我們先從Retrofit的普通調用看起
BaseNetEngine.getInstance().getsApiService(ApiInterface.class) //1
.mPutCommunityBind(thirdID) //2
.compose(bindToLifecycle()) //3
.compose(RxSchedulersHelper.io_main()) //4
.subscribe(deviceBindBean -> { //5
網絡調用返回......
}, throwable -> {
......
});
上面是普通的調用,我們一行行的來分析.
開頭註釋的第一行代碼分析
ApiInterface.class 這個是一個接口,裏面定義了我們請求的方法, 如下
public interface ApiInterface {
@PUT(URLManager.PUT_COMMUNITY_BIND+"{id}")
Flowable<DeviceBindBean> mPutCommunityBind(@Path("id") String id);
}
上面定義了一個接口方法。
BaseNetEngine.getInstance() 是一個單例類,然後 getsApiService方法如下
public synchronized <T> T getsApiService(Class<T> clazz) {
T obj = (T) hashMap.get(clazz.getName());
if (obj == null) {
obj = getRetrofit().create(clazz);
hashMap.put(clazz.getName(), obj);
}
return obj;
}
接着看一下getRetrofit()方法
public Retrofit getRetrofit() {
if (sOkHttpClient == null) {
initOkHttp();
}
if (sRetrofit == null) {
ExtensionRegistry registry = ExtensionRegistry.newInstance();
sRetrofit = new Retrofit.Builder()
.baseUrl(BuildConfig.urlMAPI)
.client(sOkHttpClient)
.addConverterFactory(new NullOnEmptyConverterFactory())
.addConverterFactory(ProtoConverterFactory.createWithRegistry(registry))//一定要在gsonconvert
.addConverterFactory(GsonConverterFactory.create())
.addCallAdapterFactory(RxJava2CallAdapterFactory.create())
.build();
}
return sRetrofit;
}
該方法,先是初始化Okhttp, 然後就是addConverterFactory, 進行相關的配置。
接着看一下create()方法
public <T> T create(final Class<T> service) {
Utils.validateServiceInterface(service);
if (validateEagerly) {
eagerlyValidateMethods(service);
}
return (T) Proxy.newProxyInstance(service.getClassLoader(), new Class<?>[] { service },
new InvocationHandler() {
private final Platform platform = Platform.get();
@Override public Object invoke(Object proxy, Method method, @Nullable Object[] args)
throws Throwable {
// If the method is a method from Object then defer to normal invocation.
if (method.getDeclaringClass() == Object.class) {
return method.invoke(this, args);
}
if (platform.isDefaultMethod(method)) {
return platform.invokeDefaultMethod(method, service, proxy, args);
}
ServiceMethod<Object, Object> serviceMethod =
(ServiceMethod<Object, Object>) loadServiceMethod(method);
OkHttpCall<Object> okHttpCall = new OkHttpCall<>(serviceMethod, args);
return serviceMethod.adapt(okHttpCall);
}
});
}
create()方法返回的是一個代理類, 代理對象會調用ApiInterface.class 這個接口中的方法,當我們調用該接口裏面的方法時,其實調用的是上述InvocationHandler()裏面的invoke()方法。
開頭註釋的第二行代碼分析
第二行通過代理對象調用了mPutCommunityBind(thirdID)方法,這個方法是ApiInterface.class裏面的方法,所以會調用InvocationHandler裏面的invoke方法,所以重點來了,會調用下面的方法,然後返回的是一個observable對象
ServiceMethod<Object, Object> serviceMethod =
(ServiceMethod<Object, Object>) loadServiceMethod(method);
OkHttpCall<Object> okHttpCall = new OkHttpCall<>(serviceMethod, args);
return serviceMethod.adapt(okHttpCall);
- 首先看下 ServiceMethod, 這裏會創建ServiceMethod對象
ServiceMethod<?, ?> loadServiceMethod(Method method) {
ServiceMethod<?, ?> result = serviceMethodCache.get(method);
if (result != null) return result;
synchronized (serviceMethodCache) {
result = serviceMethodCache.get(method);
if (result == null) {
result = new ServiceMethod.Builder<>(this, method).build();
serviceMethodCache.put(method, result);
}
}
return result;
}
public ServiceMethod build() {
//這裏的callAdapter就是之前配置的RxJava2CallAdapterFactory.create()
callAdapter = createCallAdapter();
responseType = callAdapter.responseType();
......
