public void OnScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount)
{
//计算中点
centerY = Height / 2;
//判断中点的有效性
if (centerY <= 0)
{
return;
}
//开始对当前显示的View进行缩放
for (int i = 0; i < visibleItemCount; i++)
{
//获取item
View temp_view = GetChildAt(i);
//计算item的中点Y坐标
float itemY = temp_view.Bottom - (temp_view.Height / 2);
//计算离中点的距离
float distance = centerY;
if (itemY > centerY)
{
distance = itemY - centerY;
}
else
{
distance = centerY - itemY;
}
//根据距离进行缩放
temp_view.ScaleY = (1.1f - (distance / centerY) < 0 ? 0 : 1.1f - (distance / centerY));
temp_view.ScaleX = (1.1f - (distance / centerY) < 0 ? 0 : 1.1f - (distance / centerY));
//根据距离改变透明度
temp_view.Alpha = (1.1f - (distance / centerY) < 0 ? 0 : 1.1f - (distance / centerY));
}
}
public void OnScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount)
{
var wasTracked = false;
foreach (TrackElement t in _trackElements)
{
if (!wasTracked)
{
if (t.IsSafeToTrack(view))
{
wasTracked = true;
_contentOffset += t.GetDeltaY();
SendScrollEvent(_contentOffset);
t.SyncState(view);
}
else
{
t.Reset();
t.SyncState(view);
}
}
else
{
t.SyncState(view);
}
}
}
public void OnScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount)
{
if (!IsBuildingLayOut)
{
Element?.OnScrolling(this, EventArgs.Empty);
}
}
public static void MakeFlingAware(this AbsListView list)
{
list.SetOnScrollListener(new ScrollChangedListener((view, state) =>
{
(view.Adapter as IFlingAwareAdapter).FlingScrollActive = state == ScrollState.Fling;
}));
}
public void OnScrollStateChanged(AbsListView view, [GeneratedEnum] ScrollState scrollState)
{
if (scrollState == 0)
{
// stopped
}
if (processingSwipe == false)
{
processingSwipe = true;
if (lw.Id == view.Id)
{
var yPosition = GetYPosition();
int currentFirstVisibleItem = lw.FirstVisiblePosition;
if (currentFirstVisibleItem > mLastFirstVisibleItem)
{
//Down
Source.FireTopSwipe(CustomListview.Swipe.DownSwipe, yPosition, currentFirstVisibleItem);
}
else if (currentFirstVisibleItem < mLastFirstVisibleItem)
{
// Up
Source.FireTopSwipe(CustomListview.Swipe.UpSwipe, yPosition, currentFirstVisibleItem);
}
mLastFirstVisibleItem = currentFirstVisibleItem;
}
processingSwipe = false;
}
}
public void OnScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount)
{
if (CanLoad)
{
LoadData();
}
}
public void OnScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount)
{
// If the total item count is zero and the previous isn't, assume the
// list is invalidated and should be reset back to initial state
if (totalItemCount < previousTotalItemCount)
{
this.currentPage = this.startingPageIndex;
this.previousTotalItemCount = totalItemCount;
if (totalItemCount == 0)
{
this.loading = true;
}
}
// If it's still loading, we check to see if the dataset count has
// changed, if so we conclude it has finished loading and update the current page
// number and total item count.
if (loading && (totalItemCount > previousTotalItemCount))
{
loading = false;
previousTotalItemCount = totalItemCount;
currentPage++;
}
// If it isn't currently loading, we check to see if we have breached
// the visibleThreshold and need to reload more data.
// If we do need to reload some more data, we execute onLoadMore to fetch the data.
if (!loading && (firstVisibleItem + visibleItemCount + visibleThreshold) >= totalItemCount)
{
loading = onLoadMore(currentPage + 1, totalItemCount);
}
}
/// <summary>
/// Callback method to be invoked while the list view or grid view is being scrolled.
/// If the view is being scrolled, this method will be called before the next frame of the scroll is rendered.
/// In particular, it will be called before any calls to getView(int, View, ViewGroup)
/// </summary>
/// <param name="view">The view whose scroll state is being reported</param>
/// <param name="scrollState">The current scroll state. One of SCROLL_STATE_TOUCH_SCROLL or SCROLL_STATE_IDLE</param>
public void OnScrollStateChanged(AbsListView view, ScrollState scrollState)
{
if (this.BottomToolbar == null)
{
return;
}
if (scrollState == ScrollState.TouchScroll || scrollState == ScrollState.Fling)
{
this.BottomToolbar.Animate().Cancel();
this.BottomToolbar.Animate().TranslationYBy(150);
}
else
{
if (this.IsLastItemVisible && this.LastItemIsAtBottom)
{
this.BottomToolbar.Animate().Cancel();
this.BottomToolbar.Animate().TranslationYBy(150);
}
else
{
int initPosY = this.BottomToolbar.ScrollY;
this.BottomToolbar.Animate().Cancel();
this.BottomToolbar.Animate().TranslationY(initPosY);
}
}
}
/// <summary>
/// Called when the scroll has started or stopped.
