RxAndroid和Retrofit:无法为io.reactivex.Observable创建调用适配器<retrofit2.Response <okhttp3.ResponseBody >>

Question

我正在尝试使用rxJava,rxAndroid,Retrofit2和OkHTTP3从URL端点下载文件.我的代码无法为"Observable <retrofit2.Response <okhttp3.ResponseBody >>"创建调用适配器.这些方法对我来说都是新的,所以我相信我在这里错过了一个重要的概念.非常感谢任何方向或点.

致命异常:主要过程:com.example.khe11e.rxdownloadfile,PID:14130 java.lang.IllegalArgumentException异常:无法创建在retrofit2.ServiceMethod $ Builder.methodError方法RetrofitInterface.downloadFileByUrlRx为io.reactivex.Observable呼叫适配器>(ServiceMethod的.java:720)在retrofit2.ServiceMethod $ Builder.createCallAdapter(ServiceMethod.java:234)在retrofit2.ServiceMethod $ Builder.build(ServiceMethod.java:160)在retrofit2.Retrofit.loadServiceMethod(Retrofit.java:166)在retrofit2 .Retrofit $ 1.invoke(Retrofit.java:145)在java.lang.reflect.Proxy.invoke(Proxy.java:393)在$ Proxy0.downloadFileByUrlRx(来源不明)在com.example.khe11e.rxdownloadfile.MainActivity.downloadImage (MainActivity.java:46)在com.example.khe11e.rxdownloadfile.MainActivity $ 1.onClick(MainActivity.java:39)在android.view.View.performClick(View.java:5207)在android.view.View $ PerformClick .run(View.java:21168)在android.os.Handler.dispatchMe的android.os.Handler.handleCallback(Handler.java:746)ssage(Handler.java:95)在android.app.Looper.loop(Looper.java:148)的android.app.ActivityThread.main(ActivityThread.java:5491)at java.lang.reflect.Method.invoke(Native java.lang.IllegalArgumentException异常:方法)在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:728)在com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)所致:找不到io.reactivex.Observable>的调用适配器.尝试:*retrofit2.adapter.rxjava.RxJavaCallAdapterFactory*retrofit2.ExecutorCallAdapterFactory在retrofit2.Retrofit.nextCallAdapter(Retrofit.java:237)在retrofit2.Retrofit.callAdapter(Retrofit.java:201)在retrofit2.ServiceMethod $ Builder.createCallAdapter(ServiceMethod .java:232)......还有16个

的build.gradle:

compile 'io.reactivex.rxjava2:rxandroid:2.0.1'
compile 'io.reactivex.rxjava2:rxjava:2.0.4'
compile 'com.squareup.retrofit2:retrofit:2.1.0'
compile 'com.squareup.retrofit2:adapter-rxjava:2.1.0'

RetrofitInterface.java:

package com.example.khe11e.rxdownloadfile;
import io.reactivex.Observable;
import okhttp3.ResponseBody;
import retrofit2.Call;
import retrofit2.Response;
import retrofit2.http.GET;
import retrofit2.http.Streaming;
import retrofit2.http.Url;

public interface RetrofitInterface {
    // Retrofit 2 GET request for rxjava
    @Streaming
    @GET
    Observable<Response<ResponseBody>> downloadFileByUrlRx(@Url String fileUrl);
}

MainActivity.java:

package com.example.khe11e.rxdownloadfile;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import java.io.File;
import io.reactivex.Observable;
import io.reactivex.ObservableEmitter;
import io.reactivex.ObservableOnSubscribe;
import io.reactivex.Observer;
import io.reactivex.android.schedulers.AndroidSchedulers;
import io.reactivex.disposables.Disposable;
import io.reactivex.functions.Function;
import io.reactivex.schedulers.Schedulers;
import okhttp3.OkHttpClient;
import okhttp3.ResponseBody;
import okio.BufferedSink;
import okio.Okio;
import retrofit2.Response;
import retrofit2.Retrofit;
import retrofit2.adapter.rxjava.RxJavaCallAdapterFactory;

public class MainActivity extends AppCompatActivity {

Button downloadImgBtn;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    downloadImgBtn = (Button) findViewById(R.id.downloadImgBtn);
    downloadImgBtn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            downloadImage();
        }
    });
}

