如何在不调用observe()的情况下从映射的LiveData的getValue()中获取非空结果?

我在用 Transformations.map LiveData 基于原稿。当 getValue null .

实时数据 不打电话 observe 在上面?

public class LiveDataTest {

    @Rule
    public TestRule rule = new InstantTaskExecutorRule();

    @Test
    public void mapTest() {
        final MutableLiveData<String> original = new MutableLiveData<>();
        final LiveData<String> mapped = Transformations.map(original, input -> "Mapped: " + input);

        System.out.println(original.getValue()); // null - OK
        System.out.println(mapped.getValue()); // null - OK

        original.setValue("Hello, World!");

        System.out.println(original.getValue());  // "Hello, World!" - OK
        System.out.println(mapped.getValue()); // null - Should be "Mapped: Hello, World!"
    }
}