1. 确认在Layout文件中是否设置了lifecycleOwner:

...

2. 确认Fragment中是否设置了ViewModel:

class MyFragment : Fragment() { private lateinit var binding: MyFragmentBinding private lateinit var viewModel: MyViewModel

override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
    binding = DataBindingUtil.inflate(inflater, R.layout.my_fragment, container, false)
    viewModel = ViewModelProviders.of(this).get(MyViewModel::class.java)
    binding.viewModel = viewModel
    binding.lifecycleOwner = viewLifecycleOwner // 设置lifecycleOwner
    return binding.root
}

}

3. 为LiveData和ObservableField添加更新事件:

class MyViewModel : ViewModel() { val text = MutableLiveData()

fun updateText() {
    text.value = "Hello World!"
}

}

class MyFragment : Fragment() { ... override fun onViewCreated(view: View, savedInstanceState: Bundle?) { super.onViewCreated(view, savedInstanceState) viewModel.text.observe(viewLifecycleOwner, Observer { text -> // 添加更新事件 binding.textView.text = text }) } }

4. 确认项目的Data Binding Library是否已经添加:

android { ... buildFeatures { dataBinding true // 添加dataBinding功能 } }