基于arouter-api:1.3.1 arouter-compiler:1.1.4
ARouter 為Android平臺(tái)中對(duì)頁面、服務(wù)提供路由功能的中間件
下面從源碼分析為什么只用通過一個(gè)注解就可以得到相應(yīng)的Activity或Fragment
//服務(wù)module中的FragmentService
@Route(path = "/service/fragmentService")
public class FragmentService{}
//服務(wù)module中的TestActivity
@Route(path = "/service/test")
public class TestActivity extends BaseActivity{}
//主APP中獲取FragmentService實(shí)例
Fragment serviceFragment = (Fragment) ARouter.getInstance().build("/service/fragmentService").navigation();
//主APP中跳轉(zhuǎn)服務(wù)module中的TestActivity
ARouter.getInstance().build("/service/test").navigation();
image.png
//生成Group對(duì)應(yīng)的代碼（loadInto功能主要是在ARouter.init()時(shí)把Group放到group集合中）
public class ARouter$$Root$$service_module implements IRouteRoot {
@Override
public void loadInto(Map<String, Class<? extends IRouteGroup>> routes) {
routes.put("service", ARouter$$Group$$service.class);
}
}
//生成Group對(duì)應(yīng)所有子節(jié)點(diǎn)的代碼（loadInto功能主要是在APP第一次調(diào)用該group下的子節(jié)點(diǎn)時(shí)把所有的子節(jié)點(diǎn)加進(jìn)集合中）
public class ARouter$$Group$$service implements IRouteGroup {
@Override
public void loadInto(Map<String, RouteMeta> atlas) {
atlas.put("/service/fragmentService", RouteMeta.build(RouteType.FRAGMENT, FragmentService.class, "/service/fragmentservice", "service", null, -1, -2147483648));
atlas.put("/service/test", RouteMeta.build(RouteType.ACTIVITY, TestActivity.class, "/service/test", "service", null, -1, -2147483648));
}
}
上面代碼為程序編譯時(shí)生成吟榴，在APP運(yùn)行期間使用ARouter.init(Context);會(huì)調(diào)用如下代碼
//_ARouter中init方法
protected static synchronized boolean init(Application application) {
mContext = application;
LogisticsCenter.init(mContext, executor);
logger.info(Consts.TAG, "ARouter init success!");
hasInit = true;
return true;
}
//LogisticsCenter精簡(jiǎn)版
public synchronized static void init(Context context, ThreadPoolExecutor tpe) throws HandlerException {
for (String className : routerMap) {
if (className.startsWith(ROUTE_ROOT_PAKCAGE + DOT + SDK_NAME + SEPARATOR + SUFFIX_ROOT)) {
((IRouteRoot) (Class.forName(className).getConstructor().newInstance())).loadInto(Warehouse.groupsIndex);
} else if (className.startsWith(ROUTE_ROOT_PAKCAGE + DOT + SDK_NAME + SEPARATOR + SUFFIX_INTERCEPTORS)) {
((IInterceptorGroup) (Class.forName(className).getConstructor().newInstance())).loadInto(Warehouse.interceptorsIndex);
} else if (className.startsWith(ROUTE_ROOT_PAKCAGE + DOT + SDK_NAME + SEPARATOR + SUFFIX_PROVIDERS)) {
((IProviderGroup) (Class.forName(className).getConstructor().newInstance())).loadInto(Warehouse.providersIndex);
}
}
}
}
通過反射把生成的文件全限定名取到加入routermap中然后通過反射實(shí)例化對(duì)應(yīng)的類調(diào)用loadinto方法將group添加進(jìn)如下集合之中
//Warehouse 精簡(jiǎn)源碼
class Warehouse {
// group節(jié)點(diǎn)集合
static Map<String, Class<? extends IRouteGroup>> groupsIndex = new HashMap<>();
// group下子節(jié)點(diǎn)集合
static Map<String, RouteMeta> routes = new HashMap<>();
}
init完畢之后ARouter只把group節(jié)點(diǎn)初始化了
在APP調(diào)用ARouter.getInstance().build("/service/test").navigation();方法會(huì)調(diào)用如下源碼
//_ARouter 中navigation()方法精簡(jiǎn)版
final class _ARouter {
protected 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);
}
// Navigation in main looper.
new Handler(Looper.getMainLooper()).post(new Runnable() {
@Override
public void run() {
if (requestCode > 0) { // Need start for result
ActivityCompat.startActivityForResult((Activity) currentContext, intent, requestCode, postcard.getOptionsBundle());
} else {
ActivityCompat.startActivity(currentContext, intent, postcard.getOptionsBundle());
}
if ((0 != postcard.getEnterAnim() || 0 != postcard.getExitAnim()) && currentContext instanceof Activity) { // Old version.
((Activity) currentContext).overridePendingTransition(postcard.getEnterAnim(), postcard.getExitAnim());
}
if (null != callback) { // Navigation over.
callback.onArrival(postcard);
}
}
});
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;
}
}
在這里會(huì)把傳入路徑中的group解析出來查詢對(duì)應(yīng)的group下子節(jié)點(diǎn)是否已經(jīng)被加到集合中兜看，如果沒有加入則通過loadinto加入，然后通過RouteMeta中的屬性得到具體頁面的類型和class名 進(jìn)入_ARouter ._navigation()就獲得了具體的Activity 其中Fragment需要根據(jù)全限定名反射得到實(shí)例细移，此時(shí)整個(gè)流程結(jié)束
