ViewWindowInsetObserver

class ViewWindowInsetObserver(view: View)

This class sets up the necessary listeners on the given view to be able to observe WindowInsetsCompat instances dispatched by the system.

This class is useful for when you prefer to handle the ownership of the WindowInsets yourself. One example of this is if you find yourself using ProvideWindowInsets in fragments.

It is convenient to use ProvideWindowInsets in fragments, but that can result in a delay in the initial inset update, which results in a visual flicker. See this issue for more information.

The alternative is for fragments to manage the WindowInsets themselves, like so:

override fun onCreateView(
    inflater: LayoutInflater,
    container: ViewGroup?,
    savedInstanceState: Bundle?
): View = ComposeView(requireContext()).apply {
    layoutParams = LayoutParams(MATCH_PARENT, MATCH_PARENT)

    // Create an ViewWindowInsetObserver using this view
    val observer = ViewWindowInsetObserver(this)

    // Call start() to start listening now.
    // The WindowInsets instance is returned to us.
    val windowInsets = observer.start()

    setContent {
        // Instead of calling ProvideWindowInsets, we use CompositionLocalProvider to provide
        // the WindowInsets instance from above to LocalWindowInsets
        CompositionLocalProvider(LocalWindowInsets provides windowInsets) {
            /* Content */
            }
        }
    }

Parameters

view

The view to observe WindowInsetsCompats from.

Constructors

ViewWindowInsetObserver

fun ViewWindowInsetObserver(view: View)

The view to observe WindowInsetsCompats from.

Functions

start

fun start(consumeWindowInsets: Boolean = true, windowInsetsAnimationsEnabled: Boolean = true): WindowInsets

Start observing window insets from view.

stop

fun stop()

Removes any listeners from the view so that we no longer observe inset changes.

Properties

isObserving

var isObserving: Boolean = false

Whether this ViewWindowInsetObserver is currently observing.