In my single activity app I am trying to replace the UI that kotlinlang #compose

R Brian Amesbury

10/29/2019, 2:14 PM

In my single activity app, I am trying to replace the UI that I currently inflate with

Databinding

compose

in my fragments. I am doing this:

override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? =
    container.apply {
      this?.let {
        it.setContent {
          Text("Compose")
        }
      }
    }

It is failing with this exception:

java.lang.IllegalStateException: Views added to a FragmentContainerView must be associated with a Fragment. View androidx.ui.core.AndroidComposeView{99eebb1 VFED..... ......I. 0,0-0,0} is not associated with a Fragment.

container

that is passed in to

onCreateView

FragmentContainerView

which I am guessing is the view that is inflated in the activity to host the

NavGraph

. How can compose my UI in my fragment, and set it as the content?

Mihai Hrincescu

10/29/2019, 2:32 PM

You need to create a

ViewGroup

pass your `composable`using the extension function

setContent()

, this will add your

composable

as a child of the

ViewGroup

then return the

ViewGroup

as normal this way the fragment can add and remove the view from the hierarchy as it needs to. Also you need to set the

LayoutParams

ViewGroup

R Brian Amesbury

10/29/2019, 2:34 PM

That seem like a lot of work to get this to work in fragments, but thanks for the help, i’ll do that

I did this ans it works well, so I wrote a simple extension function to make it easy:

fun androidx.fragment.app.Fragment.setComposable(content: @Composable() () -> Unit): View? =
  context?.let {
    FrameLayout(it).apply {
      layoutParams = ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT)
      setContent(content)
    }
  }

It is consumed like this:

override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? =
    setComposable {
      Text("Compose With Extension")
    }

Thanks @Mihai Hrincescu for your suggestion!