public override bool TryCaptureView(View child, int pointerId)
{
if (mBehavior.mState == STATE_DRAGGING)
{
return(false);
}
if (mBehavior.mTouchingScrollingChild)
{
return(false);
}
if (mBehavior.mState == STATE_EXPANDED && mBehavior.mActivePointerId == pointerId)
{
View scroll;
if (mBehavior.mNestedScrollingChildRef.TryGetTarget(out scroll) &&
ViewCompat.CanScrollVertically(scroll, -1))
{
// Let the content scroll up
return(false);
}
}
View currentChild;
return(mBehavior.mViewRef != null &&
mBehavior.mViewRef.TryGetTarget(out currentChild) &&
currentChild == child);
}
/**
* Sets the state of the bottom sheet. The bottom sheet will transition to that state with
* animation.
*
* @param state One of {@link #STATE_COLLAPSED}, {@link #STATE_EXPANDED}, or
* {@link #STATE_HIDDEN}.
*/
public void setState(int state)
{
Debug.WriteLineIf(DebugTrace, $"setState {(AnchorBottomSheetState)state}");
if (state == mState)
{
return;
}
if (mViewRef == null)
{
// The view is not laid out yet; modify mState and let onLayoutChild handle it later
if (state == STATE_COLLAPSED || state == STATE_EXPANDED || state == STATE_ANCHOR ||
(mHideable && state == STATE_HIDDEN))
{
mState = state;
}
return;
}
View child;
if (!mViewRef.TryGetTarget(out child))
{
return;
}
int top;
if (state == STATE_COLLAPSED)
{
top = mMaxOffset;
View scroll;
if (mNestedScrollingChildRef.TryGetTarget(out scroll) && ViewCompat.CanScrollVertically(scroll, -1))
{
scroll.ScrollTo(0, 0);
}
}
else if (state == STATE_EXPANDED)
{
top = mMinOffset;
}
else if (state == STATE_ANCHOR)
{
top = mAnchorOffset;
}
else if (mHideable && state == STATE_HIDDEN)
{
top = mParentHeight;
}
else
{
throw new ArgumentException("Illegal state argument: " + state, nameof(state));
}
setStateInternal(STATE_SETTLING);
if (mViewDragHelper.SmoothSlideViewTo(child, child.Left, top))
{
ViewCompat.PostOnAnimation(child, this.CreateSettleRunnable(child, state));
}
}
public override bool CanChildScrollUp()
{
var listView = listFragment.ListView;
if (listView != null && listView.Visibility == ViewStates.Visible)
{
return(ViewCompat.CanScrollVertically(listView, -1));
}
return(false);
}
/**
* @return Whether it is possible for the child view of this layout to
* scroll up. Override this if the child view is a custom view.
*/
public bool canChildScrollUp()
{
// //For make it can work when my recycler view is in Gone.
// return false;
if (Build.VERSION.SdkInt < BuildVersionCodes.IceCreamSandwich)
{// 14
if (mTarget is AbsListView)
{
AbsListView absListView = (AbsListView)mTarget;
return(absListView.ChildCount > 0 &&
(absListView.FirstVisiblePosition > 0 || absListView.GetChildAt(0)
.Top < absListView.PaddingTop));
}
else
{
return(ViewCompat.CanScrollVertically(mTarget, -1) || mTarget.ScrollY > 0);
}
}
else
{
return(ViewCompat.CanScrollVertically(mTarget, -1));
}
}
/**
* Utility method to check whether a {@link ListView} can scroll up from it's current position.
* Handles platform version differences, providing backwards compatible functionality where
* needed.
*/
private static bool CanListViewScrollUp(ListView listView)
{
return(ViewCompat.CanScrollVertically(listView, -1));
}
// The current SwipeRefreshLayout only check its immediate child scrollability.
