You can set a default size for your app to launch using the <layout> element in your AndroidManifest. You can find more details on layout in the Android developers guide.
Multi-panel activity on Meta Horizon OS allows multiple activities to run simultaneously in separate panels, without integrating any other SDK.
private fun openNewPanelActivity() {
val intent = Intent(this, AnotherPanelActivity::class.java)
intent.addFlags(
Intent.FLAG_ACTIVITY_LAUNCH_ADJACENT
or Intent.FLAG_ACTIVITY_NEW_TASK
or Intent.FLAG_ACTIVITY_MULTIPLE_TASK
)
startActivity(intent)
}