public void downloadImage(){
    RetrofitInterface downloadService = createService(RetrofitInterface.class, "https://www.nasa.gov/");
    downloadService.downloadFileByUrlRx("sites/default/files/iss_1.jpg")
            .flatMap(processResponse())
            .subscribeOn(Schedulers.io())
            .observeOn(AndroidSchedulers.mainThread())
            .subscribe(handleResult());
}

public <T> T createService(Class<T> serviceClass, String baseUrl){
    Retrofit retrofit = new Retrofit.Builder()
            .baseUrl(baseUrl)
            .client(new OkHttpClient.Builder().build())
            .addCallAdapterFactory(RxJavaCallAdapterFactory.create()).build();
    return retrofit.create(serviceClass);
}

public Function<Response<ResponseBody>, Observable<File>> processResponse(){
    return new Function<Response<ResponseBody>, Observable<File>>() {
        @Override
        public Observable<File> apply(Response<ResponseBody> responseBodyResponse) throws Exception {
            return saveToDiskRx(responseBodyResponse);
        }
    };
}

private Observable<File> saveToDiskRx(final Response<ResponseBody> response){
    return Observable.create(new ObservableOnSubscribe<File>() {
        @Override
        public void subscribe(ObservableEmitter<File> subscriber) throws Exception {
            String header = response.headers().get("Content-Disposition");
            String filename = header.replace("attachment; filename=", "");
            new File("/data/data/" + getPackageName() + "/images").mkdir();
            File destinationFile = new File("/data/data/" + getPackageName() + "/images/" + filename);

            BufferedSink bufferedSink = Okio.buffer(Okio.sink(destinationFile));
            bufferedSink.writeAll(response.body().source());
            bufferedSink.close();

            subscriber.onNext(destinationFile);
            subscriber.onComplete();
        }
    });
}

private Observer<File> handleResult(){
    return new Observer<File>() {
        @Override
        public void onSubscribe(Disposable d) {
            Log.d("OnSubscribe", "OnSubscribe");
        }

        @Override
        public void onNext(File file) {
            Log.d("OnNext", "File downloaded to " + file.getAbsolutePath());
        }

        @Override
        public void onError(Throwable e) {
            e.printStackTrace();
            Log.d("Error", "Error " + e.getMessage());
        }

        @Override
        public void onComplete() {
            Log.d("OnComplete", "onCompleted");
        }
    };
}
}

我试过添加这里提到的Call,所以它看起来像:

Call<Observable<Response<ResponseBody>>> downloadFileByUrlRx(@Url String fileUrl);

但这会导致flatMap函数出现问题,因为它无法找到符号方法flatMap(函数<Response <ResponseBody>,Observable <File >>).

Answer 1

您正在使用RxJava 1适配器进行Retrofit,将其替换为RxJava 2变体:

//compile 'com.squareup.retrofit2:adapter-rxjava:2.1.0'
compile 'com.jakewharton.retrofit:retrofit2-rxjava2-adapter:1.0.0'

UPDATE

从Retrofit版本开始,2.2.0有一个用于RxJava2的第一方调用适配器:

compile 'com.squareup.retrofit2:retrofit:2.2.0'
compile 'com.squareup.retrofit2:adapter-rxjava2:2.2.0'

Answer 2

对于新来者(2017年7月):

你肯定弄乱了你的库版本.

我一直在使用最新版本的RXAndroid 2.0.1

compile 'io.reactivex.rxjava2:rxandroid:2.1.1'
compile 'io.reactivex.rxjava2:rxjava:2.2.10'
compile 'com.squareup.retrofit2:retrofit:2.6.0'
compile 'com.squareup.retrofit2:adapter-rxjava2:2.6.0'

1)确保您有相同的Retrofit和Retrofit-RxJava适配器.

2)使用编译

------------------------------------------

不

compile 'io.reactivex.rxjava2:rxandroid:2.0.1'
compile 'io.reactivex.rxjava2:rxjava:2.1.0'
compile 'com.squareup.retrofit2:retrofit:2.3.0'
compile 'com.squareup.retrofit2:adapter-rxjava2:2.3.0'

而RxJava2CallAdapterFactory.create()不是RxJavaCallAdapterFactory.create()在建造改造时使用.

更新:2017年11月

Rxjava版本更新为2.1.5

compile 'com.squareup.retrofit2:adapter-rxjava2:2.3.0'