// In our case, ListFragment uses a ListView inside a parent FrameLayout which breaks this.
public override bool CanChildScrollUp()
{
return(GetChildrenRecursively(GetChildAt(0)).Any(v => ViewCompat.CanScrollVertically(v, -1)));
}
public override void OnNestedPreScroll(
CoordinatorLayout coordinatorLayout,
Java.Lang.Object childObject,
View target,
int dx,
int dy,
int[] consumed)
{
Debug.WriteLineIf(DebugTrace, $"OnNestedPreScroll");
View child = Android.Runtime.Extensions.JavaCast <View>(childObject);
View scrollingChild;
mNestedScrollingChildRef.TryGetTarget(out scrollingChild);
if (target != scrollingChild)
{
return;
}
int currentTop = child.Top;
int newTop = currentTop - dy;
Debug.WriteLineIf(DebugTrace, $"currentTop:{currentTop} newTop:{newTop}");
if (dy > 0)
{ // Upward
Debug.WriteLineIf(DebugTrace, $"dy > 0: Upward");
if (newTop < mMinOffset)
{
Debug.WriteLineIf(DebugTrace, $"newTop < mMinOffset: STATE_EXPANDED");
consumed[1] = currentTop - mMinOffset;
ViewCompat.OffsetTopAndBottom(child, -consumed[1]);
setStateInternal(STATE_EXPANDED);
}
else
{
Debug.WriteLineIf(DebugTrace, $"else: STATE_DRAGGING");
consumed[1] = dy;
ViewCompat.OffsetTopAndBottom(child, -dy);
setStateInternal(STATE_DRAGGING);
}
}
else if (dy < 0)
{
// Downward
Debug.WriteLineIf(DebugTrace, $"dy < 0: Downward");
if (!ViewCompat.CanScrollVertically(target, -1))
{
if (newTop <= mMaxOffset || mHideable)
{
Debug.WriteLineIf(DebugTrace, $"newTop <= mMaxOffset || mHideable: STATE_DRAGGING");
consumed[1] = dy;
ViewCompat.OffsetTopAndBottom(child, -dy);
setStateInternal(STATE_DRAGGING);
}
else
{
Debug.WriteLineIf(DebugTrace, $"else: STATE_COLLAPSED");
consumed[1] = currentTop - mMaxOffset;
ViewCompat.OffsetTopAndBottom(child, -consumed[1]);
setStateInternal(STATE_COLLAPSED);
}
}
}
dispatchOnSlide(child.Top);
mLastNestedScrollDy = dy;
mNestedScrolled = true;
}
public override void OnNestedPreScroll(CoordinatorLayout coordinatorLayout, Java.Lang.Object cChild, View target, int dx, int dy, int[] consumed, int type)
{
var child = cChild.JavaCast <View>();
_nestedScrollingChildRef.TryGetTarget(out View scrollingChild);
if (target != scrollingChild)
{
return;
}
_scrollVelocityTracker.RecordScroll(dy);
int currentTop = child.Top;
int newTop = currentTop - dy;
// Force stop at the anchor - do not go from collapsed to expanded in one scroll
if ((_lastStableState == StateCollapsed && newTop < AnchorPoint) ||
(_lastStableState == StateExpanded && newTop > AnchorPoint))
{
consumed[1] = dy;
ViewCompat.OffsetTopAndBottom(child, AnchorPoint - currentTop);
DispatchOnSlide(child.Top);
_nestedScrolled = true;
return;
}
if (dy > 0)
{ // Upward
if (newTop < _minOffset)
{
consumed[1] = currentTop - _minOffset;
ViewCompat.OffsetTopAndBottom(child, -consumed[1]);
SetStateInternal(StateExpanded);
}
else
{
consumed[1] = dy;
ViewCompat.OffsetTopAndBottom(child, -dy);
SetStateInternal(StateDragging);
}
}
else if (dy < 0)
{ // Downward
if (!ViewCompat.CanScrollVertically(target, -1))
{
if (newTop <= _maxOffset || Hideable)
{
// Restrict STATE_COLLAPSED if restrictedState is set
if (Collapsible == true || (Collapsible == false && (AnchorPoint - newTop) >= 0))
{
consumed[1] = dy;
ViewCompat.OffsetTopAndBottom(child, -dy);
SetStateInternal(StateDragging);
}
}
else
{
consumed[1] = currentTop - _maxOffset;
ViewCompat.OffsetTopAndBottom(child, -consumed[1]);
SetStateInternal(StateCollapsed);
}
}
}
DispatchOnSlide(child.Top);
_nestedScrolled = true;
}
