217NjDpKNvdgalsqBQLJXjX%23rd
JavaAssist:https://www.jianshu.com/p/dca3e2c8608a
总线型组件化框架：https://github.com/luckybilly/CC
Android SPI（Service Provider Interface）机制：https://blog.csdn.net/xiaohanluo/article/details/71515678