内部类上的Android数据绑定不更新TextView

public class MainActivity extends AppCompatActivity {
    // 外部类的成员变量

    public static class InnerClass {
        // 内部类的成员变量
    }
}

public class MainActivity extends AppCompatActivity {
    public static class InnerClass {
        public ObservableField<String> text = new ObservableField<>();
    }
}

<TextView
    android:text="@{innerClass.text.get()}"
    ... />

public class MainActivity extends AppCompatActivity {
    public static class InnerClass {
        public MutableLiveData<String> text = new MutableLiveData<>();

        public void updateText(String newText) {
            text.setValue(newText);
        }
    }
}

<TextView
    android:text="@{innerClass.text}"
    ... />