/// Pass this on to all the listeners
/// </summary>
/// <param name="view"></param>
/// <param name="scrollState"></param>
public void OnScrollStateChanged(AbsListView view, [GeneratedEnum] ScrollState scrollState)
{
foreach (AbsListView.IOnScrollListener onScrollListener in listeners)
{
onScrollListener.OnScrollStateChanged(view, scrollState);
}
}
public void OnScroll(AbsListView aView, int aFirstVisibleItem, int aVisibleItemCount, int aTotalItemCount)
{
lock (iLock)
{
iVisibleScrollRange = new ScrollRange(aFirstVisibleItem, aFirstVisibleItem + aVisibleItemCount);
}
}
public void OnScrollStateChanged(AbsListView view, [GeneratedEnum] ScrollState scrollState) //called when users starts or stops scrolling, and when scolling animation stops
{
if (scrollState == ScrollState.Idle)
{
currentLastVisibleItem = ChatMessageWindow.LastVisiblePosition;
}
}
public void SetFlinging(AbsListView aListView, bool aFlinging)
{
bool stateChanged = false;
lock (iFlingingLists)
{
bool wasFlinging = iFlingingLists.Count != 0;
if (aFlinging && !iFlingingLists.Contains(aListView))
{
iFlingingLists.Add(aListView);
}
else if (!aFlinging && iFlingingLists.Contains(aListView))
{
iFlingingLists.Remove(aListView);
}
bool isFlinging = iFlingingLists.Count != 0;
if (wasFlinging && !isFlinging)
{
stateChanged = true;
}
else if (!wasFlinging && isFlinging)
{
stateChanged = true;
}
}
if (stateChanged)
{
OnEventFlingStateChanged();
}
}
protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
Xamarin.Essentials.Platform.Init(this, savedInstanceState);
// Set our view from the "main" layout resource
SetContentView(Resource.Layout.activity_main);
myListView = FindViewById <AbsListView>(Resource.Id.myListView);
items = new List <MyPerson>()
{
new MyPerson()
{
FirstName = "Pesho",
LastName = "Peshev",
Age = 20,
Gender = "MALE"
},
new MyPerson()
{
FirstName = "Gosho",
LastName = "Goshov",
Age = 18,
Gender = "MALE"
},
new MyPerson()
{
FirstName = "Tosho",
LastName = "Toshov",
Age = 25,
Gender = "MALE"
}
};
MyListViewAdapter adapter = new MyListViewAdapter(this, items);
}
void AbsListView.IOnScrollListener.OnScrollStateChanged
(
AbsListView objectListView,
[GeneratedEnum] ScrollState scrollState
)
{
}
//@Override
public void OnScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount)
{
foreach (IOnScrollListener onScrollListener in mOnScrollListeners)
{
onScrollListener.OnScroll(view, firstVisibleItem, visibleItemCount, totalItemCount);
}
}
public void OnScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount)
{
int lastVisibleItem = firstVisibleItem + visibleItemCount - 1;
Android.Views.View child = null;
if (firstVisibleItem != prevFirstVisibleItem)
{
child = super.GetChildAt(0);
}
if (prevLastVisibleItem != lastVisibleItem)
{
child = super.GetChildAt(super.ChildCount - 1);
}
if (child != null)
{
// Workaround to set newly scrolled items as valid drop targets
child.Visibility = ViewStates.Invisible;
child.Visibility = ViewStates.Visible;
}
prevLastVisibleItem = lastVisibleItem;
prevFirstVisibleItem = firstVisibleItem;
}
void AbsListView.IOnScrollListener.OnScrollStateChanged(AbsListView view, ScrollState scrollState)
{
if (scrollState == ScrollState.Idle)
{
UpdateChildrenControlPoints(0);
}
}
public void OnScrollStateChanged(AbsListView view, ScrollState scrollState)
{
if (super.isScrolling)
{
super.SmoothScrollBy(super.scrollBy, 0);
}
}
public void OnScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount)
{
if (scrollFlag)
{
if (firstVisibleItem > lastVisibleItemPosition)
{
// Slippery //Up
if (HomePage != null)
{
HomePage.ToggleFloatingActionButton = true;
}
}
else if (firstVisibleItem < lastVisibleItemPosition)
{
// Sliding //down
if (HomePage != null)
{
HomePage.ToggleFloatingActionButton = false;
}
}
else
{
return;
}
lastVisibleItemPosition = firstVisibleItem;
}
}
public void OnScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount)
{
if (view is PinnedHeaderListView)
{
((PinnedHeaderListView)view).configureHeaderView(firstVisibleItem);
