mapper函数返回null值

Question

我为调试和发布设置了相同的构建类型,

buildTypes {
    debug {
        buildConfigField "String", "API_BASE_URL", "\"https://www.testUrl.com/api/\""
        minifyEnabled true
        shrinkResources true
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        signingConfig signingConfigs.release_key
    }
    release {
        buildConfigField "String", "API_BASE_URL", "\"https://www.testUrl.com/api/\""
        minifyEnabled true
        shrinkResources true
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        signingConfig signingConfigs.release_key
    }
}

但是,如果我使用该版本构建,我会收到以下错误.此外,服务器响应完全相同.

W/System.err: java.lang.NullPointerException: The mapper function returned a null value.
W/System.err:     at b.a.e.b.b.a(Unknown Source)
W/System.err:     at b.a.e.e.b.bs$a.onNext(Unknown Source)
W/System.err:     at b.a.e.e.b.cm$a.onNext(Unknown Source)
W/System.err:     at retrofit2.adapter.rxjava2.BodyObservable$BodyObserver.onNext(Unknown Source)
W/System.err:     at retrofit2.adapter.rxjava2.BodyObservable$BodyObserver.onNext(Unknown Source)
W/System.err:     at retrofit2.adapter.rxjava2.CallExecuteObservable.subscribeActual(Unknown Source)
W/System.err:     at b.a.l.subscribe(Unknown Source)
W/System.err:     at retrofit2.adapter.rxjava2.BodyObservable.subscribeActual(Unknown Source)
W/System.err:     at b.a.l.subscribe(Unknown Source)
W/System.err:     at b.a.e.e.b.cm$a.a(Unknown Source)
W/System.err:     at b.a.e.e.b.cm.subscribeActual(Unknown Source)
W/System.err:     at b.a.l.subscribe(Unknown Source)
W/System.err:     at b.a.e.e.b.bs.subscribeActual(Unknown Source)
W/System.err:     at b.a.l.subscribe(Unknown Source)
W/System.err:     at b.a.e.e.b.bw.subscribeActual(Unknown Source)
W/System.err:     at b.a.l.subscribe(Unknown Source)
W/System.err:     at b.a.e.e.b.dd$b.run(Unknown Source)
W/System.err:     at b.a.s$a.run(Unknown Source)
W/System.err:     at b.a.e.g.j.run(Unknown Source)
W/System.err:     at b.a.e.g.j.call(Unknown Source)
W/System.err:     at java.util.concurrent.FutureTask.run(FutureTask.java:237)
W/System.err:     at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:272)
W/System.err:     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
W/System.err:     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
W/System.err:     at java.lang.Thread.run(Thread.java:761)

Answer 1

问题来自RxJava 2,它不允许null在流中传递值.特别是在你的情况下,你有一个mapper函数,它返回一个null异常明确指出的值.

您可以使用以下代码块重现该代码:

    Observable.just(1)
              .map(integer -> null)
              .test()
              .assertError(throwable -> 
                    "The mapper function returned a null value.".equals(throwable.getMessage()));