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kotlinlang

Does anyone know how fragments work in jetpack compose?  the documentation has a bunch of holes in its examples <https://developer.android.com/jetpack/compose/interop/interop-apis#compose-in-fragments>.

```class ExampleFragment : Fragment() {

    private var _binding: FragmentExampleBinding? = null
    // This property is only valid between onCreateView and onDestroyView.
    private val binding get() = _binding!!

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View {
        _binding = FragmentExampleBinding.inflate(inflater, container, false)
        val view = binding.root
        view.composeView.apply {
            // Dispose the Composition when viewLifecycleOwner is destroyed
            setViewCompositionStrategy(
                DisposeOnLifecycleDestroyed(viewLifecycleOwner)
            )
            setContent {
                // In Compose world
                MaterialTheme {
                    Text("Hello Compose!")
                }
            }
        }
        return view
    }

    override fun onDestroyView() {
        super.onDestroyView()
        _binding = null
    }
}```
Like where does FragmentExampleBinding?  How does the xml
```&lt;?xml version="1.0" encoding="utf-8"?&gt;
&lt;LinearLayout
    xmlns:android="<http://schemas.android.com/apk/res/android>"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"&gt;

    &lt;TextView
        android:id="@+id/hello_world"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Hello Android!" /&gt;

    &lt;androidx.compose.ui.platform.ComposeView
        android:id="@+id/compose_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent" /&gt;

&lt;/LinearLayout&gt;```
get into the above code?  I see no reference to any of the id's yet

interop-hellos.png

Some how it picks up the "Hello Android!" with out referencing it?

The example uses View Binding: <https://developer.android.com/topic/libraries/view-binding>

Which transforms `fragment_example.xml` into `FragmentExampleBinding` - an object that has a field for each view with an id - that's why there's a `view.composeView` field

So `view.composeView` is really just a super smart, cached version of `view.findViewById&lt;ComposeView&gt;(R.id.compose_view)` that is generated for you

I think that example is slightly off though - the `composeView` field is on `binding`, not on `binding.root` (that's just a normal View, not the smart binding object)