[BottomSheetBehavior] State is incorrect if updated during settling animation #516
Description
Description:
BottomSheetBehavior#state is not updated correctly if it was updated during the BottomSheetBehavior.SETTLING state. BottomSheetCallback$onStateChanged is not called with the correct value either.
Visually, the sheet is in the proper state.
Expected behavior:
BottomSheetBehavior#state should match its visual state and BottomSheetCallback#onStateChanged should be called with the latest state change.
Source code:
Sample project: BottomSheetDemo.zip
Snippet to reproduce bug:
class BottomSheetView @JvmOverloads constructor(context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0, defStyleRes: Int = 0) : FrameLayout(context, attrs, defStyleAttr, defStyleRes), CoordinatorLayout.AttachedBehavior {
private val bottomSheetBehavior = BottomSheetBehavior<BottomSheetView>()
init {
// Initialize sheet to be hidden and set callback for when the state changes
bottomSheetBehavior.isHideable = true
bottomSheetBehavior.setBottomSheetCallback(object : BottomSheetBehavior.BottomSheetCallback() {
override fun onSlide(p0: View, p1: Float) = Unit
override fun onStateChanged(p0: View, p1: Int) {
println("state changed $p1")
}
})
updateState(BottomSheetBehavior.STATE_HIDDEN)
}
override fun onAttachedToWindow() {
super.onAttachedToWindow()
// Update state to be expanded (from hidden)
postDelayed({
updateState(BottomSheetBehavior.STATE_EXPANDED)
// Update state to be hidden (from expanded during the settling animation)
postDelayed({
updateState(BottomSheetBehavior.STATE_HIDDEN)
// Query the state of the sheet after animation completes
postDelayed({
println("query state ${bottomSheetBehavior.state}")
}, 1000)
}, 300)
}, 3000)
}
private fun updateState(state: Int) {
println("update state to $state")
bottomSheetBehavior.state = state
}
override fun getBehavior(): CoordinatorLayout.Behavior<BottomSheetView> = bottomSheetBehavior
}On 1.1.0-alpha03 and newer versions (including 1.1.0-alpha09), the above outputs:
update state to 5
update state to 3
state changed 2
update state to 5
state changed 3
query state 3
On 1.0.0, the above outputs:
update state to 5
update state to 3
state changed 2
update state to 5
state changed 3
state changed 5
query state 5
The sheet's end state should be HIDDEN (5), but it returns EXPANDED (3).
Android API version: Reproducible on API 21 (Lollipop) and 29 (Q Beta)
Material Library version: 1.1.0-alpha09
Device: Nexus 5X emulator and Pixel 3