RxValue.java 文件源码

/**
 * @param query
 * @return
 */
@NonNull
@CheckReturnValue
public static Single<DataSnapshot> single(@NonNull final Query query) {
    return Single.create(new SingleOnSubscribe<DataSnapshot>() {
        @Override
        public void subscribe(
                @NonNull final SingleEmitter<DataSnapshot> emit) throws Exception {
            final ValueEventListener listener = listener(emit);

            emit.setCancellable(new Cancellable() {
                @Override
                public void cancel() throws Exception {
                    query.removeEventListener(listener);
                }
            });

            query.addListenerForSingleValueEvent(listener);
        }
    });
}