}
}
public void OnScrollStateChanged(AbsListView view, ScrollState scrollState)
{
if (Control == null)
{
return;
}
if (previousState != ScrollState.Idle && scrollState == ScrollState.Idle)
{
int count = view.ChildCount - 2; // visible views count
int lastVisibleItemPosition = view.LastVisiblePosition - 2;
if (view.FirstVisiblePosition == 0 && isScrollingUp)
{
BaseControl.OnScrolledTop();
}
}
//if (scrollState == ScrollState.Idle)
if (!skipLastVisibleItem)
{
BaseControl.LastVisiblePosition = view.LastVisiblePosition - 2;
}
previousState = scrollState;
}
public void OnScrollStateChanged(AbsListView listView, ScrollState scrollState)
{
CoreUtility.ExecuteMethod("OnScrollStateChanged", delegate()
{
if (this.ViewModel != null)
{
if (this.ViewModel.HasMoreData)
{
if (listView.LastVisiblePosition >= listView.Count - 1 - this.ViewModel.ScrollThresholdCount)
{
Container.Track.LogTrace("Getting more data");
this.ViewModel.DoGetMoreData(); // it has its own built-in skip mechanism
}
}
int topRowVerticalPosition = 0;
if (this.ListView != null && this.ListView.ChildCount > 0)
{
topRowVerticalPosition = this.ListView.GetChildAt(0).Top;
}
if (this.RefreshLayout != null)
{
this.RefreshLayout.Enabled = (topRowVerticalPosition >= 0);
}
}
});
}
public static void MakeFlingAware(this AbsListView list, Action <bool> action)
{
list.SetOnScrollListener(new ScrollChangedListener((view, state) =>
{
action.Invoke(state == ScrollState.Fling);
}));
}
public void OnScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount)
{
System.Diagnostics.Debug.WriteLine(firstVisibleItem);
if (firstVisibleItem + visibleItemCount == totalItemCount) // Clear items, add from current half way to chunk size after last item, scroll back to old last item
{
var firstItem = adapter.GetItem(chunksize);
adapter.Clear();
for (int i = 0; i < chunksize * 2; i++)
{
adapter.Add(firstItem.AddDays(i));
}
adapter.NotifyDataSetChanged();
view.SetSelection(chunksize - visibleItemCount - 1);
}
else if (firstVisibleItem == 0) // Clear items, add from chunk size before first item, scroll back to old first item
{
var lastItem = adapter.GetItem(chunksize);
adapter.Clear();
for (int i = chunksize * 2 - 1; i >= 0; i--)
{
adapter.Add(lastItem.AddDays(-i));
}
adapter.NotifyDataSetChanged();
view.SetSelection(chunksize - 1);
}
}
public void OnScrollStateChanged(AbsListView view, ScrollState scrollState)
{
if (psl.mDelegateOnScrollListener != null) // delegate
{
psl.mDelegateOnScrollListener.OnScrollStateChanged(view, scrollState);
}
}
/// <summary>
/// Bind this class to the goto top button in the parent view
/// </summary>
/// <param name="parentView"></param>
/// <param name="listView"></param>
public void BindControl(View parentView, AbsListView listView)
{
if (parentView != null)
{
fab = parentView.FindViewById <FloatingActionButton>(Resource.Id.goto_top_button);
if (fab != null)
{
// Hide the button initially
fab.Visibility = ViewStates.Gone;
// Hook into the listview's scroll events
listView.SetOnScrollListener(this);
// Scroll back to the top when the button is clicked
fab.Click += (sender, e) =>
{
if (listView.FirstVisiblePosition > 20)
{
listView.SetSelection(20);
}
listView.SmoothScrollToPosition(0);
};
}
}
else
{
fab = null;
}
}
public void OnScrollStateChanged(AbsListView view, ScrollState scrollState)
{
if (OnScrollListener != null)
{
OnScrollListener.OnScrollStateChanged(view, scrollState);
}
}
public static void MakeFlingAware(this AbsListView list, Action <bool> action)
{
list.SetOnScrollListener(new OnScrollListener(null, tuple =>
{
action.Invoke(tuple.Item2 == ScrollState.Fling);
}));
}
public void OnScrollStateChanged(AbsListView view, [GeneratedEnum] ScrollState scrollState)
{
if (scrollState == ScrollState.Idle)
{
Element?.OnScrolled(this, EventArgs.Empty);
}
}
void IOnScrollListener.OnScrollStateChanged(AbsListView view, ScrollState scrollState)
{
if (_onScrollListener != null)
{
_onScrollListener.OnScrollStateChanged(view, scrollState);
}
}