//這裏的responseConver也是之前配置的GsonConverterFactory.create()
responseConverter = createResponseConverter();
for (Annotation annotation : methodAnnotations) {
parseMethodAnnotation(annotation);
}
......
......
return new ServiceMethod<>(this);
}
ServiceMethod 主要是處理之前Retrofit的配置,其內部解析相關注解。
- 然後接着看OkHttpCall方法。這裏面封裝了okhttp的方法,比如request,response方法
- 然後接着看serviceMethod.adapt(okHttpCall); 這裏的adapt方法是callAdapter.adapt(call); 這裏的callAdapter是RxJava2CallAdapter。所以我們進入到RxJava2CallAdapter的adapt方法看一看,如下
@Override public Object adapt(Call<R> call) {
//這裏主要根據isAsync創建同步或者異步的Observable�, 其主要作用的是爲了請求是同步還是異步
Observable<Response<R>> responseObservable = isAsync
? new CallEnqueueObservable<>(call)
: new CallExecuteObservable<>(call);
Observable<?> observable;
if (isResult) {
observable = new ResultObservable<>(responseObservable);
} else if (isBody) {
observable = new BodyObservable<>(responseObservable);
} else {
observable = responseObservable;
}
if (scheduler != null) {
observable = observable.subscribeOn(scheduler);
}
if (isFlowable) {
return observable.toFlowable(BackpressureStrategy.LATEST);
}
......
return observable;
}
所以調用第二行代碼返回CallEnqueueObservable,或者CallExecuteObservable 默認是返回CallExecuteObservable進行同步的請求
開頭註釋的第五行代碼分析
第三行,第四行主要是Rxjava相關的方法,第三行是綁定Rx生命週期,第四行是Rx的線程切換,所以我們主要看第五行。第五行主要是方法請求,這裏面會進行網絡調用。
我們進入subscribe源碼看一下
public final void subscribe(FlowableSubscriber<? super T> s) {
ObjectHelper.requireNonNull(s, "s is null");
try {
......
subscribeActual(z);
} catch (NullPointerException e) { // NOPMD
throw e;
} catch (Throwable e) {
......
}
}
這是Flowable裏面的抽象方法
protected abstract void subscribeActual(Subscriber<? super T> s);
我們知道第二步返回的對象是CallExecuteObservable, 那麼看下該對象下的subscribeActual方法,,這裏的網絡請求是同步的方法
final class CallExecuteObservable<T> extends Observable<Response<T>> {
@Override protected void subscribeActual(Observer<? super Response<T>> observer) {
// Since Call is a one-shot type, clone it for each new observer.
Call<T> call = originalCall.clone();
observer.onSubscribe(new CallDisposable(call));
boolean terminated = false;
try {
//這裏進行真正的網絡請求
Response<T> response = call.execute();
if (!call.isCanceled()) {
observer.onNext(response);
}
if (!call.isCanceled()) {
terminated = true;
observer.onComplete();
}
} catch (Throwable t) {
Exceptions.throwIfFatal(t);
if (terminated) {
RxJavaPlugins.onError(t);
} else if (!call.isCanceled()) {
try {
observer.onError(t);
} catch (Throwable inner) {
Exceptions.throwIfFatal(inner);
RxJavaPlugins.onError(new CompositeException(t, inner));
}
}
}
}
}
所以當調用第五行的時候,會進行真正的網絡請求