解决java.lang.IllegalArgumentException: Unable to create call adapter for io.reactivex.Observable问题

使用Retrofit2结合RxJava2的网络请求方式，请求的时候报如下错误，原因是adapter-rxjava包引用错了，由于用的RxJava2，所以用的依赖的adapter库也应该是RxJava2的，报错的原因就是依赖城RxJava1的adapter了

06-01 16:20:12.373 25257-25257/com.him.hisapp E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.him.hisapp, PID: 25257
    java.lang.IllegalArgumentException: Unable to create call adapter for io.reactivex.Observable<com.him.hisapp.http.Resp.RespBase<java.util.List<com.him.hisapp.http.Resp.Account>>>
        for method HttpService.login2
        at retrofit2.Utils.methodError(Utils.java:52)
        at retrofit2.HttpServiceMethod.createCallAdapter(HttpServiceMethod.java:60)
        at retrofit2.HttpServiceMethod.parseAnnotations(HttpServiceMethod.java:34)
        at retrofit2.ServiceMethod.parseAnnotations(ServiceMethod.java:36)
        at retrofit2.Retrofit.loadServiceMethod(Retrofit.java:168)
        at retrofit2.Retrofit$1.invoke(Retrofit.java:147)
        at java.lang.reflect.Proxy.invoke(Proxy.java:397)
        at $Proxy0.login2(Unknown Source)
        at com.him.hisapp.http.HttpServiceImpl.login2(HttpServiceImpl.java:147)
        at com.him.hisapp.MainActivity.login(MainActivity.java:31)
        at com.him.hisapp.MainActivity.access$000(MainActivity.java:15)
        at com.him.hisapp.MainActivity$1.onClick(MainActivity.java:25)
        at android.view.View.performClick(View.java:4785)
        at android.view.View$PerformClick.run(View.java:19888)
        at android.os.Handler.handleCallback(Handler.java:739)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:135)
        at android.app.ActivityThread.main(ActivityThread.java:5276)
        at java.lang.reflect.Method.invoke(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:372)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:911)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:706)
     Caused by: java.lang.IllegalArgumentException: Could not locate call adapter for io.reactivex.Observable<com.him.hisapp.http.Resp.RespBase<java.util.List<com.him.hisapp.http.Resp.Account>>>.
      Tried:
       * retrofit2.adapter.rxjava.RxJavaCallAdapterFactory
       * retrofit2.ExecutorCallAdapterFactory
        at retrofit2.Retrofit.nextCallAdapter(Retrofit.java:239)
        at retrofit2.Retrofit.callAdapter(Retrofit.java:203)
        at retrofit2.HttpServiceMethod.createCallAdapter(HttpServiceMethod.java:58)
        	... 20 more

错误的写法

dependencies {
    implementation 'com.squareup.retrofit2:adapter-rxjava:2.5.0'
}

public Retrofit getRetrofit() {
    retuan new Retrofit.Builder()
            .addConverterFactory(GsonConverterFactory.create())
            .addCallAdapterFactory(RxJavaCallAdapterFactory.create())
            .baseUrl(getBaseUrl())
            .build();
}

正确的写法

dependencies {
    // 改成adapter-rxjava2
    implementation 'com.squareup.retrofit2:adapter-rxjava2:2.5.0'
}

public Retrofit getRetrofit() {
    retuan new Retrofit.Builder()
            .addConverterFactory(GsonConverterFactory.create())
            // 改成RxJava2CallAdapterFactory
            .addCallAdapterFactory(RxJava2CallAdapterFactory.create())
            .baseUrl(getBaseUrl())
            .build();
}

总结

• 依赖com.squareup.retrofit2:adapter-rxjava:2.5.0改成com.squareup.retrofit2:adapter-rxjava2:2.5.0
• adapter RxJavaCallAdapterFactory改成RxJava2CallAdapterFactory