每个人都在谈论膨胀()，但如果我们想在onViewCreated()中使用它呢?

可以使用具体绑定类的bind(视图)方法获取视图的ViewDataBinding实例。

通常我们这样写BaseFragment(简化):

// BaseFragment.kt
abstract fun layoutId(): Int

override fun onCreateView(inflater, container, savedInstanceState) = 
    inflater.inflate(layoutId(), container, false)

并在子片段中使用它。

// ConcreteFragment.kt
override fun layoutId() = R.layout.fragment_concrete

override fun onViewCreated(view, savedInstanceState) {
    val binding = FragmentConcreteBinding.bind(view)
    // or
    val binding = DataBindingUtil.bind<FragmentConcreteBinding>(view)
}

如果所有fragment都使用数据绑定，您甚至可以使用类型参数使其更简单。

abstract class BaseFragment<B: ViewDataBinding> : Fragment() {
    abstract fun onViewCreated(binding: B, savedInstanceState: Bundle?)

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        onViewCreated(DataBindingUtil.bind<B>(view)!!, savedInstanceState)
    }
}

我不知道是否可以在这里断言非空，但是。你懂的。如果你想让它为空，你可以这样做。

在Android DataBinding中试试这个

FragmentMainBinding binding;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        binding = DataBindingUtil.inflate(inflater, R.layout.fragment_main, container, false);
        View rootView = binding.getRoot();
        initInstances(savedInstanceState);
        return rootView;
}

Kotlin中的另一个例子:

override fun onCreateView(inflater: LayoutInflater?, container: ViewGroup?, savedInstanceState: Bundle?): View? {
    val binding = DataBindingUtil
            .inflate< MartianDataBinding >(
                    inflater,
                    R.layout.bla,
                    container,
                    false
            )

    binding.modelName = // ..

    return binding.root
}

注意，“MartianDataBinding”的名称取决于布局文件的名称。如果文件命名为“marti_data”，那么正确的名称应该是MartianDataBinding。

科特林

         override fun onCreateView(
                 inflater: LayoutInflater, container: ViewGroup?,
                 savedInstanceState: Bundle?
            ): View? 
    { 
                 val binding = FragmentFirstBinding.inflate(inflater,container,false)      
               return  binding.root;
            

}

其中FragmentFirstBinding是由android studio使用视图绑定自动生成的。在我的代码片段名称是FirstFragment。

首先，您需要将这一行添加到构建中。Gradle(app模块)文件。

buildFeatures{
        viewBinding true
    }

在我的代码中工作。

private FragmentSampleBinding dataBiding;
private SampleListAdapter mAdapter;

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    super.onCreateView(inflater, container, savedInstanceState);
    dataBiding = DataBindingUtil.inflate(inflater, R.layout.fragment_sample, null, false);
    return mView = dataBiding.getRoot();
}

这是你在kotlin中可以做到的:

//Pass the layout as parameter to the fragment constructor    
class SecondFragment : Fragment(R.layout.fragment_second) {

    private var _binding: FragmentSecondBinding? = null
    private val binding  get() = _binding!!

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        _binding = FragmentSecondBinding.bind(view)  //if the view is already inflated then we can just bind it to view binding.

    }

    //Note: Fragments outlive their views. Make sure you clean up any references to the binding class
    // instance in the fragment's onDestroyView() method.
    override fun onDestroyView() {
        Toast.makeText(activity, "On destroy", Toast.LENGTH_SHORT).show()
        super.onDestroyView()
        _binding = null
    }
}

你可以像这样从你的布局中访问视图元素:

binding.tvName.text = "Messi"

其中tvName是视图元素的id。