不能将com.firebase.ui.firestore.paging.FirestoreDataSource转换为androidx.paging.InitialDataSource

Question

下面是我在mAdapter.startListening()上得到的内容，我从FirestorePagingAdapter扩展了我的适配器

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.valorem.flobooks.debug, PID: 14886
    java.lang.ClassCastException: androidx.paging.InitialDataSource cannot be cast to com.firebase.ui.firestore.paging.FirestoreDataSource
        at com.firebase.ui.firestore.paging.FirestorePagingAdapter$5.apply(FirestorePagingAdapter.java:98)
        at com.firebase.ui.firestore.paging.FirestorePagingAdapter$5.apply(FirestorePagingAdapter.java:95)
        at androidx.lifecycle.Transformations$2.onChanged(Transformations.java:143)
        at androidx.lifecycle.MediatorLiveData$Source.onChanged(MediatorLiveData.java:152)
        at androidx.lifecycle.LiveData.considerNotify(LiveData.java:133)
        at androidx.lifecycle.LiveData.dispatchingValue(LiveData.java:146)
        at androidx.lifecycle.LiveData$ObserverWrapper.activeStateChanged(LiveData.java:468)
        at androidx.lifecycle.LiveData.observeForever(LiveData.java:234)
        at androidx.lifecycle.MediatorLiveData$Source.plug(MediatorLiveData.java:141)
        at androidx.lifecycle.MediatorLiveData.onActive(MediatorLiveData.java:118)
        at androidx.lifecycle.LiveData.changeActiveCounter(LiveData.java:390)
        at androidx.lifecycle.LiveData$ObserverWrapper.activeStateChanged(LiveData.java:466)
        at androidx.lifecycle.LiveData.observeForever(LiveData.java:234)
        at com.firebase.ui.firestore.paging.FirestorePagingAdapter.startListening(FirestorePagingAdapter.java:181)
        at com.valorem.flobooks.helpAndSupport.CategoryQuestionsFragment.onStart(CategoryQuestionsFragment.kt:91)

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Answer 1

我通过更新我的成绩文件来解决这个问题。

一开始我只有：

dependencies {
implementation("androidx.paging:paging-runtime:2.1.2")
}

但是，我在这里添加了文档中显示的其余部分

https://developer.android.com/topic/libraries/architecture/paging

dependencies {
 implementation("androidx.paging:paging-runtime:2.1.2") 

    // alternatively - without Android dependencies for testing
    testImplementation("androidx.paging:paging-common:2.1.2") 

    // optional - RxJava support
    implementation("androidx.paging:paging-rxjava2:2.1.2")

}