public override bool OnLayoutChild(CoordinatorLayout parent, Java.Lang.Object child, int layoutDirection)
{
if (!(child is NestedScrollView view))
{
return(base.OnLayoutChild(parent, child, layoutDirection));
}
// First layout the child as normal.
parent.OnLayoutChild(view, layoutDirection);
// Center the FAB vertically along the top edge of the card.
int fabHalfHeight = view.FindViewById(Resource.Id.fab).Height / 2;
SetTopMargin(view.FindViewById(Resource.Id.cardview), fabHalfHeight);
// Give the RecyclerView a maximum height to ensure the card will never
// overlap the toolbar as it scrolls.
int rvMaxHeight =
view.Height
- fabHalfHeight
- view.FindViewById(Resource.Id.card_title).Height
- view.FindViewById(Resource.Id.card_subtitle).Height;
MaxHeightRecyclerView rv = view.FindViewById <MaxHeightRecyclerView>(Resource.Id.card_recyclerview);
rv.SetMaxHeight(rvMaxHeight);
// Give the card container top padding so that only the top edge of the card
// initially appears at the bottom of the screen. The total padding will
// be the distance from the top of the screen to the FAB's top edge.
View cardContainer = view.FindViewById(Resource.Id.card_container);
int toolbarContainerHeight = parent.GetDependencies(view)[0].Height;
SetPaddingTop(cardContainer, rvMaxHeight - toolbarContainerHeight);
// Offset the child's height so that its bounds don't overlap the
// toolbar container.
ViewCompat.OffsetTopAndBottom(view, toolbarContainerHeight);
// Add the same amount of bottom padding to the RecyclerView so it doesn't
// display its content underneath the navigation bar.
SetPaddingBottom(rv, toolbarContainerHeight);
// Return true so that the parent doesn't waste time laying out the
// child again (any modifications made above will have triggered a second
// layout pass anyway).
return(true);
}
private static float GetTranslationY(CoordinatorLayout parent, Android.Views.View child)
{
var minOffset = 0.0F;
var dependencies = parent.GetDependencies(child);
var i = 0;
for (var z = dependencies.Count; i < z; ++i)
{
var view = dependencies[i];
if (IsInstanceOf <Snackbar.SnackbarLayout>(view) && parent.DoViewsOverlap(child, view))
{
minOffset = Math.Min(minOffset, ViewCompat.GetTranslationY(view) - view.Height);
}
}
return(minOffset);
}
private float GetTranslationY(CoordinatorLayout parent, View child)
{
float minOffset = 0.0F;
var dependencies = parent.GetDependencies(child);
int i = 0;
for (int z = dependencies.Count; i < z; ++i)
{
View view = (View)dependencies[i];
if (IsInstanceOf <Snackbar.SnackbarLayout>(view) && parent.DoViewsOverlap(child, view))
{
minOffset = Math.Min(minOffset, ViewCompat.GetTranslationY(view) - (float)view.Height);
}
}
return(minOffset);
}
public override void OnNestedScroll(CoordinatorLayout coordinatorLayout, Java.Lang.Object child, View target, int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed)
{
// dyconsumed: user initiates movement on the y-axis and it happens on screen
// dyunconsumed: user initiates movement on the y-axis but it doesn't happen on screen, for example, downwards movement at the bottom end of the list.
// dy > 0: user swiping up, so screen in scrolling down
// dy < 0: user swiping down, so screen is scrolling up
base.OnNestedScroll(coordinatorLayout, child, target, dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed);
BottomNavigationView childView = child.JavaCast <BottomNavigationView>();
if (dyUnconsumed > 0 || dyConsumed > 0)
{
this.SlideDown(childView);
}
else if (dyUnconsumed < 0 || dyConsumed < 0)
{
this.SlideUp(childView);
}
// define our own behavior
IList <View> dependencies = coordinatorLayout.GetDependencies(childView);
foreach (View view in dependencies)
{
if (view is FloatingActionButton)
{
FloatingActionButton floatingActionButtonView = view.JavaCast <FloatingActionButton>();
if (dyUnconsumed > 0 || dyConsumed > 0)
{
floatingActionButtonView.Hide();
}
else if (dyUnconsumed < 0 || dyConsumed < 0)
{
floatingActionButtonView.Show();
}
}
}
}