is there any reason why I shouldn't use `LocalConf...

# compose

[czuckie]

is there any reason why I shouldn't use LocalConfiguration.current.screenWidthDp instead of something like the WindowMetricsCalculator as the screenWidthDp (and screenHeightDp ) values seem to update with the size of the window (and on a foldable device, it also updates as expected)?

[Louis Pullen-Freilich [G]]

Different API levels will handle cutouts / multi window / picture in picture etc differently, so this is not a consistent view of the actual window size. If you care about the size of the window your app is displayed in, you should use WindowMetricsCalculator / material3-window-size-class

https://developer.android.com/guide/topics/large-screens/support-different-screen-sizes

[Louis Pullen-Freilich [G]]

Specifically even on the latest Android versions, I think screenWidthDp will always exclude insets, whereas WindowMetricsCalculator will include that, for the total size of the window

[Alex Vanyo]

Exactly that, screenWidthDp and screenHeightDp can be smaller than the overall size of the Window with a difference that depends on the insets. WindowMetricsCalculator gives a more accurate value.

If you rotate your device 90 degrees, you'd expect that the "width" and "height" values swap. That is true for WindowMetricsCalculator, but won't necessarily be true for screenWidthDp and screenHeightDp

Another fun edge case fact related to this: it's possible to have LocalConfiguration.current.orientation return portrait, but screenWidthDp is actually larger than screenHeightDp in a situation where the aspect ratio is almost square (although that's more of another reason to avoid depending on portrait vs landscape to make large layout decisions)

[czuckie]

Thank you for this! This is the kind of insight I can't find on my own, much appreciated!

[czuckie]

Just checking then, is the use of LocalConfiguration.current here to somehow observe configuration changes as a side effect so the function will recompose?

@ExperimentalMaterial3WindowSizeClassApi
@Composable
fun calculateWindowSizeClass(activity: Activity): WindowSizeClass {
    // Observe view configuration changes and recalculate the size class on each change. We can't
    // use Activity#onConfigurationChanged as this will sometimes fail to be called on different
    // API levels, hence why this function needs to be @Composable so we can observe the
    // ComposeView's configuration changes.
    LocalConfiguration.current
    val density = LocalDensity.current
    val metrics = WindowMetricsCalculator.getOrCreate().computeCurrentWindowMetrics(activity)
    val size = with(density) { metrics.bounds.toComposeRect().size.toDpSize() }
    return WindowSizeClass.calculateFromSize(size)
}

[Louis Pullen-Freilich [G]]

Yes