retrofit - No se puede crear el adaptador de llamadas para io.reactivex.Observable

rx-java retrofit2

Question

Enviaré un método get simple a mi servidor (es la aplicación Rails) y obtendré el resultado usando RxJava y Retrofit. Lo que hice es:

Mi interfaz:

public interface ApiCall {
String SERVICE_ENDPOINT = "https://198.50.214.15";
@GET("/api/post")
io.reactivex.Observable<Post> getPost();
}

Mi modelo es este:

public class Post
{
@SerializedName("id")
private String id;
@SerializedName("body")
private String body;
@SerializedName("title")
private String title;
public String getId ()
{
return id;
}
public String getBody ()
{
return body;
}
public String getTitle ()
{
return title;
}
}

Y esto es lo que hice en mi actividad:

public class Javax extends AppCompatActivity {
RecyclerView rvListContainer;
postAdapter postAdapter;
List<String> messageList=new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_javax);
rvListContainer=(RecyclerView)findViewById(R.id.recyclerView);
postAdapter=new postAdapter(messageList);
rvListContainer.setAdapter(postAdapter);
}
@Override
protected void onResume() {
super.onResume();
Retrofit retrofit=new Retrofit.Builder()
.addCallAdapterFactory(RxJavaCallAdapterFactory.create())
.addConverterFactory(GsonConverterFactory.create())
.baseUrl("https://198.50.214.15")
.build();
ApiCall apiService=retrofit.create(ApiCall.class);
Observable<Post> observable=apiService.getPost();
observable.subscribeOn(Schedulers.newThread())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(responseData -> {
messageList.add(responseData.getTitle());
postAdapter.notifyDataSetChanged();
});
}
}

No sé por qué recibo este error que dice que tengo un problema con el adaptador. También incluí el adaptador en el gradle:

E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.hussein.sqlitedatabase, PID: 19445
java.lang.RuntimeException: Unable to resume activity {com.example.hussein.sqlitedatabase/com.example.hussein.sqlitedatabase.Javax}: java.lang.IllegalArgumentException: Unable to create call adapter for io.reactivex.Observable<com.example.hussein.sqlitedatabase.Post>
for method ApiCall.getPost
at android.app.ActivityThread.performResumeActivity(ActivityThread.java:2964)
at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:2993)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2395)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1321)
at android.os.Handler.dispatchMessage(Handler.java:110)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:5292)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:824)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:640)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.IllegalArgumentException: Unable to create call adapter for io.reactivex.Observable<com.example.hussein.sqlitedatabase.Post>
for method ApiCall.getPost
at retrofit2.ServiceMethod$Builder.methodError(ServiceMethod.java:751)
at retrofit2.ServiceMethod$Builder.createCallAdapter(ServiceMethod.java:236)
at retrofit2.ServiceMethod$Builder.build(ServiceMethod.java:161)
at retrofit2.Retrofit.loadServiceMethod(Retrofit.java:169)
at retrofit2.Retrofit$1.invoke(Retrofit.java:146)
at $Proxy0.getPost(Native Method)
at com.example.hussein.sqlitedatabase.Javax.onResume(Javax.java:42)
at android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1197)
at android.app.Activity.performResume(Activity.java:5343)
at android.app.ActivityThread.performResumeActivity(ActivityThread.java:2950)
... 12 more
Caused by: java.lang.IllegalArgumentException: Could not locate call adapter for io.reactivex.Observable<com.example.hussein.sqlitedatabase.Post>.
Tried:
* retrofit2.adapter.rxjava.RxJavaCallAdapterFactory
* retrofit2.ExecutorCallAdapterFactory
at retrofit2.Retrofit.nextCallAdapter(Retrofit.java:240)
at retrofit2.Retrofit.callAdapter(Retrofit.java:204)
at retrofit2.ServiceMethod$Builder.createCallAdapter(ServiceMethod.java:234)
... 20 more

Esta es mi dependencia de Gradle:

dependencies {
compile fileTree(dir: ''libs'', include: [''*.jar''])
androidTestCompile(''com.android.support.test.espresso:espresso-core:2.2.2'', {
exclude group: ''com.android.support'', module: ''support-annotations''
})
compile ''com.android.support.constraint:constraint-layout:1.0.2''
compile ''com.android.support:appcompat-v7:25.3.1''
testCompile ''junit:junit:4.12''
compile ''com.squareup.retrofit2:retrofit:2.2.0''
compile ''com.android.support:recyclerview-v7:25.3.1''
compile ''com.android.support:design:25.3.1''
compile ''io.reactivex.rxjava2:rxandroid:2.0.1''
compile ''io.reactivex.rxjava2:rxjava:2.0.1''
compile ''com.jakewharton.retrofit:retrofit2-rxjava2-adapter:1.0.0''
compile ''com.squareup.retrofit2:adapter-rxjava:2.0.2''
compile ''com.squareup.retrofit2:converter-gson:2.0.0''
compile ''com.google.code.gson:gson:2.4''
}

Answer 1

Debe decirle a Retrofit que desea usar RxJava 2, usando:

addCallAdapterFactory(RxJava2CallAdapterFactory.create())

Entonces, para crear su objeto Retrofit , tendrá algo como:

Retrofit retrofit = new Retrofit.Builder()
.baseUrl(SERVICE_ENDPOINT)
.addCallAdapterFactory(RxJava2CallAdapterFactory.create())
.build();

Answer 2

El problema es con la biblioteca que se está utilizando.

Tengo reemplaza

implementation ''com.squareup.retrofit2:adapter-rxjava:2.4.0''

con

implementation ''com.squareup.retrofit2:adapter-rxjava2:2.4.0''

y usado

Retrofit retrofit = new Retrofit.Builder()
.baseUrl(BASE_URL).client(client)
.addConverterFactory(GsonConverterFactory.create(gson))
.addCallAdapterFactory(RxJava2CallAdapterFactory.create())
.build();

Answer 3

Me encontré con el mismo problema. En lugar de agregar nuevos repositorios, puede agregar la dependencia de la biblioteca de Jake Wharton:

implementation ''com.jakewharton.retrofit:retrofit2-rxjava2-adapter:1.0.0''

Entonces puedes agregar fábrica:

Retrofit retrofit = new Retrofit.Builder()
.baseUrl("https://api.example.com")
.addCallAdapterFactory(RxJava2CallAdapterFactory.create())
.build();

El hecho de que el adaptador tenga la versión 2 ... no significa que esté diseñado para usarse con RxJava 2, como pensé.

implementation ''com.squareup.retrofit2:adapter-rxjava:2.1.0''